text: // Licensed to the .NET Foundation under one or more agreements.
  // The .NET Foundation licenses this file to you under the MIT license.
  
  /*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XX                                                                           XX
  XX                           Compiler                                        XX
  XX                                                                           XX
  XX  Represents the method data we are currently JIT-compiling.               XX
  XX  An instance of this class is created for every method we JIT.            XX
  XX  This contains all the info needed for the method. So allocating a        XX
  XX  a new instance per method makes it thread-safe.                          XX
  XX  It should be used to do all the memory management for the compiler run.  XX
  XX                                                                           XX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  */
  
  /*****************************************************************************/
  #ifndef _COMPILER_H_
  #define _COMPILER_H_
  /*****************************************************************************/
  
  #include "jit.h"
  #include "opcode.h"
  #include "varset.h"
  #include "jitstd.h"
  #include "jithashtable.h"
  #include "gentree.h"
  #include "debuginfo.h"
  #include "lir.h"
  #include "block.h"
  #include "inline.h"
  #include "jiteh.h"
  #include "instr.h"
  #include "regalloc.h"
  #include "sm.h"
  #include "cycletimer.h"
  #include "blockset.h"
  #include "arraystack.h"
  #include "hashbv.h"
  #include "jitexpandarray.h"
  #include "tinyarray.h"
  #include "valuenum.h"
  #include "jittelemetry.h"
  #include "namedintrinsiclist.h"
  #ifdef LATE_DISASM
  #include "disasm.h"
  #endif
  
  #include "codegeninterface.h"
  #include "regset.h"
  #include "jitgcinfo.h"
  
  #if DUMP_GC_TABLES && defined(JIT32_GCENCODER)
  #include "gcdump.h"
  #endif
  
  #include "emit.h"
  
  #include "hwintrinsic.h"
  #include "simd.h"
  #include "simdashwintrinsic.h"
  
  // This is only used locally in the JIT to indicate that
  // a verification block should be inserted
  #define SEH_VERIFICATION_EXCEPTION 0xe0564552 // VER
  
  /*****************************************************************************
   *                  Forward declarations
   */
  
  struct InfoHdr;            // defined in GCInfo.h
  struct escapeMapping_t;    // defined in fgdiagnostic.cpp
  class emitter;             // defined in emit.h
  struct ShadowParamVarInfo; // defined in GSChecks.cpp
  struct InitVarDscInfo;     // defined in register_arg_convention.h
  class FgStack;             // defined in fgbasic.cpp
  class Instrumentor;        // defined in fgprofile.cpp
  class SpanningTreeVisitor; // defined in fgprofile.cpp
  class CSE_DataFlow;        // defined in OptCSE.cpp
  class OptBoolsDsc;         // defined in optimizer.cpp
  #ifdef DEBUG
  struct IndentStack;
  #endif
  
  class Lowering; // defined in lower.h
  
  // The following are defined in this file, Compiler.h
  
  class Compiler;
  
  /*****************************************************************************
   *                  Unwind info
   */
  
  #include "unwind.h"
  
  /*****************************************************************************/
  
  //
  // Declare global operator new overloads that use the compiler's arena allocator
  //
  
  // I wanted to make the second argument optional, with default = CMK_Unknown, but that
  // caused these to be ambiguous with the global placement new operators.
  void* __cdecl operator new(size_t n, Compiler* context, CompMemKind cmk);
  void* __cdecl operator new[](size_t n, Compiler* context, CompMemKind cmk);
  void* __cdecl operator new(size_t n, void* p, const jitstd::placement_t& syntax_difference);
  
  // Requires the definitions of "operator new" so including "LoopCloning.h" after the definitions.
  #include "loopcloning.h"
  
  /*****************************************************************************/
  
  /* This is included here and not earlier as it needs the definition of "CSE"
   * which is defined in the section above */
  
  /*****************************************************************************/
  
  unsigned genLog2(unsigned value);
  unsigned genLog2(unsigned __int64 value);
  
  unsigned ReinterpretHexAsDecimal(unsigned in);
  
  /*****************************************************************************/
  
  const unsigned FLG_CCTOR = (CORINFO_FLG_CONSTRUCTOR | CORINFO_FLG_STATIC);
  
  #ifdef DEBUG
  const int BAD_STK_OFFS = 0xBAADF00D; // for LclVarDsc::lvStkOffs
  #endif
  
  //------------------------------------------------------------------------
  // HFA info shared by LclVarDsc and fgArgTabEntry
  //------------------------------------------------------------------------
  inline bool IsHfa(CorInfoHFAElemType kind)
  {
      return kind != CORINFO_HFA_ELEM_NONE;
  }
  inline var_types HfaTypeFromElemKind(CorInfoHFAElemType kind)
  {
      switch (kind)
      {
          case CORINFO_HFA_ELEM_FLOAT:
              return TYP_FLOAT;
          case CORINFO_HFA_ELEM_DOUBLE:
              return TYP_DOUBLE;
  #ifdef FEATURE_SIMD
          case CORINFO_HFA_ELEM_VECTOR64:
              return TYP_SIMD8;
          case CORINFO_HFA_ELEM_VECTOR128:
              return TYP_SIMD16;
  #endif
          case CORINFO_HFA_ELEM_NONE:
              return TYP_UNDEF;
          default:
              assert(!"Invalid HfaElemKind");
              return TYP_UNDEF;
      }
  }
  inline CorInfoHFAElemType HfaElemKindFromType(var_types type)
  {
      switch (type)
      {
          case TYP_FLOAT:
              return CORINFO_HFA_ELEM_FLOAT;
          case TYP_DOUBLE:
              return CORINFO_HFA_ELEM_DOUBLE;
  #ifdef FEATURE_SIMD
          case TYP_SIMD8:
              return CORINFO_HFA_ELEM_VECTOR64;
          case TYP_SIMD16:
              return CORINFO_HFA_ELEM_VECTOR128;
  #endif
          case TYP_UNDEF:
              return CORINFO_HFA_ELEM_NONE;
          default:
              assert(!"Invalid HFA Type");
              return CORINFO_HFA_ELEM_NONE;
      }
  }
  
  // The following holds the Local var info (scope information)
  typedef const char* VarName; // Actual ASCII string
  struct VarScopeDsc
  {
      unsigned vsdVarNum; // (remapped) LclVarDsc number
      unsigned vsdLVnum;  // 'which' in eeGetLVinfo().
                          // Also, it is the index of this entry in the info.compVarScopes array,
                          // which is useful since the array is also accessed via the
                          // compEnterScopeList and compExitScopeList sorted arrays.
  
      IL_OFFSET vsdLifeBeg; // instr offset of beg of life
      IL_OFFSET vsdLifeEnd; // instr offset of end of life
  
  #ifdef DEBUG
      VarName vsdName; // name of the var
  #endif
  };
  
  // This class stores information associated with a LclVar SSA definition.
  class LclSsaVarDsc
  {
      // The basic block where the definition occurs. Definitions of uninitialized variables
      // are considered to occur at the start of the first basic block (fgFirstBB).
      //
      // TODO-Cleanup: In the case of uninitialized variables the block is set to nullptr by
      // SsaBuilder and changed to fgFirstBB during value numbering. It would be useful to
      // investigate and perhaps eliminate this rather unexpected behavior.
      BasicBlock* m_block;
      // The GT_ASG node that generates the definition, or nullptr for definitions
      // of uninitialized variables.
      GenTreeOp* m_asg;
  
  public:
      LclSsaVarDsc() : m_block(nullptr), m_asg(nullptr)
      {
      }
  
      LclSsaVarDsc(BasicBlock* block, GenTreeOp* asg) : m_block(block), m_asg(asg)
      {
          assert((asg == nullptr) || asg->OperIs(GT_ASG));
      }
  
      BasicBlock* GetBlock() const
      {
          return m_block;
      }
  
      void SetBlock(BasicBlock* block)
      {
          m_block = block;
      }
  
      GenTreeOp* GetAssignment() const
      {
          return m_asg;
      }
  
      void SetAssignment(GenTreeOp* asg)
      {
          assert((asg == nullptr) || asg->OperIs(GT_ASG));
          m_asg = asg;
      }
  
      ValueNumPair m_vnPair;
  };
  
  // This class stores information associated with a memory SSA definition.
  class SsaMemDef
  {
  public:
      ValueNumPair m_vnPair;
  };
  
  //------------------------------------------------------------------------
  // SsaDefArray: A resizable array of SSA definitions.
  //
  // Unlike an ordinary resizable array implementation, this allows only element
  // addition (by calling AllocSsaNum) and has special handling for RESERVED_SSA_NUM
  // (basically it's a 1-based array). The array doesn't impose any particular
  // requirements on the elements it stores and AllocSsaNum forwards its arguments
  // to the array element constructor, this way the array supports both LclSsaVarDsc
  // and SsaMemDef elements.
  //
  template <typename T>
  class SsaDefArray
  {
      T*       m_array;
      unsigned m_arraySize;
      unsigned m_count;
  
      static_assert_no_msg(SsaConfig::RESERVED_SSA_NUM == 0);
      static_assert_no_msg(SsaConfig::FIRST_SSA_NUM == 1);
  
      // Get the minimum valid SSA number.
      unsigned GetMinSsaNum() const
      {
          return SsaConfig::FIRST_SSA_NUM;
      }
  
      // Increase (double) the size of the array.
      void GrowArray(CompAllocator alloc)
      {
          unsigned oldSize = m_arraySize;
          unsigned newSize = max(2, oldSize * 2);
  
          T* newArray = alloc.allocate<T>(newSize);
  
          for (unsigned i = 0; i < oldSize; i++)
          {
              newArray[i] = m_array[i];
          }
  
          m_array     = newArray;
          m_arraySize = newSize;
      }
  
  public:
      // Construct an empty SsaDefArray.
      SsaDefArray() : m_array(nullptr), m_arraySize(0), m_count(0)
      {
      }
  
      // Reset the array (used only if the SSA form is reconstructed).
      void Reset()
      {
          m_count = 0;
      }
  
      // Allocate a new SSA number (starting with SsaConfig::FIRST_SSA_NUM).
      template <class... Args>
      unsigned AllocSsaNum(CompAllocator alloc, Args&&... args)
      {
          if (m_count == m_arraySize)
          {
              GrowArray(alloc);
          }
  
          unsigned ssaNum    = GetMinSsaNum() + m_count;
          m_array[m_count++] = T(std::forward<Args>(args)...);
  
          // Ensure that the first SSA number we allocate is SsaConfig::FIRST_SSA_NUM
          assert((ssaNum == SsaConfig::FIRST_SSA_NUM) || (m_count > 1));
  
          return ssaNum;
      }
  
      // Get the number of SSA definitions in the array.
      unsigned GetCount() const
      {
          return m_count;
      }
  
      // Get a pointer to the SSA definition at the specified index.
      T* GetSsaDefByIndex(unsigned index)
      {
          assert(index < m_count);
          return &m_array[index];
      }
  
      // Check if the specified SSA number is valid.
      bool IsValidSsaNum(unsigned ssaNum) const
      {
          return (GetMinSsaNum() <= ssaNum) && (ssaNum < (GetMinSsaNum() + m_count));
      }
  
      // Get a pointer to the SSA definition associated with the specified SSA number.
      T* GetSsaDef(unsigned ssaNum)
      {
          assert(ssaNum != SsaConfig::RESERVED_SSA_NUM);
          return GetSsaDefByIndex(ssaNum - GetMinSsaNum());
      }
  };
  
  enum RefCountState
  {
      RCS_INVALID, // not valid to get/set ref counts
      RCS_EARLY,   // early counts for struct promotion and struct passing
      RCS_NORMAL,  // normal ref counts (from lvaMarkRefs onward)
  };
  
  #ifdef DEBUG
  // Reasons why we can't enregister a local.
  enum class DoNotEnregisterReason
  {
      None,
      AddrExposed,      // the address of this local is exposed.
      DontEnregStructs, // struct enregistration is disabled.
      NotRegSizeStruct, // the struct size does not much any register size, usually the struct size is too big.
      LocalField,       // the local is accessed with LCL_FLD, note we can do it not only for struct locals.
      VMNeedsStackAddr,
      LiveInOutOfHandler, // the local is alive in and out of exception handler and not signle def.
      BlockOp,            // Is read or written via a block operation.
      IsStructArg,        // Is a struct passed as an argument in a way that requires a stack location.
      DepField,           // It is a field of a dependently promoted struct
      NoRegVars,          // opts.compFlags & CLFLG_REGVAR is not set
      MinOptsGC,          // It is a GC Ref and we are compiling MinOpts
  #if !defined(TARGET_64BIT)
      LongParamField, // It is a decomposed field of a long parameter.
  #endif
  #ifdef JIT32_GCENCODER
      PinningRef,
  #endif
      LclAddrNode, // the local is accessed with LCL_ADDR_VAR/FLD.
      CastTakesAddr,
      StoreBlkSrc,      // the local is used as STORE_BLK source.
      OneAsgRetyping,   // fgMorphOneAsgBlockOp prevents this local from being enregister.
      SwizzleArg,       // the local is passed using LCL_FLD as another type.
      BlockOpRet,       // the struct is returned and it promoted or there is a cast.
      ReturnSpCheck,    // the local is used to do SP check
      SimdUserForcesDep // a promoted struct was used by a SIMD/HWI node; it must be dependently promoted
  };
  
  enum class AddressExposedReason
  {
      NONE,
      PARENT_EXPOSED,   // This is a promoted field but the parent is exposed.
      TOO_CONSERVATIVE, // Were marked as exposed to be conservative, fix these places.
      ESCAPE_ADDRESS,   // The address is escaping, for example, passed as call argument.
      WIDE_INDIR,       // We access via indirection with wider type.
      OSR_EXPOSED,      // It was exposed in the original method, osr has to repeat it.
      STRESS_LCL_FLD,   // Stress mode replaces localVar with localFld and makes them addrExposed.
      COPY_FLD_BY_FLD,  // Field by field copy takes the address of the local, can be fixed.
      DISPATCH_RET_BUF  // Caller return buffer dispatch.
  };
  
  #endif // DEBUG
  
  class LclVarDsc
  {
  public:
      // The constructor. Most things can just be zero'ed.
      //
      // Initialize the ArgRegs to REG_STK.
      // Morph will update if this local is passed in a register.
      LclVarDsc()
          : _lvArgReg(REG_STK)
          ,
  #if FEATURE_MULTIREG_ARGS
          _lvOtherArgReg(REG_STK)
          ,
  #endif // FEATURE_MULTIREG_ARGS
          lvClassHnd(NO_CLASS_HANDLE)
          , lvRefBlks(BlockSetOps::UninitVal())
          , lvPerSsaData()
      {
      }
  
      // note this only packs because var_types is a typedef of unsigned char
      var_types lvType : 5; // TYP_INT/LONG/FLOAT/DOUBLE/REF
  
      unsigned char lvIsParam : 1;           // is this a parameter?
      unsigned char lvIsRegArg : 1;          // is this an argument that was passed by register?
      unsigned char lvFramePointerBased : 1; // 0 = off of REG_SPBASE (e.g., ESP), 1 = off of REG_FPBASE (e.g., EBP)
  
      unsigned char lvOnFrame : 1;  // (part of) the variable lives on the frame
      unsigned char lvRegister : 1; // assigned to live in a register? For RyuJIT backend, this is only set if the
                                    // variable is in the same register for the entire function.
      unsigned char lvTracked : 1;  // is this a tracked variable?
      bool          lvTrackedNonStruct()
      {
          return lvTracked && lvType != TYP_STRUCT;
      }
      unsigned char lvPinned : 1; // is this a pinned variable?
  
      unsigned char lvMustInit : 1; // must be initialized
  
  private:
      bool m_addrExposed : 1; // The address of this variable is "exposed" -- passed as an argument, stored in a
                              // global location, etc.
                              // We cannot reason reliably about the value of the variable.
  public:
      unsigned char lvDoNotEnregister : 1; // Do not enregister this variable.
      unsigned char lvFieldAccessed : 1;   // The var is a struct local, and a field of the variable is accessed.  Affects
                                           // struct promotion.
      unsigned char lvLiveInOutOfHndlr : 1; // The variable is live in or out of an exception handler, and therefore must
                                            // be on the stack (at least at those boundaries.)
  
      unsigned char lvInSsa : 1;       // The variable is in SSA form (set by SsaBuilder)
      unsigned char lvIsCSE : 1;       // Indicates if this LclVar is a CSE variable.
      unsigned char lvHasLdAddrOp : 1; // has ldloca or ldarga opcode on this local.
      unsigned char lvStackByref : 1;  // This is a compiler temporary of TYP_BYREF that is known to point into our local
                                       // stack frame.
  
      unsigned char lvHasILStoreOp : 1;         // there is at least one STLOC or STARG on this local
      unsigned char lvHasMultipleILStoreOp : 1; // there is more than one STLOC on this local
  
      unsigned char lvIsTemp : 1; // Short-lifetime compiler temp
  
  #if defined(TARGET_AMD64) || defined(TARGET_ARM64)
      unsigned char lvIsImplicitByRef : 1; // Set if the argument is an implicit byref.
  #endif                                   // defined(TARGET_AMD64) || defined(TARGET_ARM64)
  
      unsigned char lvIsBoolean : 1; // set if variable is boolean
      unsigned char lvSingleDef : 1; // variable has a single def
                                     // before lvaMarkLocalVars: identifies ref type locals that can get type updates
                                     // after lvaMarkLocalVars: identifies locals that are suitable for optAddCopies
  
      unsigned char lvSingleDefRegCandidate : 1; // variable has a single def and hence is a register candidate
                                                 // Currently, this is only used to decide if an EH variable can be
                                                 // a register candiate or not.
  
      unsigned char lvDisqualifySingleDefRegCandidate : 1; // tracks variable that are disqualified from register
                                                           // candidancy
  
      unsigned char lvSpillAtSingleDef : 1; // variable has a single def (as determined by LSRA interval scan)
                                            // and is spilled making it candidate to spill right after the
                                            // first (and only) definition.
                                            // Note: We cannot reuse lvSingleDefRegCandidate because it is set
                                            // in earlier phase and the information might not be appropriate
                                            // in LSRA.
  
      unsigned char lvDisqualify : 1;   // variable is no longer OK for add copy optimization
      unsigned char lvVolatileHint : 1; // hint for AssertionProp
  
  #ifndef TARGET_64BIT
      unsigned char lvStructDoubleAlign : 1; // Must we double align this struct?
  #endif                                     // !TARGET_64BIT
  #ifdef TARGET_64BIT
      unsigned char lvQuirkToLong : 1; // Quirk to allocate this LclVar as a 64-bit long
  #endif
  #ifdef DEBUG
      unsigned char lvKeepType : 1;       // Don't change the type of this variable
      unsigned char lvNoLclFldStress : 1; // Can't apply local field stress on this one
  #endif
      unsigned char lvIsPtr : 1; // Might this be used in an address computation? (used by buffer overflow security
                                 // checks)
      unsigned char lvIsUnsafeBuffer : 1; // Does this contain an unsafe buffer requiring buffer overflow security checks?
      unsigned char lvPromoted : 1; // True when this local is a promoted struct, a normed struct, or a "split" long on a
                                    // 32-bit target.  For implicit byref parameters, this gets hijacked between
                                    // fgRetypeImplicitByRefArgs and fgMarkDemotedImplicitByRefArgs to indicate whether
                                    // references to the arg are being rewritten as references to a promoted shadow local.
      unsigned char lvIsStructField : 1;     // Is this local var a field of a promoted struct local?
      unsigned char lvOverlappingFields : 1; // True when we have a struct with possibly overlapping fields
      unsigned char lvContainsHoles : 1;     // True when we have a promoted struct that contains holes
      unsigned char lvCustomLayout : 1;      // True when this struct has "CustomLayout"
  
      unsigned char lvIsMultiRegArg : 1; // true if this is a multireg LclVar struct used in an argument context
      unsigned char lvIsMultiRegRet : 1; // true if this is a multireg LclVar struct assigned from a multireg call
  
  #ifdef FEATURE_HFA_FIELDS_PRESENT
      CorInfoHFAElemType _lvHfaElemKind : 3; // What kind of an HFA this is (CORINFO_HFA_ELEM_NONE if it is not an HFA).
  #endif                                     // FEATURE_HFA_FIELDS_PRESENT
  
  #ifdef DEBUG
      // TODO-Cleanup: See the note on lvSize() - this flag is only in use by asserts that are checking for struct
      // types, and is needed because of cases where TYP_STRUCT is bashed to an integral type.
      // Consider cleaning this up so this workaround is not required.
      unsigned char lvUnusedStruct : 1; // All references to this promoted struct are through its field locals.
                                        // I.e. there is no longer any reference to the struct directly.
                                        // In this case we can simply remove this struct local.
  
      unsigned char lvUndoneStructPromotion : 1; // The struct promotion was undone and hence there should be no
                                                 // reference to the fields of this struct.
  #endif
  
      unsigned char lvLRACandidate : 1; // Tracked for linear scan register allocation purposes
  
  #ifdef FEATURE_SIMD
      // Note that both SIMD vector args and locals are marked as lvSIMDType = true, but the
      // type of an arg node is TYP_BYREF and a local node is TYP_SIMD*.
      unsigned char lvSIMDType : 1;            // This is a SIMD struct
      unsigned char lvUsedInSIMDIntrinsic : 1; // This tells lclvar is used for simd intrinsic
      unsigned char lvSimdBaseJitType : 5;     // Note: this only packs because CorInfoType has less than 32 entries
  
      CorInfoType GetSimdBaseJitType() const
      {
          return (CorInfoType)lvSimdBaseJitType;
      }
  
      void SetSimdBaseJitType(CorInfoType simdBaseJitType)
      {
          assert(simdBaseJitType < (1 << 5));
          lvSimdBaseJitType = (unsigned char)simdBaseJitType;
      }
  
      var_types GetSimdBaseType() const;
  #endif                             // FEATURE_SIMD
      unsigned char lvRegStruct : 1; // This is a reg-sized non-field-addressed struct.
  
      unsigned char lvClassIsExact : 1; // lvClassHandle is the exact type
  
  #ifdef DEBUG
      unsigned char lvClassInfoUpdated : 1; // true if this var has updated class handle or exactness
  #endif
  
      unsigned char lvImplicitlyReferenced : 1; // true if there are non-IR references to this local (prolog, epilog, gc,
                                                // eh)
  
      unsigned char lvSuppressedZeroInit : 1; // local needs zero init if we transform tail call to loop
  
      unsigned char lvHasExplicitInit : 1; // The local is explicitly initialized and doesn't need zero initialization in
                                           // the prolog. If the local has gc pointers, there are no gc-safe points
                                           // between the prolog and the explicit initialization.
  
      union {
          unsigned lvFieldLclStart; // The index of the local var representing the first field in the promoted struct
                                    // local.  For implicit byref parameters, this gets hijacked between
                                    // fgRetypeImplicitByRefArgs and fgMarkDemotedImplicitByRefArgs to point to the
                                    // struct local created to model the parameter's struct promotion, if any.
          unsigned lvParentLcl; // The index of the local var representing the parent (i.e. the promoted struct local).
                                // Valid on promoted struct local fields.
      };
  
      unsigned char lvFieldCnt; //  Number of fields in the promoted VarDsc.
      unsigned char lvFldOffset;
      unsigned char lvFldOrdinal;
  
  #ifdef DEBUG
      unsigned char lvSingleDefDisqualifyReason = 'H';
  #endif
  
  #if FEATURE_MULTIREG_ARGS
      regNumber lvRegNumForSlot(unsigned slotNum)
      {
          if (slotNum == 0)
          {
              return (regNumber)_lvArgReg;
          }
          else if (slotNum == 1)
          {
              return GetOtherArgReg();
          }
          else
          {
              assert(false && "Invalid slotNum!");
          }
  
          unreached();
      }
  #endif // FEATURE_MULTIREG_ARGS
  
      CorInfoHFAElemType GetLvHfaElemKind() const
      {
  #ifdef FEATURE_HFA_FIELDS_PRESENT
          return _lvHfaElemKind;
  #else
          NOWAY_MSG("GetLvHfaElemKind");
          return CORINFO_HFA_ELEM_NONE;
  #endif // FEATURE_HFA_FIELDS_PRESENT
      }
  
      void SetLvHfaElemKind(CorInfoHFAElemType elemKind)
      {
  #ifdef FEATURE_HFA_FIELDS_PRESENT
          _lvHfaElemKind = elemKind;
  #else
          NOWAY_MSG("SetLvHfaElemKind");
  #endif // FEATURE_HFA_FIELDS_PRESENT
      }
  
      bool lvIsHfa() const
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              return IsHfa(GetLvHfaElemKind());
          }
          else
          {
              return false;
          }
      }
  
      bool lvIsHfaRegArg() const
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              return lvIsRegArg && lvIsHfa();
          }
          else
          {
              return false;
          }
      }
  
      //------------------------------------------------------------------------------
      // lvHfaSlots: Get the number of slots used by an HFA local
      //
      // Return Value:
      //    On Arm64 - Returns 1-4 indicating the number of register slots used by the HFA
      //    On Arm32 - Returns the total number of single FP register slots used by the HFA, max is 8
      //
      unsigned lvHfaSlots() const
      {
          assert(lvIsHfa());
          assert(varTypeIsStruct(lvType));
          unsigned slots = 0;
  #ifdef TARGET_ARM
          slots = lvExactSize / sizeof(float);
          assert(slots <= 8);
  #elif defined(TARGET_ARM64)
          switch (GetLvHfaElemKind())
          {
              case CORINFO_HFA_ELEM_NONE:
                  assert(!"lvHfaSlots called for non-HFA");
                  break;
              case CORINFO_HFA_ELEM_FLOAT:
                  assert((lvExactSize % 4) == 0);
                  slots = lvExactSize >> 2;
                  break;
              case CORINFO_HFA_ELEM_DOUBLE:
              case CORINFO_HFA_ELEM_VECTOR64:
                  assert((lvExactSize % 8) == 0);
                  slots = lvExactSize >> 3;
                  break;
              case CORINFO_HFA_ELEM_VECTOR128:
                  assert((lvExactSize % 16) == 0);
                  slots = lvExactSize >> 4;
                  break;
              default:
                  unreached();
          }
          assert(slots <= 4);
  #endif //  TARGET_ARM64
          return slots;
      }
  
      // lvIsMultiRegArgOrRet()
      //     returns true if this is a multireg LclVar struct used in an argument context
      //               or if this is a multireg LclVar struct assigned from a multireg call
      bool lvIsMultiRegArgOrRet()
      {
          return lvIsMultiRegArg || lvIsMultiRegRet;
      }
  
  #if defined(DEBUG)
  private:
      DoNotEnregisterReason m_doNotEnregReason;
  
      AddressExposedReason m_addrExposedReason;
  
  public:
      void SetDoNotEnregReason(DoNotEnregisterReason reason)
      {
          m_doNotEnregReason = reason;
      }
  
      DoNotEnregisterReason GetDoNotEnregReason() const
      {
          return m_doNotEnregReason;
      }
  
      AddressExposedReason GetAddrExposedReason() const
      {
          return m_addrExposedReason;
      }
  #endif // DEBUG
  
  public:
      void SetAddressExposed(bool value DEBUGARG(AddressExposedReason reason))
      {
          m_addrExposed = value;
          INDEBUG(m_addrExposedReason = reason);
      }
  
      void CleanAddressExposed()
      {
          m_addrExposed = false;
      }
  
      bool IsAddressExposed() const
      {
          return m_addrExposed;
      }
  
  private:
      regNumberSmall _lvRegNum; // Used to store the register this variable is in (or, the low register of a
                                // register pair). It is set during codegen any time the
                                // variable is enregistered (lvRegister is only set
                                // to non-zero if the variable gets the same register assignment for its entire
                                // lifetime).
  #if !defined(TARGET_64BIT)
      regNumberSmall _lvOtherReg; // Used for "upper half" of long var.
  #endif                          // !defined(TARGET_64BIT)
  
      regNumberSmall _lvArgReg; // The (first) register in which this argument is passed.
  
  #if FEATURE_MULTIREG_ARGS
      regNumberSmall _lvOtherArgReg; // Used for the second part of the struct passed in a register.
                                     // Note this is defined but not used by ARM32
  #endif                             // FEATURE_MULTIREG_ARGS
  
      regNumberSmall _lvArgInitReg; // the register into which the argument is moved at entry
  
  public:
      // The register number is stored in a small format (8 bits), but the getters return and the setters take
      // a full-size (unsigned) format, to localize the casts here.
  
      /////////////////////
  
      regNumber GetRegNum() const
      {
          return (regNumber)_lvRegNum;
      }
  
      void SetRegNum(regNumber reg)
      {
          _lvRegNum = (regNumberSmall)reg;
          assert(_lvRegNum == reg);
      }
  
  /////////////////////
  
  #if defined(TARGET_64BIT)
  
      regNumber GetOtherReg() const
      {
          assert(!"shouldn't get here"); // can't use "unreached();" because it's NORETURN, which causes C4072
                                         // "unreachable code" warnings
          return REG_NA;
      }
  
      void SetOtherReg(regNumber reg)
      {
          assert(!"shouldn't get here"); // can't use "unreached();" because it's NORETURN, which causes C4072
                                         // "unreachable code" warnings
      }
  #else  // !TARGET_64BIT
  
      regNumber GetOtherReg() const
      {
          return (regNumber)_lvOtherReg;
      }
  
      void SetOtherReg(regNumber reg)
      {
          _lvOtherReg = (regNumberSmall)reg;
          assert(_lvOtherReg == reg);
      }
  #endif // !TARGET_64BIT
  
      /////////////////////
  
      regNumber GetArgReg() const
      {
          return (regNumber)_lvArgReg;
      }
  
      void SetArgReg(regNumber reg)
      {
          _lvArgReg = (regNumberSmall)reg;
          assert(_lvArgReg == reg);
      }
  
  #if FEATURE_MULTIREG_ARGS
  
      regNumber GetOtherArgReg() const
      {
          return (regNumber)_lvOtherArgReg;
      }
  
      void SetOtherArgReg(regNumber reg)
      {
          _lvOtherArgReg = (regNumberSmall)reg;
          assert(_lvOtherArgReg == reg);
      }
  #endif // FEATURE_MULTIREG_ARGS
  
  #ifdef FEATURE_SIMD
      // Is this is a SIMD struct?
      bool lvIsSIMDType() const
      {
          return lvSIMDType;
      }
  
      // Is this is a SIMD struct which is used for SIMD intrinsic?
      bool lvIsUsedInSIMDIntrinsic() const
      {
          return lvUsedInSIMDIntrinsic;
      }
  #else
      // If feature_simd not enabled, return false
      bool lvIsSIMDType() const
      {
          return false;
      }
      bool lvIsUsedInSIMDIntrinsic() const
      {
          return false;
      }
  #endif
  
      /////////////////////
  
      regNumber GetArgInitReg() const
      {
          return (regNumber)_lvArgInitReg;
      }
  
      void SetArgInitReg(regNumber reg)
      {
          _lvArgInitReg = (regNumberSmall)reg;
          assert(_lvArgInitReg == reg);
      }
  
      /////////////////////
  
      bool lvIsRegCandidate() const
      {
          return lvLRACandidate != 0;
      }
  
      bool lvIsInReg() const
      {
          return lvIsRegCandidate() && (GetRegNum() != REG_STK);
      }
  
      regMaskTP lvRegMask() const
      {
          regMaskTP regMask = RBM_NONE;
          if (varTypeUsesFloatReg(TypeGet()))
          {
              if (GetRegNum() != REG_STK)
              {
                  regMask = genRegMaskFloat(GetRegNum(), TypeGet());
              }
          }
          else
          {
              if (GetRegNum() != REG_STK)
              {
                  regMask = genRegMask(GetRegNum());
              }
          }
          return regMask;
      }
  
      unsigned short lvVarIndex; // variable tracking index
  
  private:
      unsigned short m_lvRefCnt; // unweighted (real) reference count.  For implicit by reference
                                 // parameters, this gets hijacked from fgResetImplicitByRefRefCount
                                 // through fgMarkDemotedImplicitByRefArgs, to provide a static
                                 // appearance count (computed during address-exposed analysis)
                                 // that fgMakeOutgoingStructArgCopy consults during global morph
                                 // to determine if eliding its copy is legal.
  
      weight_t m_lvRefCntWtd; // weighted reference count
  
  public:
      unsigned short lvRefCnt(RefCountState state = RCS_NORMAL) const;
      void incLvRefCnt(unsigned short delta, RefCountState state = RCS_NORMAL);
      void setLvRefCnt(unsigned short newValue, RefCountState state = RCS_NORMAL);
  
      weight_t lvRefCntWtd(RefCountState state = RCS_NORMAL) const;
      void incLvRefCntWtd(weight_t delta, RefCountState state = RCS_NORMAL);
      void setLvRefCntWtd(weight_t newValue, RefCountState state = RCS_NORMAL);
  
  private:
      int lvStkOffs; // stack offset of home in bytes.
  
  public:
      int GetStackOffset() const
      {
          return lvStkOffs;
      }
  
      void SetStackOffset(int offset)
      {
          lvStkOffs = offset;
      }
  
      unsigned lvExactSize; // (exact) size of the type in bytes
  
      // Is this a promoted struct?
      // This method returns true only for structs (including SIMD structs), not for
      // locals that are split on a 32-bit target.
      // It is only necessary to use this:
      //   1) if only structs are wanted, and
      //   2) if Lowering has already been done.
      // Otherwise lvPromoted is valid.
      bool lvPromotedStruct()
      {
  #if !defined(TARGET_64BIT)
          return (lvPromoted && !varTypeIsLong(lvType));
  #else  // defined(TARGET_64BIT)
          return lvPromoted;
  #endif // defined(TARGET_64BIT)
      }
  
      unsigned lvSize() const;
  
      size_t lvArgStackSize() const;
  
      unsigned lvSlotNum; // original slot # (if remapped)
  
      typeInfo lvVerTypeInfo; // type info needed for verification
  
      // class handle for the local or null if not known or not a class,
      // for a struct handle use `GetStructHnd()`.
      CORINFO_CLASS_HANDLE lvClassHnd;
  
      // Get class handle for a struct local or implicitByRef struct local.
      CORINFO_CLASS_HANDLE GetStructHnd() const
      {
  #ifdef FEATURE_SIMD
          if (lvSIMDType && (m_layout == nullptr))
          {
              return NO_CLASS_HANDLE;
          }
  #endif
          assert(m_layout != nullptr);
  #if defined(TARGET_AMD64) || defined(TARGET_ARM64)
          assert(varTypeIsStruct(TypeGet()) || (lvIsImplicitByRef && (TypeGet() == TYP_BYREF)));
  #else
          assert(varTypeIsStruct(TypeGet()));
  #endif
          CORINFO_CLASS_HANDLE structHnd = m_layout->GetClassHandle();
          assert(structHnd != NO_CLASS_HANDLE);
          return structHnd;
      }
  
      CORINFO_FIELD_HANDLE lvFieldHnd; // field handle for promoted struct fields
  
  private:
      ClassLayout* m_layout; // layout info for structs
  
  public:
      BlockSet   lvRefBlks;          // Set of blocks that contain refs
      Statement* lvDefStmt;          // Pointer to the statement with the single definition
      void       lvaDisqualifyVar(); // Call to disqualify a local variable from use in optAddCopies
  
      var_types TypeGet() const
      {
          return (var_types)lvType;
      }
      bool lvStackAligned() const
      {
          assert(lvIsStructField);
          return ((lvFldOffset % TARGET_POINTER_SIZE) == 0);
      }
      bool lvNormalizeOnLoad() const
      {
          return varTypeIsSmall(TypeGet()) &&
                 // lvIsStructField is treated the same as the aliased local, see fgDoNormalizeOnStore.
                 (lvIsParam || m_addrExposed || lvIsStructField);
      }
  
      bool lvNormalizeOnStore() const
      {
          return varTypeIsSmall(TypeGet()) &&
                 // lvIsStructField is treated the same as the aliased local, see fgDoNormalizeOnStore.
                 !(lvIsParam || m_addrExposed || lvIsStructField);
      }
  
      void incRefCnts(weight_t weight, Compiler* pComp, RefCountState state = RCS_NORMAL, bool propagate = true);
  
      var_types GetHfaType() const
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              assert(lvIsHfa());
              return HfaTypeFromElemKind(GetLvHfaElemKind());
          }
          else
          {
              return TYP_UNDEF;
          }
      }
  
      void SetHfaType(var_types type)
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              CorInfoHFAElemType elemKind = HfaElemKindFromType(type);
              SetLvHfaElemKind(elemKind);
              // Ensure we've allocated enough bits.
              assert(GetLvHfaElemKind() == elemKind);
          }
      }
  
      // Returns true if this variable contains GC pointers (including being a GC pointer itself).
      bool HasGCPtr() const
      {
          return varTypeIsGC(lvType) || ((lvType == TYP_STRUCT) && m_layout->HasGCPtr());
      }
  
      // Returns the layout of a struct variable.
      ClassLayout* GetLayout() const
      {
          assert(varTypeIsStruct(lvType));
          return m_layout;
      }
  
      // Sets the layout of a struct variable.
      void SetLayout(ClassLayout* layout)
      {
          assert(varTypeIsStruct(lvType));
          assert((m_layout == nullptr) || ClassLayout::AreCompatible(m_layout, layout));
          m_layout = layout;
      }
  
      SsaDefArray<LclSsaVarDsc> lvPerSsaData;
  
      // Returns the address of the per-Ssa data for the given ssaNum (which is required
      // not to be the SsaConfig::RESERVED_SSA_NUM, which indicates that the variable is
      // not an SSA variable).
      LclSsaVarDsc* GetPerSsaData(unsigned ssaNum)
      {
          return lvPerSsaData.GetSsaDef(ssaNum);
      }
  
      var_types GetRegisterType(const GenTreeLclVarCommon* tree) const;
  
      var_types GetRegisterType() const;
  
      var_types GetActualRegisterType() const;
  
      bool IsEnregisterableType() const
      {
          return GetRegisterType() != TYP_UNDEF;
      }
  
      bool IsEnregisterableLcl() const
      {
          if (lvDoNotEnregister)
          {
              return false;
          }
          return IsEnregisterableType();
      }
  
      //-----------------------------------------------------------------------------
      //  IsAlwaysAliveInMemory: Determines if this variable's value is always
      //     up-to-date on stack. This is possible if this is an EH-var or
      //     we decided to spill after single-def.
      //
      bool IsAlwaysAliveInMemory() const
      {
          return lvLiveInOutOfHndlr || lvSpillAtSingleDef;
      }
  
      bool CanBeReplacedWithItsField(Compiler* comp) const;
  
  #ifdef DEBUG
  public:
      const char* lvReason;
  
      void PrintVarReg() const
      {
          printf("%s", getRegName(GetRegNum()));
      }
  #endif // DEBUG
  
  }; // class LclVarDsc
  
  enum class SymbolicIntegerValue : int32_t
  {
      LongMin,
      IntMin,
      ShortMin,
      ByteMin,
      Zero,
      One,
      ByteMax,
      UByteMax,
      ShortMax,
      UShortMax,
      IntMax,
      UIntMax,
      LongMax,
  };
  
  inline constexpr bool operator>(SymbolicIntegerValue left, SymbolicIntegerValue right)
  {
      return static_cast<int32_t>(left) > static_cast<int32_t>(right);
  }
  
  inline constexpr bool operator>=(SymbolicIntegerValue left, SymbolicIntegerValue right)
  {
      return static_cast<int32_t>(left) >= static_cast<int32_t>(right);
  }
  
  inline constexpr bool operator<(SymbolicIntegerValue left, SymbolicIntegerValue right)
  {
      return static_cast<int32_t>(left) < static_cast<int32_t>(right);
  }
  
  inline constexpr bool operator<=(SymbolicIntegerValue left, SymbolicIntegerValue right)
  {
      return static_cast<int32_t>(left) <= static_cast<int32_t>(right);
  }
  
  // Represents an integral range useful for reasoning about integral casts.
  // It uses a symbolic representation for lower and upper bounds so
  // that it can efficiently handle integers of all sizes on all hosts.
  //
  // Note that the ranges represented by this class are **always** in the
  // "signed" domain. This is so that if we know the range a node produces, it
  // can be trivially used to determine if a cast above the node does or does not
  // overflow, which requires that the interpretation of integers be the same both
  // for the "input" and "output". We choose signed interpretation here because it
  // produces nice continuous ranges and because IR uses sign-extension for constants.
  //
  // Some examples of how ranges are computed for casts:
  // 1. CAST_OVF(ubyte <- uint): does not overflow for [0..UBYTE_MAX], produces the
  //    same range - all casts that do not change the representation, i. e. have the same
  //    "actual" input and output type, have the same "input" and "output" range.
  // 2. CAST_OVF(ulong <- uint): never oveflows => the "input" range is [INT_MIN..INT_MAX]
  //    (aka all possible 32 bit integers). Produces [0..UINT_MAX] (aka all possible 32
  //    bit integers zero-extended to 64 bits).
  // 3. CAST_OVF(int <- uint): overflows for inputs larger than INT_MAX <=> less than 0
  //    when interpreting as signed => the "input" range is [0..INT_MAX], the same range
  //    being the produced one as the node does not change the width of the integer.
  //
  class IntegralRange
  {
  private:
      SymbolicIntegerValue m_lowerBound;
      SymbolicIntegerValue m_upperBound;
  
  public:
      IntegralRange() = default;
  
      IntegralRange(SymbolicIntegerValue lowerBound, SymbolicIntegerValue upperBound)
          : m_lowerBound(lowerBound), m_upperBound(upperBound)
      {
          assert(lowerBound <= upperBound);
      }
  
      bool Contains(int64_t value) const;
  
      bool Contains(IntegralRange other) const
      {
          return (m_lowerBound <= other.m_lowerBound) && (other.m_upperBound <= m_upperBound);
      }
  
      bool IsPositive()
      {
          return m_lowerBound >= SymbolicIntegerValue::Zero;
      }
  
      bool Equals(IntegralRange other) const
      {
          return (m_lowerBound == other.m_lowerBound) && (m_upperBound == other.m_upperBound);
      }
  
      static int64_t SymbolicToRealValue(SymbolicIntegerValue value);
      static SymbolicIntegerValue LowerBoundForType(var_types type);
      static SymbolicIntegerValue UpperBoundForType(var_types type);
  
      static IntegralRange ForType(var_types type)
      {
          return {LowerBoundForType(type), UpperBoundForType(type)};
      }
  
      static IntegralRange ForNode(GenTree* node, Compiler* compiler);
      static IntegralRange ForCastInput(GenTreeCast* cast);
      static IntegralRange ForCastOutput(GenTreeCast* cast);
  
  #ifdef DEBUG
      static void Print(IntegralRange range);
  #endif // DEBUG
  };
  
  /*
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XX                                                                           XX
  XX                           TempsInfo                                       XX
  XX                                                                           XX
  XX  The temporary lclVars allocated by the compiler for code generation      XX
  XX                                                                           XX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  */
  
  /*****************************************************************************
   *
   *  The following keeps track of temporaries allocated in the stack frame
   *  during code-generation (after register allocation). These spill-temps are
   *  only used if we run out of registers while evaluating a tree.
   *
   *  These are different from the more common temps allocated by lvaGrabTemp().
   */
  
  class TempDsc
  {
  public:
      TempDsc* tdNext;
  
  private:
      int tdOffs;
  #ifdef DEBUG
      static const int BAD_TEMP_OFFSET = 0xDDDDDDDD; // used as a sentinel "bad value" for tdOffs in DEBUG
  #endif                                             // DEBUG
  
      int       tdNum;
      BYTE      tdSize;
      var_types tdType;
  
  public:
      TempDsc(int _tdNum, unsigned _tdSize, var_types _tdType) : tdNum(_tdNum), tdSize((BYTE)_tdSize), tdType(_tdType)
      {
  #ifdef DEBUG
          // temps must have a negative number (so they have a different number from all local variables)
          assert(tdNum < 0);
          tdOffs = BAD_TEMP_OFFSET;
  #endif // DEBUG
          if (tdNum != _tdNum)
          {
              IMPL_LIMITATION("too many spill temps");
          }
      }
  
  #ifdef DEBUG
      bool tdLegalOffset() const
      {
          return tdOffs != BAD_TEMP_OFFSET;
      }
  #endif // DEBUG
  
      int tdTempOffs() const
      {
          assert(tdLegalOffset());
          return tdOffs;
      }
      void tdSetTempOffs(int offs)
      {
          tdOffs = offs;
          assert(tdLegalOffset());
      }
      void tdAdjustTempOffs(int offs)
      {
          tdOffs += offs;
          assert(tdLegalOffset());
      }
  
      int tdTempNum() const
      {
          assert(tdNum < 0);
          return tdNum;
      }
      unsigned tdTempSize() const
      {
          return tdSize;
      }
      var_types tdTempType() const
      {
          return tdType;
      }
  };
  
  // interface to hide linearscan implementation from rest of compiler
  class LinearScanInterface
  {
  public:
      virtual void doLinearScan()                                = 0;
      virtual void recordVarLocationsAtStartOfBB(BasicBlock* bb) = 0;
      virtual bool willEnregisterLocalVars() const               = 0;
  #if TRACK_LSRA_STATS
      virtual void dumpLsraStatsCsv(FILE* file)     = 0;
      virtual void dumpLsraStatsSummary(FILE* file) = 0;
  #endif // TRACK_LSRA_STATS
  };
  
  LinearScanInterface* getLinearScanAllocator(Compiler* comp);
  
  // Information about arrays: their element type and size, and the offset of the first element.
  // We label GT_IND's that are array indices with GTF_IND_ARR_INDEX, and, for such nodes,
  // associate an array info via the map retrieved by GetArrayInfoMap().  This information is used,
  // for example, in value numbering of array index expressions.
  struct ArrayInfo
  {
      var_types            m_elemType;
      CORINFO_CLASS_HANDLE m_elemStructType;
      unsigned             m_elemSize;
      unsigned             m_elemOffset;
  
      ArrayInfo() : m_elemType(TYP_UNDEF), m_elemStructType(nullptr), m_elemSize(0), m_elemOffset(0)
      {
      }
  
      ArrayInfo(var_types elemType, unsigned elemSize, unsigned elemOffset, CORINFO_CLASS_HANDLE elemStructType)
          : m_elemType(elemType), m_elemStructType(elemStructType), m_elemSize(elemSize), m_elemOffset(elemOffset)
      {
      }
  };
  
  // This enumeration names the phases into which we divide compilation.  The phases should completely
  // partition a compilation.
  enum Phases
  {
  #define CompPhaseNameMacro(enum_nm, string_nm, short_nm, hasChildren, parent, measureIR) enum_nm,
  #include "compphases.h"
      PHASE_NUMBER_OF
  };
  
  extern const char*   PhaseNames[];
  extern const char*   PhaseEnums[];
  extern const LPCWSTR PhaseShortNames[];
  
  // Specify which checks should be run after each phase
  //
  enum class PhaseChecks
  {
      CHECK_NONE,
      CHECK_ALL
  };
  
  // Specify compiler data that a phase might modify
  enum class PhaseStatus : unsigned
  {
      MODIFIED_NOTHING,
      MODIFIED_EVERYTHING
  };
  
  // The following enum provides a simple 1:1 mapping to CLR API's
  enum API_ICorJitInfo_Names
  {
  #define DEF_CLR_API(name) API_##name,
  #include "ICorJitInfo_API_names.h"
      API_COUNT
  };
  
  //---------------------------------------------------------------
  // Compilation time.
  //
  
  // A "CompTimeInfo" is a structure for tracking the compilation time of one or more methods.
  // We divide a compilation into a sequence of contiguous phases, and track the total (per-thread) cycles
  // of the compilation, as well as the cycles for each phase.  We also track the number of bytecodes.
  // If there is a failure in reading a timer at any point, the "CompTimeInfo" becomes invalid, as indicated
  // by "m_timerFailure" being true.
  // If FEATURE_JIT_METHOD_PERF is not set, we define a minimal form of this, enough to let other code compile.
  struct CompTimeInfo
  {
  #ifdef FEATURE_JIT_METHOD_PERF
      // The string names of the phases.
      static const char* PhaseNames[];
  
      static bool PhaseHasChildren[];
      static int  PhaseParent[];
      static bool PhaseReportsIRSize[];
  
      unsigned         m_byteCodeBytes;
      unsigned __int64 m_totalCycles;
      unsigned __int64 m_invokesByPhase[PHASE_NUMBER_OF];
      unsigned __int64 m_cyclesByPhase[PHASE_NUMBER_OF];
  #if MEASURE_CLRAPI_CALLS
      unsigned __int64 m_CLRinvokesByPhase[PHASE_NUMBER_OF];
      unsigned __int64 m_CLRcyclesByPhase[PHASE_NUMBER_OF];
  #endif
  
      unsigned m_nodeCountAfterPhase[PHASE_NUMBER_OF];
  
      // For better documentation, we call EndPhase on
      // non-leaf phases.  We should also call EndPhase on the
      // last leaf subphase; obviously, the elapsed cycles between the EndPhase
      // for the last leaf subphase and the EndPhase for an ancestor should be very small.
      // We add all such "redundant end phase" intervals to this variable below; we print
      // it out in a report, so we can verify that it is, indeed, very small.  If it ever
      // isn't, this means that we're doing something significant between the end of the last
      // declared subphase and the end of its parent.
      unsigned __int64 m_parentPhaseEndSlop;
      bool             m_timerFailure;
  
  #if MEASURE_CLRAPI_CALLS
      // The following measures the time spent inside each individual CLR API call.
      unsigned         m_allClrAPIcalls;
      unsigned         m_perClrAPIcalls[API_ICorJitInfo_Names::API_COUNT];
      unsigned __int64 m_allClrAPIcycles;
      unsigned __int64 m_perClrAPIcycles[API_ICorJitInfo_Names::API_COUNT];
      unsigned __int32 m_maxClrAPIcycles[API_ICorJitInfo_Names::API_COUNT];
  #endif // MEASURE_CLRAPI_CALLS
  
      CompTimeInfo(unsigned byteCodeBytes);
  #endif
  };
  
  #ifdef FEATURE_JIT_METHOD_PERF
  
  #if MEASURE_CLRAPI_CALLS
  struct WrapICorJitInfo;
  #endif
  
  // This class summarizes the JIT time information over the course of a run: the number of methods compiled,
  // and the total and maximum timings.  (These are instances of the "CompTimeInfo" type described above).
  // The operation of adding a single method's timing to the summary may be performed concurrently by several
  // threads, so it is protected by a lock.
  // This class is intended to be used as a singleton type, with only a single instance.
  class CompTimeSummaryInfo
  {
      // This lock protects the fields of all CompTimeSummaryInfo(s) (of which we expect there to be one).
      static CritSecObject s_compTimeSummaryLock;
  
      int          m_numMethods;
      int          m_totMethods;
      CompTimeInfo m_total;
      CompTimeInfo m_maximum;
  
      int          m_numFilteredMethods;
      CompTimeInfo m_filtered;
  
      // This can use what ever data you want to determine if the value to be added
      // belongs in the filtered section (it's always included in the unfiltered section)
      bool IncludedInFilteredData(CompTimeInfo& info);
  
  public:
      // This is the unique CompTimeSummaryInfo object for this instance of the runtime.
      static CompTimeSummaryInfo s_compTimeSummary;
  
      CompTimeSummaryInfo()
          : m_numMethods(0), m_totMethods(0), m_total(0), m_maximum(0), m_numFilteredMethods(0), m_filtered(0)
      {
      }
  
      // Assumes that "info" is a completed CompTimeInfo for a compilation; adds it to the summary.
      // This is thread safe.
      void AddInfo(CompTimeInfo& info, bool includePhases);
  
      // Print the summary information to "f".
      // This is not thread-safe; assumed to be called by only one thread.
      void Print(FILE* f);
  };
  
  // A JitTimer encapsulates a CompTimeInfo for a single compilation. It also tracks the start of compilation,
  // and when the current phase started.  This is intended to be part of a Compilation object.
  //
  class JitTimer
  {
      unsigned __int64 m_start;         // Start of the compilation.
      unsigned __int64 m_curPhaseStart; // Start of the current phase.
  #if MEASURE_CLRAPI_CALLS
      unsigned __int64 m_CLRcallStart;   // Start of the current CLR API call (if any).
      unsigned __int64 m_CLRcallInvokes; // CLR API invokes under current outer so far
      unsigned __int64 m_CLRcallCycles;  // CLR API  cycles under current outer so far.
      int              m_CLRcallAPInum;  // The enum/index of the current CLR API call (or -1).
      static double    s_cyclesPerSec;   // Cached for speedier measurements
  #endif
  #ifdef DEBUG
      Phases m_lastPhase; // The last phase that was completed (or (Phases)-1 to start).
  #endif
      CompTimeInfo m_info; // The CompTimeInfo for this compilation.
  
      static CritSecObject s_csvLock; // Lock to protect the time log file.
      static FILE*         s_csvFile; // The time log file handle.
      void PrintCsvMethodStats(Compiler* comp);
  
  private:
      void* operator new(size_t);
      void* operator new[](size_t);
      void operator delete(void*);
      void operator delete[](void*);
  
  public:
      // Initialized the timer instance
      JitTimer(unsigned byteCodeSize);
  
      static JitTimer* Create(Compiler* comp, unsigned byteCodeSize)
      {
          return ::new (comp, CMK_Unknown) JitTimer(byteCodeSize);
      }
  
      static void PrintCsvHeader();
  
      // Ends the current phase (argument is for a redundant check).
      void EndPhase(Compiler* compiler, Phases phase);
  
  #if MEASURE_CLRAPI_CALLS
      // Start and end a timed CLR API call.
      void CLRApiCallEnter(unsigned apix);
      void CLRApiCallLeave(unsigned apix);
  #endif // MEASURE_CLRAPI_CALLS
  
      // Completes the timing of the current method, which is assumed to have "byteCodeBytes" bytes of bytecode,
      // and adds it to "sum".
      void Terminate(Compiler* comp, CompTimeSummaryInfo& sum, bool includePhases);
  
      // Attempts to query the cycle counter of the current thread.  If successful, returns "true" and sets
      // *cycles to the cycle counter value.  Otherwise, returns false and sets the "m_timerFailure" flag of
      // "m_info" to true.
      bool GetThreadCycles(unsigned __int64* cycles)
      {
          bool res = CycleTimer::GetThreadCyclesS(cycles);
          if (!res)
          {
              m_info.m_timerFailure = true;
          }
          return res;
      }
  
      static void Shutdown();
  };
  #endif // FEATURE_JIT_METHOD_PERF
  
  //------------------- Function/Funclet info -------------------------------
  enum FuncKind : BYTE
  {
      FUNC_ROOT,    // The main/root function (always id==0)
      FUNC_HANDLER, // a funclet associated with an EH handler (finally, fault, catch, filter handler)
      FUNC_FILTER,  // a funclet associated with an EH filter
      FUNC_COUNT
  };
  
  class emitLocation;
  
  struct FuncInfoDsc
  {
      FuncKind       funKind;
      BYTE           funFlags;   // Currently unused, just here for padding
      unsigned short funEHIndex; // index, into the ebd table, of innermost EH clause corresponding to this
                                 // funclet. It is only valid if funKind field indicates this is a
                                 // EH-related funclet: FUNC_HANDLER or FUNC_FILTER
  
  #if defined(TARGET_AMD64)
  
      // TODO-AMD64-Throughput: make the AMD64 info more like the ARM info to avoid having this large static array.
      emitLocation* startLoc;
      emitLocation* endLoc;
      emitLocation* coldStartLoc; // locations for the cold section, if there is one.
      emitLocation* coldEndLoc;
      UNWIND_INFO   unwindHeader;
      // Maximum of 255 UNWIND_CODE 'nodes' and then the unwind header. If there are an odd
      // number of codes, the VM or Zapper will 4-byte align the whole thing.
      BYTE     unwindCodes[offsetof(UNWIND_INFO, UnwindCode) + (0xFF * sizeof(UNWIND_CODE))];
      unsigned unwindCodeSlot;
  
  #elif defined(TARGET_X86)
  
      emitLocation* startLoc;
      emitLocation* endLoc;
      emitLocation* coldStartLoc; // locations for the cold section, if there is one.
      emitLocation* coldEndLoc;
  
  #elif defined(TARGET_ARMARCH)
  
      UnwindInfo  uwi;     // Unwind information for this function/funclet's hot  section
      UnwindInfo* uwiCold; // Unwind information for this function/funclet's cold section
                           //   Note: we only have a pointer here instead of the actual object,
                           //   to save memory in the JIT case (compared to the NGEN case),
                           //   where we don't have any cold section.
                           //   Note 2: we currently don't support hot/cold splitting in functions
                           //   with EH, so uwiCold will be NULL for all funclets.
  
      emitLocation* startLoc;
      emitLocation* endLoc;
      emitLocation* coldStartLoc; // locations for the cold section, if there is one.
      emitLocation* coldEndLoc;
  
  #endif // TARGET_ARMARCH
  
  #if defined(FEATURE_CFI_SUPPORT)
      jitstd::vector<CFI_CODE>* cfiCodes;
  #endif // FEATURE_CFI_SUPPORT
  
      // Eventually we may want to move rsModifiedRegsMask, lvaOutgoingArgSize, and anything else
      // that isn't shared between the main function body and funclets.
  };
  
  struct fgArgTabEntry
  {
      GenTreeCall::Use* use;     // Points to the argument's GenTreeCall::Use in gtCallArgs or gtCallThisArg.
      GenTreeCall::Use* lateUse; // Points to the argument's GenTreeCall::Use in gtCallLateArgs, if any.
  
      // Get the node that coresponds to this argument entry.
      // This is the "real" node and not a placeholder or setup node.
      GenTree* GetNode() const
      {
          return lateUse == nullptr ? use->GetNode() : lateUse->GetNode();
      }
  
      unsigned argNum; // The original argument number, also specifies the required argument evaluation order from the IL
  
  private:
      regNumberSmall regNums[MAX_ARG_REG_COUNT]; // The registers to use when passing this argument, set to REG_STK for
                                                 // arguments passed on the stack
  public:
      unsigned numRegs; // Count of number of registers that this argument uses.
                        // Note that on ARM, if we have a double hfa, this reflects the number
                        // of DOUBLE registers.
  
  #if defined(UNIX_AMD64_ABI)
      // Unix amd64 will split floating point types and integer types in structs
      // between floating point and general purpose registers. Keep track of that
      // information so we do not need to recompute it later.
      unsigned structIntRegs;
      unsigned structFloatRegs;
  #endif // UNIX_AMD64_ABI
  
  #if defined(DEBUG_ARG_SLOTS)
      // These fields were used to calculate stack size in stack slots for arguments
      // but now they are replaced by precise `m_byteOffset/m_byteSize` because of
      // arm64 apple abi requirements.
  
      // A slot is a pointer sized region in the OutArg area.
      unsigned slotNum;  // When an argument is passed in the OutArg area this is the slot number in the OutArg area
      unsigned numSlots; // Count of number of slots that this argument uses
  #endif                 // DEBUG_ARG_SLOTS
  
      // Return number of stack slots that this argument is taking.
      // TODO-Cleanup: this function does not align with arm64 apple model,
      // delete it. In most cases we just want to know if we it is using stack or not
      // but in some cases we are checking if it is a multireg arg, like:
      // `numRegs + GetStackSlotsNumber() > 1` that is harder to replace.
      //
      unsigned GetStackSlotsNumber() const
      {
          return roundUp(GetStackByteSize(), TARGET_POINTER_SIZE) / TARGET_POINTER_SIZE;
      }
  
  private:
      unsigned _lateArgInx; // index into gtCallLateArgs list; UINT_MAX if this is not a late arg.
  public:
      unsigned tmpNum; // the LclVar number if we had to force evaluation of this arg
  
      var_types argType; // The type used to pass this argument. This is generally the original argument type, but when a
                         // struct is passed as a scalar type, this is that type.
                         // Note that if a struct is passed by reference, this will still be the struct type.
  
      bool needTmp : 1;      // True when we force this argument's evaluation into a temp LclVar
      bool needPlace : 1;    // True when we must replace this argument with a placeholder node
      bool isTmp : 1;        // True when we setup a temp LclVar for this argument due to size issues with the struct
      bool processed : 1;    // True when we have decided the evaluation order for this argument in the gtCallLateArgs
      bool isBackFilled : 1; // True when the argument fills a register slot skipped due to alignment requirements of
                             // previous arguments.
      NonStandardArgKind nonStandardArgKind : 4; // The non-standard arg kind. Non-standard args are args that are forced
                                                 // to be in certain registers or on the stack, regardless of where they
                                                 // appear in the arg list.
      bool isStruct : 1;                         // True if this is a struct arg
      bool _isVararg : 1;                        // True if the argument is in a vararg context.
      bool passedByRef : 1;                      // True iff the argument is passed by reference.
  #if FEATURE_ARG_SPLIT
      bool _isSplit : 1; // True when this argument is split between the registers and OutArg area
  #endif                 // FEATURE_ARG_SPLIT
  #ifdef FEATURE_HFA_FIELDS_PRESENT
      CorInfoHFAElemType _hfaElemKind : 3; // What kind of an HFA this is (CORINFO_HFA_ELEM_NONE if it is not an HFA).
  #endif
      CorInfoHFAElemType GetHfaElemKind() const
      {
  #ifdef FEATURE_HFA_FIELDS_PRESENT
          return _hfaElemKind;
  #else
          NOWAY_MSG("GetHfaElemKind");
          return CORINFO_HFA_ELEM_NONE;
  #endif
      }
  
      void SetHfaElemKind(CorInfoHFAElemType elemKind)
      {
  #ifdef FEATURE_HFA_FIELDS_PRESENT
          _hfaElemKind = elemKind;
  #else
          NOWAY_MSG("SetHfaElemKind");
  #endif
      }
  
      bool isNonStandard() const
      {
          return nonStandardArgKind != NonStandardArgKind::None;
      }
  
      // Returns true if the IR node for this non-standarg arg is added by fgInitArgInfo.
      // In this case, it must be removed by GenTreeCall::ResetArgInfo.
      bool isNonStandardArgAddedLate() const
      {
          switch (static_cast<NonStandardArgKind>(nonStandardArgKind))
          {
              case NonStandardArgKind::None:
              case NonStandardArgKind::PInvokeFrame:
              case NonStandardArgKind::ShiftLow:
              case NonStandardArgKind::ShiftHigh:
              case NonStandardArgKind::FixedRetBuffer:
              case NonStandardArgKind::ValidateIndirectCallTarget:
                  return false;
              case NonStandardArgKind::WrapperDelegateCell:
              case NonStandardArgKind::VirtualStubCell:
              case NonStandardArgKind::PInvokeCookie:
              case NonStandardArgKind::PInvokeTarget:
              case NonStandardArgKind::R2RIndirectionCell:
                  return true;
              default:
                  unreached();
          }
      }
  
      bool isLateArg() const
      {
          bool isLate = (_lateArgInx != UINT_MAX);
          return isLate;
      }
  
      unsigned GetLateArgInx() const
      {
          assert(isLateArg());
          return _lateArgInx;
      }
      void SetLateArgInx(unsigned inx)
      {
          _lateArgInx = inx;
      }
      regNumber GetRegNum() const
      {
          return (regNumber)regNums[0];
      }
  
      regNumber GetOtherRegNum() const
      {
          return (regNumber)regNums[1];
      }
  
  #if defined(UNIX_AMD64_ABI)
      SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR structDesc;
  #endif
  
      void setRegNum(unsigned int i, regNumber regNum)
      {
          assert(i < MAX_ARG_REG_COUNT);
          regNums[i] = (regNumberSmall)regNum;
      }
      regNumber GetRegNum(unsigned int i)
      {
          assert(i < MAX_ARG_REG_COUNT);
          return (regNumber)regNums[i];
      }
  
      bool IsSplit() const
      {
  #if FEATURE_ARG_SPLIT
          return compFeatureArgSplit() && _isSplit;
  #else // FEATURE_ARG_SPLIT
          return false;
  #endif
      }
      void SetSplit(bool value)
      {
  #if FEATURE_ARG_SPLIT
          _isSplit = value;
  #endif
      }
  
      bool IsVararg() const
      {
          return compFeatureVarArg() && _isVararg;
      }
      void SetIsVararg(bool value)
      {
          if (compFeatureVarArg())
          {
              _isVararg = value;
          }
      }
  
      bool IsHfaArg() const
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              return IsHfa(GetHfaElemKind());
          }
          else
          {
              return false;
          }
      }
  
      bool IsHfaRegArg() const
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              return IsHfa(GetHfaElemKind()) && isPassedInRegisters();
          }
          else
          {
              return false;
          }
      }
  
      unsigned intRegCount() const
      {
  #if defined(UNIX_AMD64_ABI)
          if (this->isStruct)
          {
              return this->structIntRegs;
          }
  #endif // defined(UNIX_AMD64_ABI)
  
          if (!this->isPassedInFloatRegisters())
          {
              return this->numRegs;
          }
  
          return 0;
      }
  
      unsigned floatRegCount() const
      {
  #if defined(UNIX_AMD64_ABI)
          if (this->isStruct)
          {
              return this->structFloatRegs;
          }
  #endif // defined(UNIX_AMD64_ABI)
  
          if (this->isPassedInFloatRegisters())
          {
              return this->numRegs;
          }
  
          return 0;
      }
  
      // Get the number of bytes that this argument is occupying on the stack,
      // including padding up to the target pointer size for platforms
      // where a stack argument can't take less.
      unsigned GetStackByteSize() const
      {
          if (!IsSplit() && numRegs > 0)
          {
              return 0;
          }
  
          assert(!IsHfaArg() || !IsSplit());
  
          assert(GetByteSize() > TARGET_POINTER_SIZE * numRegs);
          const unsigned stackByteSize = GetByteSize() - TARGET_POINTER_SIZE * numRegs;
          return stackByteSize;
      }
  
      var_types GetHfaType() const
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              return HfaTypeFromElemKind(GetHfaElemKind());
          }
          else
          {
              return TYP_UNDEF;
          }
      }
  
      void SetHfaType(var_types type, unsigned hfaSlots)
      {
          if (GlobalJitOptions::compFeatureHfa)
          {
              if (type != TYP_UNDEF)
              {
                  // We must already have set the passing mode.
                  assert(numRegs != 0 || GetStackByteSize() != 0);
                  // We originally set numRegs according to the size of the struct, but if the size of the
                  // hfaType is not the same as the pointer size, we need to correct it.
                  // Note that hfaSlots is the number of registers we will use. For ARM, that is twice
                  // the number of "double registers".
                  unsigned numHfaRegs = hfaSlots;
  #ifdef TARGET_ARM
                  if (type == TYP_DOUBLE)
                  {
                      // Must be an even number of registers.
                      assert((numRegs & 1) == 0);
                      numHfaRegs = hfaSlots / 2;
                  }
  #endif // TARGET_ARM
  
                  if (!IsHfaArg())
                  {
                      // We haven't previously set this; do so now.
                      CorInfoHFAElemType elemKind = HfaElemKindFromType(type);
                      SetHfaElemKind(elemKind);
                      // Ensure we've allocated enough bits.
                      assert(GetHfaElemKind() == elemKind);
                      if (isPassedInRegisters())
                      {
                          numRegs = numHfaRegs;
                      }
                  }
                  else
                  {
                      // We've already set this; ensure that it's consistent.
                      if (isPassedInRegisters())
                      {
                          assert(numRegs == numHfaRegs);
                      }
                      assert(type == HfaTypeFromElemKind(GetHfaElemKind()));
                  }
              }
          }
      }
  
  #ifdef TARGET_ARM
      void SetIsBackFilled(bool backFilled)
      {
          isBackFilled = backFilled;
      }
  
      bool IsBackFilled() const
      {
          return isBackFilled;
      }
  #else  // !TARGET_ARM
      void SetIsBackFilled(bool backFilled)
      {
      }
  
      bool IsBackFilled() const
      {
          return false;
      }
  #endif // !TARGET_ARM
  
      bool isPassedInRegisters() const
      {
          return !IsSplit() && (numRegs != 0);
      }
  
      bool isPassedInFloatRegisters() const
      {
  #ifdef TARGET_X86
          return false;
  #else
          return isValidFloatArgReg(GetRegNum());
  #endif
      }
  
      // Can we replace the struct type of this node with a primitive type for argument passing?
      bool TryPassAsPrimitive() const
      {
          return !IsSplit() && ((numRegs == 1) || (m_byteSize <= TARGET_POINTER_SIZE));
      }
  
  #if defined(DEBUG_ARG_SLOTS)
      // Returns the number of "slots" used, where for this purpose a
      // register counts as a slot.
      unsigned getSlotCount() const
      {
          if (isBackFilled)
          {
              assert(isPassedInRegisters());
              assert(numRegs == 1);
          }
          else if (GetRegNum() == REG_STK)
          {
              assert(!isPassedInRegisters());
              assert(numRegs == 0);
          }
          else
          {
              assert(numRegs > 0);
          }
          return numSlots + numRegs;
      }
  #endif
  
  #if defined(DEBUG_ARG_SLOTS)
      // Returns the size as a multiple of pointer-size.
      // For targets without HFAs, this is the same as getSlotCount().
      unsigned getSize() const
      {
          unsigned size = getSlotCount();
          if (GlobalJitOptions::compFeatureHfa)
          {
              if (IsHfaRegArg())
              {
  #ifdef TARGET_ARM
                  // We counted the number of regs, but if they are DOUBLE hfa regs we have to double the size.
                  if (GetHfaType() == TYP_DOUBLE)
                  {
                      assert(!IsSplit());
                      size <<= 1;
                  }
  #elif defined(TARGET_ARM64)
                  // We counted the number of regs, but if they are FLOAT hfa regs we have to halve the size,
                  // or if they are SIMD16 vector hfa regs we have to double the size.
                  if (GetHfaType() == TYP_FLOAT)
                  {
                      // Round up in case of odd HFA count.
                      size = (size + 1) >> 1;
                  }
  #ifdef FEATURE_SIMD
                  else if (GetHfaType() == TYP_SIMD16)
                  {
                      size <<= 1;
                  }
  #endif // FEATURE_SIMD
  #endif // TARGET_ARM64
              }
          }
          return size;
      }
  
  #endif // DEBUG_ARG_SLOTS
  
  private:
      unsigned m_byteOffset;
  
      // byte size that this argument takes including the padding after.
      // For example, 1-byte arg on x64 with 8-byte alignment
      // will have `m_byteSize == 8`, the same arg on apple arm64 will have `m_byteSize == 1`.
      unsigned m_byteSize;
  
      unsigned m_byteAlignment; // usually 4 or 8 bytes (slots/registers).
  
  public:
      void SetByteOffset(unsigned byteOffset)
      {
          DEBUG_ARG_SLOTS_ASSERT(byteOffset / TARGET_POINTER_SIZE == slotNum);
          m_byteOffset = byteOffset;
      }
  
      unsigned GetByteOffset() const
      {
          DEBUG_ARG_SLOTS_ASSERT(m_byteOffset / TARGET_POINTER_SIZE == slotNum);
          return m_byteOffset;
      }
  
      void SetByteSize(unsigned byteSize, bool isStruct, bool isFloatHfa)
      {
  
          unsigned roundedByteSize;
          if (compMacOsArm64Abi())
          {
              // Only struct types need extension or rounding to pointer size, but HFA<float> does not.
              if (isStruct && !isFloatHfa)
              {
                  roundedByteSize = roundUp(byteSize, TARGET_POINTER_SIZE);
              }
              else
              {
                  roundedByteSize = byteSize;
              }
          }
          else
          {
              roundedByteSize = roundUp(byteSize, TARGET_POINTER_SIZE);
          }
  
  #if !defined(TARGET_ARM)
          // Arm32 could have a struct with 8 byte alignment
          // which rounded size % 8 is not 0.
          assert(m_byteAlignment != 0);
          assert(roundedByteSize % m_byteAlignment == 0);
  #endif // TARGET_ARM
  
  #if defined(DEBUG_ARG_SLOTS)
          if (!compMacOsArm64Abi() && !isStruct)
          {
              assert(roundedByteSize == getSlotCount() * TARGET_POINTER_SIZE);
          }
  #endif
          m_byteSize = roundedByteSize;
      }
  
      unsigned GetByteSize() const
      {
          return m_byteSize;
      }
  
      void SetByteAlignment(unsigned byteAlignment)
      {
          m_byteAlignment = byteAlignment;
      }
  
      unsigned GetByteAlignment() const
      {
          return m_byteAlignment;
      }
  
      // Set the register numbers for a multireg argument.
      // There's nothing to do on x64/Ux because the structDesc has already been used to set the
      // register numbers.
      void SetMultiRegNums()
      {
  #if FEATURE_MULTIREG_ARGS && !defined(UNIX_AMD64_ABI)
          if (numRegs == 1)
          {
              return;
          }
  
          regNumber argReg = GetRegNum(0);
  #ifdef TARGET_ARM
          unsigned int regSize = (GetHfaType() == TYP_DOUBLE) ? 2 : 1;
  #else
          unsigned int regSize = 1;
  #endif
  
          if (numRegs > MAX_ARG_REG_COUNT)
              NO_WAY("Multireg argument exceeds the maximum length");
  
          for (unsigned int regIndex = 1; regIndex < numRegs; regIndex++)
          {
              argReg = (regNumber)(argReg + regSize);
              setRegNum(regIndex, argReg);
          }
  #endif // FEATURE_MULTIREG_ARGS && !defined(UNIX_AMD64_ABI)
      }
  
  #ifdef DEBUG
      // Check that the value of 'isStruct' is consistent.
      // A struct arg must be one of the following:
      // - A node of struct type,
      // - A GT_FIELD_LIST, or
      // - A node of a scalar type, passed in a single register or slot
      //   (or two slots in the case of a struct pass on the stack as TYP_DOUBLE).
      //
      void checkIsStruct() const
      {
          GenTree* node = GetNode();
          if (isStruct)
          {
              if (!varTypeIsStruct(node) && !node->OperIs(GT_FIELD_LIST))
              {
                  // This is the case where we are passing a struct as a primitive type.
                  // On most targets, this is always a single register or slot.
                  // However, on ARM this could be two slots if it is TYP_DOUBLE.
                  bool isPassedAsPrimitiveType =
                      ((numRegs == 1) || ((numRegs == 0) && (GetByteSize() <= TARGET_POINTER_SIZE)));
  #ifdef TARGET_ARM
                  if (!isPassedAsPrimitiveType)
                  {
                      if (node->TypeGet() == TYP_DOUBLE && numRegs == 0 && (numSlots == 2))
                      {
                          isPassedAsPrimitiveType = true;
                      }
                  }
  #endif // TARGET_ARM
                  assert(isPassedAsPrimitiveType);
              }
          }
          else
          {
              assert(!varTypeIsStruct(node));
          }
      }
  
      void Dump() const;
  #endif
  };
  
  //-------------------------------------------------------------------------
  //
  //  The class fgArgInfo is used to handle the arguments
  //  when morphing a GT_CALL node.
  //
  
  class fgArgInfo
  {
      Compiler*    compiler; // Back pointer to the compiler instance so that we can allocate memory
      GenTreeCall* callTree; // Back pointer to the GT_CALL node for this fgArgInfo
      unsigned     argCount; // Updatable arg count value
  #if defined(DEBUG_ARG_SLOTS)
      unsigned nextSlotNum; // Updatable slot count value
  #endif
      unsigned nextStackByteOffset;
      unsigned stkLevel; // Stack depth when we make this call (for x86)
  
  #if defined(UNIX_X86_ABI)
      bool     alignmentDone; // Updateable flag, set to 'true' after we've done any required alignment.
      unsigned stkSizeBytes;  // Size of stack used by this call, in bytes. Calculated during fgMorphArgs().
      unsigned padStkAlign;   // Stack alignment in bytes required before arguments are pushed for this call.
                              // Computed dynamically during codegen, based on stkSizeBytes and the current
                              // stack level (genStackLevel) when the first stack adjustment is made for
                              // this call.
  #endif
  
  #if FEATURE_FIXED_OUT_ARGS
      unsigned outArgSize; // Size of the out arg area for the call, will be at least MIN_ARG_AREA_FOR_CALL
  #endif
  
      unsigned        argTableSize; // size of argTable array (equal to the argCount when done with fgMorphArgs)
      bool            hasRegArgs;   // true if we have one or more register arguments
      bool            hasStackArgs; // true if we have one or more stack arguments
      bool            argsComplete; // marker for state
      bool            argsSorted;   // marker for state
      bool            needsTemps;   // one or more arguments must be copied to a temp by EvalArgsToTemps
      fgArgTabEntry** argTable;     // variable sized array of per argument descrption: (i.e. argTable[argTableSize])
  
  private:
      void AddArg(fgArgTabEntry* curArgTabEntry);
  
  public:
      fgArgInfo(Compiler* comp, GenTreeCall* call, unsigned argCount);
      fgArgInfo(GenTreeCall* newCall, GenTreeCall* oldCall);
  
      fgArgTabEntry* AddRegArg(unsigned          argNum,
                               GenTree*          node,
                               GenTreeCall::Use* use,
                               regNumber         regNum,
                               unsigned          numRegs,
                               unsigned          byteSize,
                               unsigned          byteAlignment,
                               bool              isStruct,
                               bool              isFloatHfa,
                               bool              isVararg = false);
  
  #ifdef UNIX_AMD64_ABI
      fgArgTabEntry* AddRegArg(unsigned                                                         argNum,
                               GenTree*                                                         node,
                               GenTreeCall::Use*                                                use,
                               regNumber                                                        regNum,
                               unsigned                                                         numRegs,
                               unsigned                                                         byteSize,
                               unsigned                                                         byteAlignment,
                               const bool                                                       isStruct,
                               const bool                                                       isFloatHfa,
                               const bool                                                       isVararg,
                               const regNumber                                                  otherRegNum,
                               const unsigned                                                   structIntRegs,
                               const unsigned                                                   structFloatRegs,
                               const SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR* const structDescPtr = nullptr);
  #endif // UNIX_AMD64_ABI
  
      fgArgTabEntry* AddStkArg(unsigned          argNum,
                               GenTree*          node,
                               GenTreeCall::Use* use,
                               unsigned          numSlots,
                               unsigned          byteSize,
                               unsigned          byteAlignment,
                               bool              isStruct,
                               bool              isFloatHfa,
                               bool              isVararg = false);
  
      void RemorphReset();
      void UpdateRegArg(fgArgTabEntry* argEntry, GenTree* node, bool reMorphing);
      void UpdateStkArg(fgArgTabEntry* argEntry, GenTree* node, bool reMorphing);
  
      void SplitArg(unsigned argNum, unsigned numRegs, unsigned numSlots);
  
      void EvalToTmp(fgArgTabEntry* curArgTabEntry, unsigned tmpNum, GenTree* newNode);
  
      void ArgsComplete();
  
      void SortArgs();
  
      void EvalArgsToTemps();
  
      unsigned ArgCount() const
      {
          return argCount;
      }
      fgArgTabEntry** ArgTable() const
      {
          return argTable;
      }
  
  #if defined(DEBUG_ARG_SLOTS)
      unsigned GetNextSlotNum() const
      {
          return nextSlotNum;
      }
  #endif
  
      unsigned GetNextSlotByteOffset() const
      {
          return nextStackByteOffset;
      }
  
      bool HasRegArgs() const
      {
          return hasRegArgs;
      }
      bool NeedsTemps() const
      {
          return needsTemps;
      }
      bool HasStackArgs() const
      {
          return hasStackArgs;
      }
      bool AreArgsComplete() const
      {
          return argsComplete;
      }
  #if FEATURE_FIXED_OUT_ARGS
      unsigned GetOutArgSize() const
      {
          return outArgSize;
      }
      void SetOutArgSize(unsigned newVal)
      {
          outArgSize = newVal;
      }
  #endif // FEATURE_FIXED_OUT_ARGS
  
  #if defined(UNIX_X86_ABI)
      void ComputeStackAlignment(unsigned curStackLevelInBytes)
      {
          padStkAlign = AlignmentPad(curStackLevelInBytes, STACK_ALIGN);
      }
  
      unsigned GetStkAlign() const
      {
          return padStkAlign;
      }
  
      void SetStkSizeBytes(unsigned newStkSizeBytes)
      {
          stkSizeBytes = newStkSizeBytes;
      }
  
      unsigned GetStkSizeBytes() const
      {
          return stkSizeBytes;
      }
  
      bool IsStkAlignmentDone() const
      {
          return alignmentDone;
      }
  
      void SetStkAlignmentDone()
      {
          alignmentDone = true;
      }
  #endif // defined(UNIX_X86_ABI)
  
      // Get the fgArgTabEntry for the arg at position argNum.
      fgArgTabEntry* GetArgEntry(unsigned argNum, bool reMorphing = true) const
      {
          fgArgTabEntry* curArgTabEntry = nullptr;
  
          if (!reMorphing)
          {
              // The arg table has not yet been sorted.
              curArgTabEntry = argTable[argNum];
              assert(curArgTabEntry->argNum == argNum);
              return curArgTabEntry;
          }
  
          for (unsigned i = 0; i < argCount; i++)
          {
              curArgTabEntry = argTable[i];
              if (curArgTabEntry->argNum == argNum)
              {
                  return curArgTabEntry;
              }
          }
          noway_assert(!"GetArgEntry: argNum not found");
          return nullptr;
      }
      void SetNeedsTemps()
      {
          needsTemps = true;
      }
  
      // Get the node for the arg at position argIndex.
      // Caller must ensure that this index is a valid arg index.
      GenTree* GetArgNode(unsigned argIndex) const
      {
          return GetArgEntry(argIndex)->GetNode();
      }
  
      void Dump(Compiler* compiler) const;
  };
  
  #ifdef DEBUG
  // XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  // We have the ability to mark source expressions with "Test Labels."
  // These drive assertions within the JIT, or internal JIT testing.  For example, we could label expressions
  // that should be CSE defs, and other expressions that should uses of those defs, with a shared label.
  
  enum TestLabel // This must be kept identical to System.Runtime.CompilerServices.JitTestLabel.TestLabel.
  {
      TL_SsaName,
      TL_VN,        // Defines a "VN equivalence class".  (For full VN, including exceptions thrown).
      TL_VNNorm,    // Like above, but uses the non-exceptional value of the expression.
      TL_CSE_Def,   //  This must be identified in the JIT as a CSE def
      TL_CSE_Use,   //  This must be identified in the JIT as a CSE use
      TL_LoopHoist, // Expression must (or must not) be hoisted out of the loop.
  };
  
  struct TestLabelAndNum
  {
      TestLabel m_tl;
      ssize_t   m_num;
  
      TestLabelAndNum() : m_tl(TestLabel(0)), m_num(0)
      {
      }
  };
  
  typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, TestLabelAndNum> NodeToTestDataMap;
  
  // XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  #endif // DEBUG
  
  //-------------------------------------------------------------------------
  // LoopFlags: flags for the loop table.
  //
  enum LoopFlags : unsigned short
  {
      LPFLG_EMPTY = 0,
  
      // LPFLG_UNUSED  = 0x0001,
      // LPFLG_UNUSED  = 0x0002,
      LPFLG_ITER = 0x0004, // loop of form: for (i = icon or lclVar; test_condition(); i++)
      // LPFLG_UNUSED    = 0x0008,
  
      LPFLG_CONTAINS_CALL = 0x0010, // If executing the loop body *may* execute a call
      LPFLG_VAR_INIT      = 0x0020, // iterator is initialized with a local var (var # found in lpVarInit)
      LPFLG_CONST_INIT    = 0x0040, // iterator is initialized with a constant (found in lpConstInit)
      LPFLG_SIMD_LIMIT    = 0x0080, // iterator is compared with vector element count (found in lpConstLimit)
  
      LPFLG_VAR_LIMIT    = 0x0100, // iterator is compared with a local var (var # found in lpVarLimit)
      LPFLG_CONST_LIMIT  = 0x0200, // iterator is compared with a constant (found in lpConstLimit)
      LPFLG_ARRLEN_LIMIT = 0x0400, // iterator is compared with a.len or a[i].len (found in lpArrLenLimit)
      LPFLG_HAS_PREHEAD  = 0x0800, // lpHead is known to be a preHead for this loop
  
      LPFLG_REMOVED     = 0x1000, // has been removed from the loop table (unrolled or optimized away)
      LPFLG_DONT_UNROLL = 0x2000, // do not unroll this loop
      LPFLG_ASGVARS_YES = 0x4000, // "lpAsgVars" has been computed
      LPFLG_ASGVARS_INC = 0x8000, // "lpAsgVars" is incomplete -- vars beyond those representable in an AllVarSet
                                  // type are assigned to.
  };
  
  inline constexpr LoopFlags operator~(LoopFlags a)
  {
      return (LoopFlags)(~(unsigned short)a);
  }
  
  inline constexpr LoopFlags operator|(LoopFlags a, LoopFlags b)
  {
      return (LoopFlags)((unsigned short)a | (unsigned short)b);
  }
  
  inline constexpr LoopFlags operator&(LoopFlags a, LoopFlags b)
  {
      return (LoopFlags)((unsigned short)a & (unsigned short)b);
  }
  
  inline LoopFlags& operator|=(LoopFlags& a, LoopFlags b)
  {
      return a = (LoopFlags)((unsigned short)a | (unsigned short)b);
  }
  
  inline LoopFlags& operator&=(LoopFlags& a, LoopFlags b)
  {
      return a = (LoopFlags)((unsigned short)a & (unsigned short)b);
  }
  
  //  The following holds information about instr offsets in terms of generated code.
  
  enum class IPmappingDscKind
  {
      Prolog,    // The mapping represents the start of a prolog.
      Epilog,    // The mapping represents the start of an epilog.
      NoMapping, // This does not map to any IL offset.
      Normal,    // The mapping maps to an IL offset.
  };
  
  struct IPmappingDsc
  {
      emitLocation     ipmdNativeLoc; // the emitter location of the native code corresponding to the IL offset
      IPmappingDscKind ipmdKind;      // The kind of mapping
      ILLocation       ipmdLoc;       // The location for normal mappings
      bool             ipmdIsLabel;   // Can this code be a branch label?
  };
  
  struct PreciseIPMapping
  {
      emitLocation nativeLoc;
      DebugInfo    debugInfo;
  };
  
  /*
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XX                                                                           XX
  XX   The big guy. The sections are currently organized as :                  XX
  XX                                                                           XX
  XX    o  GenTree and BasicBlock                                              XX
  XX    o  LclVarsInfo                                                         XX
  XX    o  Importer                                                            XX
  XX    o  FlowGraph                                                           XX
  XX    o  Optimizer                                                           XX
  XX    o  RegAlloc                                                            XX
  XX    o  EEInterface                                                         XX
  XX    o  TempsInfo                                                           XX
  XX    o  RegSet                                                              XX
  XX    o  GCInfo                                                              XX
  XX    o  Instruction                                                         XX
  XX    o  ScopeInfo                                                           XX
  XX    o  PrologScopeInfo                                                     XX
  XX    o  CodeGenerator                                                       XX
  XX    o  UnwindInfo                                                          XX
  XX    o  Compiler                                                            XX
  XX    o  typeInfo                                                            XX
  XX                                                                           XX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  */
  
  struct HWIntrinsicInfo;
  
  class Compiler
  {
      friend class emitter;
      friend class UnwindInfo;
      friend class UnwindFragmentInfo;
      friend class UnwindEpilogInfo;
      friend class JitTimer;
      friend class LinearScan;
      friend class fgArgInfo;
      friend class Rationalizer;
      friend class Phase;
      friend class Lowering;
      friend class CSE_DataFlow;
      friend class CSE_Heuristic;
      friend class CodeGenInterface;
      friend class CodeGen;
      friend class LclVarDsc;
      friend class TempDsc;
      friend class LIR;
      friend class ObjectAllocator;
      friend class LocalAddressVisitor;
      friend struct GenTree;
      friend class MorphInitBlockHelper;
      friend class MorphCopyBlockHelper;
  
  #ifdef FEATURE_HW_INTRINSICS
      friend struct HWIntrinsicInfo;
  #endif // FEATURE_HW_INTRINSICS
  
  #ifndef TARGET_64BIT
      friend class DecomposeLongs;
  #endif // !TARGET_64BIT
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX  Misc structs definitions                                                 XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      hashBvGlobalData hbvGlobalData; // Used by the hashBv bitvector package.
  
  #ifdef DEBUG
      bool verbose;
      bool verboseTrees;
      bool shouldUseVerboseTrees();
      bool asciiTrees; // If true, dump trees using only ASCII characters
      bool shouldDumpASCIITrees();
      bool verboseSsa; // If true, produce especially verbose dump output in SSA construction.
      bool shouldUseVerboseSsa();
      bool treesBeforeAfterMorph; // If true, print trees before/after morphing (paired by an intra-compilation id:
      int  morphNum;              // This counts the the trees that have been morphed, allowing us to label each uniquely.
      bool doExtraSuperPmiQueries;
      void makeExtraStructQueries(CORINFO_CLASS_HANDLE structHandle, int level); // Make queries recursively 'level' deep.
  
      const char* VarNameToStr(VarName name)
      {
          return name;
      }
  
      DWORD expensiveDebugCheckLevel;
  #endif
  
  #if FEATURE_MULTIREG_RET
      GenTree* impAssignMultiRegTypeToVar(GenTree*             op,
                                          CORINFO_CLASS_HANDLE hClass DEBUGARG(CorInfoCallConvExtension callConv));
  #endif // FEATURE_MULTIREG_RET
  
  #ifdef TARGET_X86
      bool isTrivialPointerSizedStruct(CORINFO_CLASS_HANDLE clsHnd) const;
  #endif // TARGET_X86
  
      //-------------------------------------------------------------------------
      // Functions to handle homogeneous floating-point aggregates (HFAs) in ARM/ARM64.
      // HFAs are one to four element structs where each element is the same
      // type, either all float or all double. We handle HVAs (one to four elements of
      // vector types) uniformly with HFAs. HFAs are treated specially
      // in the ARM/ARM64 Procedure Call Standards, specifically, they are passed in
      // floating-point registers instead of the general purpose registers.
      //
  
      bool IsHfa(CORINFO_CLASS_HANDLE hClass);
      bool IsHfa(GenTree* tree);
  
      var_types GetHfaType(GenTree* tree);
      unsigned GetHfaCount(GenTree* tree);
  
      var_types GetHfaType(CORINFO_CLASS_HANDLE hClass);
      unsigned GetHfaCount(CORINFO_CLASS_HANDLE hClass);
  
      bool IsMultiRegReturnedType(CORINFO_CLASS_HANDLE hClass, CorInfoCallConvExtension callConv);
  
      //-------------------------------------------------------------------------
      // The following is used for validating format of EH table
      //
  
      struct EHNodeDsc;
      typedef struct EHNodeDsc* pEHNodeDsc;
  
      EHNodeDsc* ehnTree; // root of the tree comprising the EHnodes.
      EHNodeDsc* ehnNext; // root of the tree comprising the EHnodes.
  
      struct EHNodeDsc
      {
          enum EHBlockType
          {
              TryNode,
              FilterNode,
              HandlerNode,
              FinallyNode,
              FaultNode
          };
  
          EHBlockType ehnBlockType;   // kind of EH block
          IL_OFFSET   ehnStartOffset; // IL offset of start of the EH block
          IL_OFFSET ehnEndOffset; // IL offset past end of the EH block. (TODO: looks like verInsertEhNode() sets this to
                                  // the last IL offset, not "one past the last one", i.e., the range Start to End is
                                  // inclusive).
          pEHNodeDsc ehnNext;     // next (non-nested) block in sequential order
          pEHNodeDsc ehnChild;    // leftmost nested block
          union {
              pEHNodeDsc ehnTryNode;     // for filters and handlers, the corresponding try node
              pEHNodeDsc ehnHandlerNode; // for a try node, the corresponding handler node
          };
          pEHNodeDsc ehnFilterNode; // if this is a try node and has a filter, otherwise 0
          pEHNodeDsc ehnEquivalent; // if blockType=tryNode, start offset and end offset is same,
  
          void ehnSetTryNodeType()
          {
              ehnBlockType = TryNode;
          }
          void ehnSetFilterNodeType()
          {
              ehnBlockType = FilterNode;
          }
          void ehnSetHandlerNodeType()
          {
              ehnBlockType = HandlerNode;
          }
          void ehnSetFinallyNodeType()
          {
              ehnBlockType = FinallyNode;
          }
          void ehnSetFaultNodeType()
          {
              ehnBlockType = FaultNode;
          }
  
          bool ehnIsTryBlock()
          {
              return ehnBlockType == TryNode;
          }
          bool ehnIsFilterBlock()
          {
              return ehnBlockType == FilterNode;
          }
          bool ehnIsHandlerBlock()
          {
              return ehnBlockType == HandlerNode;
          }
          bool ehnIsFinallyBlock()
          {
              return ehnBlockType == FinallyNode;
          }
          bool ehnIsFaultBlock()
          {
              return ehnBlockType == FaultNode;
          }
  
          // returns true if there is any overlap between the two nodes
          static bool ehnIsOverlap(pEHNodeDsc node1, pEHNodeDsc node2)
          {
              if (node1->ehnStartOffset < node2->ehnStartOffset)
              {
                  return (node1->ehnEndOffset >= node2->ehnStartOffset);
              }
              else
              {
                  return (node1->ehnStartOffset <= node2->ehnEndOffset);
              }
          }
  
          // fails with BADCODE if inner is not completely nested inside outer
          static bool ehnIsNested(pEHNodeDsc inner, pEHNodeDsc outer)
          {
              return ((inner->ehnStartOffset >= outer->ehnStartOffset) && (inner->ehnEndOffset <= outer->ehnEndOffset));
          }
      };
  
  //-------------------------------------------------------------------------
  // Exception handling functions
  //
  
  #if !defined(FEATURE_EH_FUNCLETS)
  
      bool ehNeedsShadowSPslots()
      {
          return (info.compXcptnsCount || opts.compDbgEnC);
      }
  
      // 0 for methods with no EH
      // 1 for methods with non-nested EH, or where only the try blocks are nested
      // 2 for a method with a catch within a catch
      // etc.
      unsigned ehMaxHndNestingCount;
  
  #endif // !FEATURE_EH_FUNCLETS
  
      static bool jitIsBetween(unsigned value, unsigned start, unsigned end);
      static bool jitIsBetweenInclusive(unsigned value, unsigned start, unsigned end);
  
      bool bbInCatchHandlerILRange(BasicBlock* blk);
      bool bbInFilterILRange(BasicBlock* blk);
      bool bbInTryRegions(unsigned regionIndex, BasicBlock* blk);
      bool bbInExnFlowRegions(unsigned regionIndex, BasicBlock* blk);
      bool bbInHandlerRegions(unsigned regionIndex, BasicBlock* blk);
      bool bbInCatchHandlerRegions(BasicBlock* tryBlk, BasicBlock* hndBlk);
      unsigned short bbFindInnermostCommonTryRegion(BasicBlock* bbOne, BasicBlock* bbTwo);
  
      unsigned short bbFindInnermostTryRegionContainingHandlerRegion(unsigned handlerIndex);
      unsigned short bbFindInnermostHandlerRegionContainingTryRegion(unsigned tryIndex);
  
      // Returns true if "block" is the start of a try region.
      bool bbIsTryBeg(BasicBlock* block);
  
      // Returns true if "block" is the start of a handler or filter region.
      bool bbIsHandlerBeg(BasicBlock* block);
  
      // Returns true iff "block" is where control flows if an exception is raised in the
      // try region, and sets "*regionIndex" to the index of the try for the handler.
      // Differs from "IsHandlerBeg" in the case of filters, where this is true for the first
      // block of the filter, but not for the filter's handler.
      bool bbIsExFlowBlock(BasicBlock* block, unsigned* regionIndex);
  
      bool ehHasCallableHandlers();
  
      // Return the EH descriptor for the given region index.
      EHblkDsc* ehGetDsc(unsigned regionIndex);
  
      // Return the EH index given a region descriptor.
      unsigned ehGetIndex(EHblkDsc* ehDsc);
  
      // Return the EH descriptor index of the enclosing try, for the given region index.
      unsigned ehGetEnclosingTryIndex(unsigned regionIndex);
  
      // Return the EH descriptor index of the enclosing handler, for the given region index.
      unsigned ehGetEnclosingHndIndex(unsigned regionIndex);
  
      // Return the EH descriptor for the most nested 'try' region this BasicBlock is a member of (or nullptr if this
      // block is not in a 'try' region).
      EHblkDsc* ehGetBlockTryDsc(BasicBlock* block);
  
      // Return the EH descriptor for the most nested filter or handler region this BasicBlock is a member of (or nullptr
      // if this block is not in a filter or handler region).
      EHblkDsc* ehGetBlockHndDsc(BasicBlock* block);
  
      // Return the EH descriptor for the most nested region that may handle exceptions raised in this BasicBlock (or
      // nullptr if this block's exceptions propagate to caller).
      EHblkDsc* ehGetBlockExnFlowDsc(BasicBlock* block);
  
      EHblkDsc* ehIsBlockTryLast(BasicBlock* block);
      EHblkDsc* ehIsBlockHndLast(BasicBlock* block);
      bool ehIsBlockEHLast(BasicBlock* block);
  
      bool ehBlockHasExnFlowDsc(BasicBlock* block);
  
      // Return the region index of the most nested EH region this block is in.
      unsigned ehGetMostNestedRegionIndex(BasicBlock* block, bool* inTryRegion);
  
      // Find the true enclosing try index, ignoring 'mutual protect' try. Uses IL ranges to check.
      unsigned ehTrueEnclosingTryIndexIL(unsigned regionIndex);
  
      // Return the index of the most nested enclosing region for a particular EH region. Returns NO_ENCLOSING_INDEX
      // if there is no enclosing region. If the returned index is not NO_ENCLOSING_INDEX, then '*inTryRegion'
      // is set to 'true' if the enclosing region is a 'try', or 'false' if the enclosing region is a handler.
      // (It can never be a filter.)
      unsigned ehGetEnclosingRegionIndex(unsigned regionIndex, bool* inTryRegion);
  
      // A block has been deleted. Update the EH table appropriately.
      void ehUpdateForDeletedBlock(BasicBlock* block);
  
      // Determine whether a block can be deleted while preserving the EH normalization rules.
      bool ehCanDeleteEmptyBlock(BasicBlock* block);
  
      // Update the 'last' pointers in the EH table to reflect new or deleted blocks in an EH region.
      void ehUpdateLastBlocks(BasicBlock* oldLast, BasicBlock* newLast);
  
      // For a finally handler, find the region index that the BBJ_CALLFINALLY lives in that calls the handler,
      // or NO_ENCLOSING_INDEX if the BBJ_CALLFINALLY lives in the main function body. Normally, the index
      // is the same index as the handler (and the BBJ_CALLFINALLY lives in the 'try' region), but for AMD64 the
      // BBJ_CALLFINALLY lives in the enclosing try or handler region, whichever is more nested, or the main function
      // body. If the returned index is not NO_ENCLOSING_INDEX, then '*inTryRegion' is set to 'true' if the
      // BBJ_CALLFINALLY lives in the returned index's 'try' region, or 'false' if lives in the handler region. (It never
      // lives in a filter.)
      unsigned ehGetCallFinallyRegionIndex(unsigned finallyIndex, bool* inTryRegion);
  
      // Find the range of basic blocks in which all BBJ_CALLFINALLY will be found that target the 'finallyIndex' region's
      // handler. Set begBlk to the first block, and endBlk to the block after the last block of the range
      // (nullptr if the last block is the last block in the program).
      // Precondition: 'finallyIndex' is the EH region of a try/finally clause.
      void ehGetCallFinallyBlockRange(unsigned finallyIndex, BasicBlock** begBlk, BasicBlock** endBlk);
  
  #ifdef DEBUG
      // Given a BBJ_CALLFINALLY block and the EH region index of the finally it is calling, return
      // 'true' if the BBJ_CALLFINALLY is in the correct EH region.
      bool ehCallFinallyInCorrectRegion(BasicBlock* blockCallFinally, unsigned finallyIndex);
  #endif // DEBUG
  
  #if defined(FEATURE_EH_FUNCLETS)
      // Do we need a PSPSym in the main function? For codegen purposes, we only need one
      // if there is a filter that protects a region with a nested EH clause (such as a
      // try/catch nested in the 'try' body of a try/filter/filter-handler). See
      // genFuncletProlog() for more details. However, the VM seems to use it for more
      // purposes, maybe including debugging. Until we are sure otherwise, always create
      // a PSPSym for functions with any EH.
      bool ehNeedsPSPSym() const
      {
  #ifdef TARGET_X86
          return false;
  #else  // TARGET_X86
          return compHndBBtabCount > 0;
  #endif // TARGET_X86
      }
  
      bool     ehAnyFunclets();  // Are there any funclets in this function?
      unsigned ehFuncletCount(); // Return the count of funclets in the function
  
      unsigned bbThrowIndex(BasicBlock* blk); // Get the index to use as the cache key for sharing throw blocks
  
  #else  // !FEATURE_EH_FUNCLETS
  
      bool ehAnyFunclets()
      {
          return false;
      }
      unsigned ehFuncletCount()
      {
          return 0;
      }
  
      unsigned bbThrowIndex(BasicBlock* blk)
      {
          return blk->bbTryIndex;
      } // Get the index to use as the cache key for sharing throw blocks
  #endif // !FEATURE_EH_FUNCLETS
  
      // Returns a flowList representing the "EH predecessors" of "blk".  These are the normal predecessors of
      // "blk", plus one special case: if "blk" is the first block of a handler, considers the predecessor(s) of the first
      // first block of the corresponding try region to be "EH predecessors".  (If there is a single such predecessor,
      // for example, we want to consider that the immediate dominator of the catch clause start block, so it's
      // convenient to also consider it a predecessor.)
      flowList* BlockPredsWithEH(BasicBlock* blk);
  
      // This table is useful for memoization of the method above.
      typedef JitHashTable<BasicBlock*, JitPtrKeyFuncs<BasicBlock>, flowList*> BlockToFlowListMap;
      BlockToFlowListMap* m_blockToEHPreds;
      BlockToFlowListMap* GetBlockToEHPreds()
      {
          if (m_blockToEHPreds == nullptr)
          {
              m_blockToEHPreds = new (getAllocator()) BlockToFlowListMap(getAllocator());
          }
          return m_blockToEHPreds;
      }
  
      void* ehEmitCookie(BasicBlock* block);
      UNATIVE_OFFSET ehCodeOffset(BasicBlock* block);
  
      EHblkDsc* ehInitHndRange(BasicBlock* src, IL_OFFSET* hndBeg, IL_OFFSET* hndEnd, bool* inFilter);
  
      EHblkDsc* ehInitTryRange(BasicBlock* src, IL_OFFSET* tryBeg, IL_OFFSET* tryEnd);
  
      EHblkDsc* ehInitHndBlockRange(BasicBlock* blk, BasicBlock** hndBeg, BasicBlock** hndLast, bool* inFilter);
  
      EHblkDsc* ehInitTryBlockRange(BasicBlock* blk, BasicBlock** tryBeg, BasicBlock** tryLast);
  
      void fgSetTryBeg(EHblkDsc* handlerTab, BasicBlock* newTryBeg);
  
      void fgSetTryEnd(EHblkDsc* handlerTab, BasicBlock* newTryLast);
  
      void fgSetHndEnd(EHblkDsc* handlerTab, BasicBlock* newHndLast);
  
      void fgSkipRmvdBlocks(EHblkDsc* handlerTab);
  
      void fgAllocEHTable();
  
      void fgRemoveEHTableEntry(unsigned XTnum);
  
  #if defined(FEATURE_EH_FUNCLETS)
  
      EHblkDsc* fgAddEHTableEntry(unsigned XTnum);
  
  #endif // FEATURE_EH_FUNCLETS
  
  #if !FEATURE_EH
      void fgRemoveEH();
  #endif // !FEATURE_EH
  
      void fgSortEHTable();
  
      // Causes the EH table to obey some well-formedness conditions, by inserting
      // empty BB's when necessary:
      //   * No block is both the first block of a handler and the first block of a try.
      //   * No block is the first block of multiple 'try' regions.
      //   * No block is the last block of multiple EH regions.
      void fgNormalizeEH();
      bool fgNormalizeEHCase1();
      bool fgNormalizeEHCase2();
      bool fgNormalizeEHCase3();
  
      void fgCheckForLoopsInHandlers();
  
  #ifdef DEBUG
      void dispIncomingEHClause(unsigned num, const CORINFO_EH_CLAUSE& clause);
      void dispOutgoingEHClause(unsigned num, const CORINFO_EH_CLAUSE& clause);
      void fgVerifyHandlerTab();
      void fgDispHandlerTab();
  #endif // DEBUG
  
      bool fgNeedToSortEHTable;
  
      void verInitEHTree(unsigned numEHClauses);
      void verInsertEhNode(CORINFO_EH_CLAUSE* clause, EHblkDsc* handlerTab);
      void verInsertEhNodeInTree(EHNodeDsc** ppRoot, EHNodeDsc* node);
      void verInsertEhNodeParent(EHNodeDsc** ppRoot, EHNodeDsc* node);
      void verCheckNestingLevel(EHNodeDsc* initRoot);
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                        GenTree and BasicBlock                             XX
      XX                                                                           XX
      XX  Functions to allocate and display the GenTrees and BasicBlocks           XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
      // Functions to create nodes
      Statement* gtNewStmt(GenTree* expr = nullptr);
      Statement* gtNewStmt(GenTree* expr, const DebugInfo& di);
  
      // For unary opers.
      GenTree* gtNewOperNode(genTreeOps oper, var_types type, GenTree* op1, bool doSimplifications = TRUE);
  
      // For binary opers.
      GenTree* gtNewOperNode(genTreeOps oper, var_types type, GenTree* op1, GenTree* op2);
  
      GenTreeQmark* gtNewQmarkNode(var_types type, GenTree* cond, GenTreeColon* colon);
  
      GenTree* gtNewLargeOperNode(genTreeOps oper,
                                  var_types  type = TYP_I_IMPL,
                                  GenTree*   op1  = nullptr,
                                  GenTree*   op2  = nullptr);
  
      GenTreeIntCon* gtNewIconNode(ssize_t value, var_types type = TYP_INT);
      GenTreeIntCon* gtNewIconNode(unsigned fieldOffset, FieldSeqNode* fieldSeq);
  
      GenTree* gtNewPhysRegNode(regNumber reg, var_types type);
  
      GenTree* gtNewJmpTableNode();
  
      GenTree* gtNewIndOfIconHandleNode(var_types indType, size_t value, GenTreeFlags iconFlags, bool isInvariant);
  
      GenTree* gtNewIconHandleNode(size_t value, GenTreeFlags flags, FieldSeqNode* fields = nullptr);
  
      GenTreeFlags gtTokenToIconFlags(unsigned token);
  
      GenTree* gtNewIconEmbHndNode(void* value, void* pValue, GenTreeFlags flags, void* compileTimeHandle);
  
      GenTree* gtNewIconEmbScpHndNode(CORINFO_MODULE_HANDLE scpHnd);
      GenTree* gtNewIconEmbClsHndNode(CORINFO_CLASS_HANDLE clsHnd);
      GenTree* gtNewIconEmbMethHndNode(CORINFO_METHOD_HANDLE methHnd);
      GenTree* gtNewIconEmbFldHndNode(CORINFO_FIELD_HANDLE fldHnd);
  
      GenTree* gtNewStringLiteralNode(InfoAccessType iat, void* pValue);
      GenTreeIntCon* gtNewStringLiteralLength(GenTreeStrCon* node);
  
      GenTree* gtNewLconNode(__int64 value);
  
      GenTree* gtNewDconNode(double value, var_types type = TYP_DOUBLE);
  
      GenTree* gtNewSconNode(int CPX, CORINFO_MODULE_HANDLE scpHandle);
  
      GenTree* gtNewZeroConNode(var_types type);
  
      GenTree* gtNewOneConNode(var_types type);
  
      GenTreeLclVar* gtNewStoreLclVar(unsigned dstLclNum, GenTree* src);
  
  #ifdef FEATURE_SIMD
      GenTree* gtNewSIMDVectorZero(var_types simdType, CorInfoType simdBaseJitType, unsigned simdSize);
  #endif
  
      GenTree* gtNewBlkOpNode(GenTree* dst, GenTree* srcOrFillVal, bool isVolatile, bool isCopyBlock);
  
      GenTree* gtNewPutArgReg(var_types type, GenTree* arg, regNumber argReg);
  
      GenTree* gtNewBitCastNode(var_types type, GenTree* arg);
  
  protected:
      void gtBlockOpInit(GenTree* result, GenTree* dst, GenTree* srcOrFillVal, bool isVolatile);
  
  public:
      GenTreeObj* gtNewObjNode(CORINFO_CLASS_HANDLE structHnd, GenTree* addr);
      void gtSetObjGcInfo(GenTreeObj* objNode);
      GenTree* gtNewStructVal(CORINFO_CLASS_HANDLE structHnd, GenTree* addr);
      GenTree* gtNewBlockVal(GenTree* addr, unsigned size);
  
      GenTree* gtNewCpObjNode(GenTree* dst, GenTree* src, CORINFO_CLASS_HANDLE structHnd, bool isVolatile);
  
      GenTreeCall::Use* gtNewCallArgs(GenTree* node);
      GenTreeCall::Use* gtNewCallArgs(GenTree* node1, GenTree* node2);
      GenTreeCall::Use* gtNewCallArgs(GenTree* node1, GenTree* node2, GenTree* node3);
      GenTreeCall::Use* gtNewCallArgs(GenTree* node1, GenTree* node2, GenTree* node3, GenTree* node4);
      GenTreeCall::Use* gtPrependNewCallArg(GenTree* node, GenTreeCall::Use* args);
      GenTreeCall::Use* gtInsertNewCallArgAfter(GenTree* node, GenTreeCall::Use* after);
  
      GenTreeCall* gtNewCallNode(gtCallTypes           callType,
                                 CORINFO_METHOD_HANDLE handle,
                                 var_types             type,
                                 GenTreeCall::Use*     args,
                                 const DebugInfo&      di = DebugInfo());
  
      GenTreeCall* gtNewIndCallNode(GenTree*          addr,
                                    var_types         type,
                                    GenTreeCall::Use* args,
                                    const DebugInfo&  di = DebugInfo());
  
      GenTreeCall* gtNewHelperCallNode(unsigned helper, var_types type, GenTreeCall::Use* args = nullptr);
  
      GenTreeCall* gtNewRuntimeLookupHelperCallNode(CORINFO_RUNTIME_LOOKUP* pRuntimeLookup,
                                                    GenTree*                ctxTree,
                                                    void*                   compileTimeHandle);
  
      GenTreeLclVar* gtNewLclvNode(unsigned lnum, var_types type DEBUGARG(IL_OFFSET offs = BAD_IL_OFFSET));
      GenTreeLclVar* gtNewLclLNode(unsigned lnum, var_types type DEBUGARG(IL_OFFSET offs = BAD_IL_OFFSET));
  
      GenTreeLclVar* gtNewLclVarAddrNode(unsigned lclNum, var_types type = TYP_I_IMPL);
      GenTreeLclFld* gtNewLclFldAddrNode(unsigned      lclNum,
                                         unsigned      lclOffs,
                                         FieldSeqNode* fieldSeq,
                                         var_types     type = TYP_I_IMPL);
  
  #ifdef FEATURE_SIMD
      GenTreeSIMD* gtNewSIMDNode(
          var_types type, GenTree* op1, SIMDIntrinsicID simdIntrinsicID, CorInfoType simdBaseJitType, unsigned simdSize);
      GenTreeSIMD* gtNewSIMDNode(var_types       type,
                                 GenTree*        op1,
                                 GenTree*        op2,
                                 SIMDIntrinsicID simdIntrinsicID,
                                 CorInfoType     simdBaseJitType,
                                 unsigned        simdSize);
      void SetOpLclRelatedToSIMDIntrinsic(GenTree* op);
  #endif
  
  #ifdef FEATURE_HW_INTRINSICS
      GenTreeHWIntrinsic* gtNewSimdHWIntrinsicNode(var_types      type,
                                                   NamedIntrinsic hwIntrinsicID,
                                                   CorInfoType    simdBaseJitType,
                                                   unsigned       simdSize,
                                                   bool           isSimdAsHWIntrinsic = false);
      GenTreeHWIntrinsic* gtNewSimdHWIntrinsicNode(var_types      type,
                                                   GenTree*       op1,
                                                   NamedIntrinsic hwIntrinsicID,
                                                   CorInfoType    simdBaseJitType,
                                                   unsigned       simdSize,
                                                   bool           isSimdAsHWIntrinsic = false);
      GenTreeHWIntrinsic* gtNewSimdHWIntrinsicNode(var_types      type,
                                                   GenTree*       op1,
                                                   GenTree*       op2,
                                                   NamedIntrinsic hwIntrinsicID,
                                                   CorInfoType    simdBaseJitType,
                                                   unsigned       simdSize,
                                                   bool           isSimdAsHWIntrinsic = false);
      GenTreeHWIntrinsic* gtNewSimdHWIntrinsicNode(var_types      type,
                                                   GenTree*       op1,
                                                   GenTree*       op2,
                                                   GenTree*       op3,
                                                   NamedIntrinsic hwIntrinsicID,
                                                   CorInfoType    simdBaseJitType,
                                                   unsigned       simdSize,
                                                   bool           isSimdAsHWIntrinsic = false);
      GenTreeHWIntrinsic* gtNewSimdHWIntrinsicNode(var_types      type,
                                                   GenTree*       op1,
                                                   GenTree*       op2,
                                                   GenTree*       op3,
                                                   GenTree*       op4,
                                                   NamedIntrinsic hwIntrinsicID,
                                                   CorInfoType    simdBaseJitType,
                                                   unsigned       simdSize,
                                                   bool           isSimdAsHWIntrinsic = false);
      GenTreeHWIntrinsic* gtNewSimdHWIntrinsicNode(var_types      type,
                                                   GenTree**      operands,
                                                   size_t         operandCount,
                                                   NamedIntrinsic hwIntrinsicID,
                                                   CorInfoType    simdBaseJitType,
                                                   unsigned       simdSize,
                                                   bool           isSimdAsHWIntrinsic = false);
      GenTreeHWIntrinsic* gtNewSimdHWIntrinsicNode(var_types              type,
                                                   IntrinsicNodeBuilder&& nodeBuilder,
                                                   NamedIntrinsic         hwIntrinsicID,
                                                   CorInfoType            simdBaseJitType,
                                                   unsigned               simdSize,
                                                   bool                   isSimdAsHWIntrinsic = false);
  
      GenTreeHWIntrinsic* gtNewSimdAsHWIntrinsicNode(var_types      type,
                                                     NamedIntrinsic hwIntrinsicID,
                                                     CorInfoType    simdBaseJitType,
                                                     unsigned       simdSize)
      {
          bool isSimdAsHWIntrinsic = true;
          return gtNewSimdHWIntrinsicNode(type, hwIntrinsicID, simdBaseJitType, simdSize, isSimdAsHWIntrinsic);
      }
  
      GenTreeHWIntrinsic* gtNewSimdAsHWIntrinsicNode(
          var_types type, GenTree* op1, NamedIntrinsic hwIntrinsicID, CorInfoType simdBaseJitType, unsigned simdSize)
      {
          bool isSimdAsHWIntrinsic = true;
          return gtNewSimdHWIntrinsicNode(type, op1, hwIntrinsicID, simdBaseJitType, simdSize, isSimdAsHWIntrinsic);
      }
  
      GenTreeHWIntrinsic* gtNewSimdAsHWIntrinsicNode(var_types      type,
                                                     GenTree*       op1,
                                                     GenTree*       op2,
                                                     NamedIntrinsic hwIntrinsicID,
                                                     CorInfoType    simdBaseJitType,
                                                     unsigned       simdSize)
      {
          bool isSimdAsHWIntrinsic = true;
          return gtNewSimdHWIntrinsicNode(type, op1, op2, hwIntrinsicID, simdBaseJitType, simdSize, isSimdAsHWIntrinsic);
      }
  
      GenTreeHWIntrinsic* gtNewSimdAsHWIntrinsicNode(var_types      type,
                                                     GenTree*       op1,
                                                     GenTree*       op2,
                                                     GenTree*       op3,
                                                     NamedIntrinsic hwIntrinsicID,
                                                     CorInfoType    simdBaseJitType,
                                                     unsigned       simdSize)
      {
          bool isSimdAsHWIntrinsic = true;
          return gtNewSimdHWIntrinsicNode(type, op1, op2, op3, hwIntrinsicID, simdBaseJitType, simdSize,
                                          isSimdAsHWIntrinsic);
      }
  
      GenTree* gtNewSimdAbsNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdBinOpNode(genTreeOps  op,
                                  var_types   type,
                                  GenTree*    op1,
                                  GenTree*    op2,
                                  CorInfoType simdBaseJitType,
                                  unsigned    simdSize,
                                  bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdCeilNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdCmpOpNode(genTreeOps  op,
                                  var_types   type,
                                  GenTree*    op1,
                                  GenTree*    op2,
                                  CorInfoType simdBaseJitType,
                                  unsigned    simdSize,
                                  bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdCmpOpAllNode(genTreeOps  op,
                                     var_types   type,
                                     GenTree*    op1,
                                     GenTree*    op2,
                                     CorInfoType simdBaseJitType,
                                     unsigned    simdSize,
                                     bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdCmpOpAnyNode(genTreeOps  op,
                                     var_types   type,
                                     GenTree*    op1,
                                     GenTree*    op2,
                                     CorInfoType simdBaseJitType,
                                     unsigned    simdSize,
                                     bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdCndSelNode(var_types   type,
                                   GenTree*    op1,
                                   GenTree*    op2,
                                   GenTree*    op3,
                                   CorInfoType simdBaseJitType,
                                   unsigned    simdSize,
                                   bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdCreateBroadcastNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdDotProdNode(var_types   type,
                                    GenTree*    op1,
                                    GenTree*    op2,
                                    CorInfoType simdBaseJitType,
                                    unsigned    simdSize,
                                    bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdFloorNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdGetElementNode(var_types   type,
                                       GenTree*    op1,
                                       GenTree*    op2,
                                       CorInfoType simdBaseJitType,
                                       unsigned    simdSize,
                                       bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdMaxNode(var_types   type,
                                GenTree*    op1,
                                GenTree*    op2,
                                CorInfoType simdBaseJitType,
                                unsigned    simdSize,
                                bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdMinNode(var_types   type,
                                GenTree*    op1,
                                GenTree*    op2,
                                CorInfoType simdBaseJitType,
                                unsigned    simdSize,
                                bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdNarrowNode(var_types   type,
                                   GenTree*    op1,
                                   GenTree*    op2,
                                   CorInfoType simdBaseJitType,
                                   unsigned    simdSize,
                                   bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdSqrtNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdSumNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdUnOpNode(genTreeOps  op,
                                 var_types   type,
                                 GenTree*    op1,
                                 CorInfoType simdBaseJitType,
                                 unsigned    simdSize,
                                 bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdWidenLowerNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdWidenUpperNode(
          var_types type, GenTree* op1, CorInfoType simdBaseJitType, unsigned simdSize, bool isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdWithElementNode(var_types   type,
                                        GenTree*    op1,
                                        GenTree*    op2,
                                        GenTree*    op3,
                                        CorInfoType simdBaseJitType,
                                        unsigned    simdSize,
                                        bool        isSimdAsHWIntrinsic);
  
      GenTree* gtNewSimdZeroNode(var_types   type,
                                 CorInfoType simdBaseJitType,
                                 unsigned    simdSize,
                                 bool        isSimdAsHWIntrinsic);
  
      GenTreeHWIntrinsic* gtNewScalarHWIntrinsicNode(var_types type, NamedIntrinsic hwIntrinsicID);
      GenTreeHWIntrinsic* gtNewScalarHWIntrinsicNode(var_types type, GenTree* op1, NamedIntrinsic hwIntrinsicID);
      GenTreeHWIntrinsic* gtNewScalarHWIntrinsicNode(var_types      type,
                                                     GenTree*       op1,
                                                     GenTree*       op2,
                                                     NamedIntrinsic hwIntrinsicID);
      GenTreeHWIntrinsic* gtNewScalarHWIntrinsicNode(
          var_types type, GenTree* op1, GenTree* op2, GenTree* op3, NamedIntrinsic hwIntrinsicID);
      CORINFO_CLASS_HANDLE gtGetStructHandleForHWSIMD(var_types simdType, CorInfoType simdBaseJitType);
      CorInfoType getBaseJitTypeFromArgIfNeeded(NamedIntrinsic       intrinsic,
                                                CORINFO_CLASS_HANDLE clsHnd,
                                                CORINFO_SIG_INFO*    sig,
                                                CorInfoType          simdBaseJitType);
  #endif // FEATURE_HW_INTRINSICS
  
      GenTree* gtNewMustThrowException(unsigned helper, var_types type, CORINFO_CLASS_HANDLE clsHnd);
  
      GenTreeLclFld* gtNewLclFldNode(unsigned lnum, var_types type, unsigned offset);
      GenTree* gtNewInlineCandidateReturnExpr(GenTree* inlineCandidate, var_types type, BasicBlockFlags bbFlags);
  
      GenTree* gtNewFieldRef(var_types type, CORINFO_FIELD_HANDLE fldHnd, GenTree* obj = nullptr, DWORD offset = 0);
  
      GenTree* gtNewIndexRef(var_types typ, GenTree* arrayOp, GenTree* indexOp);
  
      GenTreeArrLen* gtNewArrLen(var_types typ, GenTree* arrayOp, int lenOffset, BasicBlock* block);
  
      GenTreeIndir* gtNewIndir(var_types typ, GenTree* addr);
  
      GenTree* gtNewNullCheck(GenTree* addr, BasicBlock* basicBlock);
  
      var_types gtTypeForNullCheck(GenTree* tree);
      void gtChangeOperToNullCheck(GenTree* tree, BasicBlock* block);
  
      static fgArgTabEntry* gtArgEntryByArgNum(GenTreeCall* call, unsigned argNum);
      static fgArgTabEntry* gtArgEntryByNode(GenTreeCall* call, GenTree* node);
      fgArgTabEntry* gtArgEntryByLateArgIndex(GenTreeCall* call, unsigned lateArgInx);
      static GenTree* gtArgNodeByLateArgInx(GenTreeCall* call, unsigned lateArgInx);
  
      GenTreeOp* gtNewAssignNode(GenTree* dst, GenTree* src);
  
      GenTree* gtNewTempAssign(unsigned         tmp,
                               GenTree*         val,
                               Statement**      pAfterStmt = nullptr,
                               const DebugInfo& di         = DebugInfo(),
                               BasicBlock*      block      = nullptr);
  
      GenTree* gtNewRefCOMfield(GenTree*                objPtr,
                                CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                CORINFO_ACCESS_FLAGS    access,
                                CORINFO_FIELD_INFO*     pFieldInfo,
                                var_types               lclTyp,
                                CORINFO_CLASS_HANDLE    structType,
                                GenTree*                assg);
  
      GenTree* gtNewNothingNode();
  
      GenTree* gtNewArgPlaceHolderNode(var_types type, CORINFO_CLASS_HANDLE clsHnd);
  
      GenTree* gtUnusedValNode(GenTree* expr);
  
      GenTree* gtNewKeepAliveNode(GenTree* op);
  
      GenTreeCast* gtNewCastNode(var_types typ, GenTree* op1, bool fromUnsigned, var_types castType);
  
      GenTreeCast* gtNewCastNodeL(var_types typ, GenTree* op1, bool fromUnsigned, var_types castType);
  
      GenTreeAllocObj* gtNewAllocObjNode(
          unsigned int helper, bool helperHasSideEffects, CORINFO_CLASS_HANDLE clsHnd, var_types type, GenTree* op1);
  
      GenTreeAllocObj* gtNewAllocObjNode(CORINFO_RESOLVED_TOKEN* pResolvedToken, bool useParent);
  
      GenTree* gtNewRuntimeLookup(CORINFO_GENERIC_HANDLE hnd, CorInfoGenericHandleType hndTyp, GenTree* lookupTree);
  
      GenTreeIndir* gtNewMethodTableLookup(GenTree* obj);
  
      //------------------------------------------------------------------------
      // Other GenTree functions
  
      GenTree* gtClone(GenTree* tree, bool complexOK = false);
  
      // If `tree` is a lclVar with lclNum `varNum`, return an IntCns with value `varVal`; otherwise,
      // create a copy of `tree`, adding specified flags, replacing uses of lclVar `deepVarNum` with
      // IntCnses with value `deepVarVal`.
      GenTree* gtCloneExpr(
          GenTree* tree, GenTreeFlags addFlags, unsigned varNum, int varVal, unsigned deepVarNum, int deepVarVal);
  
      // Create a copy of `tree`, optionally adding specifed flags, and optionally mapping uses of local
      // `varNum` to int constants with value `varVal`.
      GenTree* gtCloneExpr(GenTree*     tree,
                           GenTreeFlags addFlags = GTF_EMPTY,
                           unsigned     varNum   = BAD_VAR_NUM,
                           int          varVal   = 0)
      {
          return gtCloneExpr(tree, addFlags, varNum, varVal, varNum, varVal);
      }
  
      Statement* gtCloneStmt(Statement* stmt)
      {
          GenTree* exprClone = gtCloneExpr(stmt->GetRootNode());
          return gtNewStmt(exprClone, stmt->GetDebugInfo());
      }
  
      // Internal helper for cloning a call
      GenTreeCall* gtCloneExprCallHelper(GenTreeCall* call,
                                         GenTreeFlags addFlags   = GTF_EMPTY,
                                         unsigned     deepVarNum = BAD_VAR_NUM,
                                         int          deepVarVal = 0);
  
      // Create copy of an inline or guarded devirtualization candidate tree.
      GenTreeCall* gtCloneCandidateCall(GenTreeCall* call);
  
      void gtUpdateSideEffects(Statement* stmt, GenTree* tree);
  
      void gtUpdateTreeAncestorsSideEffects(GenTree* tree);
  
      void gtUpdateStmtSideEffects(Statement* stmt);
  
      void gtUpdateNodeSideEffects(GenTree* tree);
  
      void gtUpdateNodeOperSideEffects(GenTree* tree);
  
      void gtUpdateNodeOperSideEffectsPost(GenTree* tree);
  
      // Returns "true" iff the complexity (not formally defined, but first interpretation
      // is #of nodes in subtree) of "tree" is greater than "limit".
      // (This is somewhat redundant with the "GetCostEx()/GetCostSz()" fields, but can be used
      // before they have been set.)
      bool gtComplexityExceeds(GenTree** tree, unsigned limit);
  
      GenTree* gtReverseCond(GenTree* tree);
  
      static bool gtHasRef(GenTree* tree, ssize_t lclNum);
  
      bool gtHasLocalsWithAddrOp(GenTree* tree);
  
      unsigned gtSetCallArgsOrder(const GenTreeCall::UseList& args, bool lateArgs, int* callCostEx, int* callCostSz);
      unsigned gtSetMultiOpOrder(GenTreeMultiOp* multiOp);
  
      void gtWalkOp(GenTree** op1, GenTree** op2, GenTree* base, bool constOnly);
  
  #ifdef DEBUG
      unsigned gtHashValue(GenTree* tree);
  
      GenTree* gtWalkOpEffectiveVal(GenTree* op);
  #endif
  
      void gtPrepareCost(GenTree* tree);
      bool gtIsLikelyRegVar(GenTree* tree);
  
      // Returns true iff the secondNode can be swapped with firstNode.
      bool gtCanSwapOrder(GenTree* firstNode, GenTree* secondNode);
  
      // Given an address expression, compute its costs and addressing mode opportunities,
      // and mark addressing mode candidates as GTF_DONT_CSE.
      // TODO-Throughput - Consider actually instantiating these early, to avoid
      // having to re-run the algorithm that looks for them (might also improve CQ).
      bool gtMarkAddrMode(GenTree* addr, int* costEx, int* costSz, var_types type);
  
      unsigned gtSetEvalOrder(GenTree* tree);
  
      void gtSetStmtInfo(Statement* stmt);
  
      // Returns "true" iff "node" has any of the side effects in "flags".
      bool gtNodeHasSideEffects(GenTree* node, GenTreeFlags flags);
  
      // Returns "true" iff "tree" or its (transitive) children have any of the side effects in "flags".
      bool gtTreeHasSideEffects(GenTree* tree, GenTreeFlags flags);
  
      // Appends 'expr' in front of 'list'
      //    'list' will typically start off as 'nullptr'
      //    when 'list' is non-null a GT_COMMA node is used to insert 'expr'
      GenTree* gtBuildCommaList(GenTree* list, GenTree* expr);
  
      void gtExtractSideEffList(GenTree*     expr,
                                GenTree**    pList,
                                GenTreeFlags GenTreeFlags = GTF_SIDE_EFFECT,
                                bool         ignoreRoot   = false);
  
      GenTree* gtGetThisArg(GenTreeCall* call);
  
      // Static fields of struct types (and sometimes the types that those are reduced to) are represented by having the
      // static field contain an object pointer to the boxed struct.  This simplifies the GC implementation...but
      // complicates the JIT somewhat.  This predicate returns "true" iff a node with type "fieldNodeType", representing
      // the given "fldHnd", is such an object pointer.
      bool gtIsStaticFieldPtrToBoxedStruct(var_types fieldNodeType, CORINFO_FIELD_HANDLE fldHnd);
  
      // Return true if call is a recursive call; return false otherwise.
      // Note when inlining, this looks for calls back to the root method.
      bool gtIsRecursiveCall(GenTreeCall* call)
      {
          return gtIsRecursiveCall(call->gtCallMethHnd);
      }
  
      bool gtIsRecursiveCall(CORINFO_METHOD_HANDLE callMethodHandle)
      {
          return (callMethodHandle == impInlineRoot()->info.compMethodHnd);
      }
  
      //-------------------------------------------------------------------------
  
      GenTree* gtFoldExpr(GenTree* tree);
      GenTree* gtFoldExprConst(GenTree* tree);
      GenTree* gtFoldExprSpecial(GenTree* tree);
      GenTree* gtFoldBoxNullable(GenTree* tree);
      GenTree* gtFoldExprCompare(GenTree* tree);
      GenTree* gtCreateHandleCompare(genTreeOps             oper,
                                     GenTree*               op1,
                                     GenTree*               op2,
                                     CorInfoInlineTypeCheck typeCheckInliningResult);
      GenTree* gtFoldExprCall(GenTreeCall* call);
      GenTree* gtFoldTypeCompare(GenTree* tree);
      GenTree* gtFoldTypeEqualityCall(bool isEq, GenTree* op1, GenTree* op2);
  
      // Options to control behavior of gtTryRemoveBoxUpstreamEffects
      enum BoxRemovalOptions
      {
          BR_REMOVE_AND_NARROW, // remove effects, minimize remaining work, return possibly narrowed source tree
          BR_REMOVE_AND_NARROW_WANT_TYPE_HANDLE, // remove effects and minimize remaining work, return type handle tree
          BR_REMOVE_BUT_NOT_NARROW,              // remove effects, return original source tree
          BR_DONT_REMOVE,                        // check if removal is possible, return copy source tree
          BR_DONT_REMOVE_WANT_TYPE_HANDLE,       // check if removal is possible, return type handle tree
          BR_MAKE_LOCAL_COPY                     // revise box to copy to temp local and return local's address
      };
  
      GenTree* gtTryRemoveBoxUpstreamEffects(GenTree* tree, BoxRemovalOptions options = BR_REMOVE_AND_NARROW);
      GenTree* gtOptimizeEnumHasFlag(GenTree* thisOp, GenTree* flagOp);
  
      //-------------------------------------------------------------------------
      // Get the handle, if any.
      CORINFO_CLASS_HANDLE gtGetStructHandleIfPresent(GenTree* tree);
      // Get the handle, and assert if not found.
      CORINFO_CLASS_HANDLE gtGetStructHandle(GenTree* tree);
      // Get the handle for a ref type.
      CORINFO_CLASS_HANDLE gtGetClassHandle(GenTree* tree, bool* pIsExact, bool* pIsNonNull);
      // Get the class handle for an helper call
      CORINFO_CLASS_HANDLE gtGetHelperCallClassHandle(GenTreeCall* call, bool* pIsExact, bool* pIsNonNull);
      // Get the element handle for an array of ref type.
      CORINFO_CLASS_HANDLE gtGetArrayElementClassHandle(GenTree* array);
      // Get a class handle from a helper call argument
      CORINFO_CLASS_HANDLE gtGetHelperArgClassHandle(GenTree* array);
      // Get the class handle for a field
      CORINFO_CLASS_HANDLE gtGetFieldClassHandle(CORINFO_FIELD_HANDLE fieldHnd, bool* pIsExact, bool* pIsNonNull);
      // Check if this tree is a gc static base helper call
      bool gtIsStaticGCBaseHelperCall(GenTree* tree);
  
  //-------------------------------------------------------------------------
  // Functions to display the trees
  
  #ifdef DEBUG
      void gtDispNode(GenTree* tree, IndentStack* indentStack, _In_z_ const char* msg, bool isLIR);
  
      void gtDispConst(GenTree* tree);
      void gtDispLeaf(GenTree* tree, IndentStack* indentStack);
      void gtDispNodeName(GenTree* tree);
  #if FEATURE_MULTIREG_RET
      unsigned gtDispRegCount(GenTree* tree);
  #endif
      void gtDispRegVal(GenTree* tree);
      void gtDispZeroFieldSeq(GenTree* tree);
      void gtDispVN(GenTree* tree);
      void gtDispCommonEndLine(GenTree* tree);
  
      enum IndentInfo
      {
          IINone,
          IIArc,
          IIArcTop,
          IIArcBottom,
          IIEmbedded,
          IIError,
          IndentInfoCount
      };
      void gtDispChild(GenTree*             child,
                       IndentStack*         indentStack,
                       IndentInfo           arcType,
                       _In_opt_ const char* msg     = nullptr,
                       bool                 topOnly = false);
      void gtDispTree(GenTree*             tree,
                      IndentStack*         indentStack = nullptr,
                      _In_opt_ const char* msg         = nullptr,
                      bool                 topOnly     = false,
                      bool                 isLIR       = false);
      void gtGetLclVarNameInfo(unsigned lclNum, const char** ilKindOut, const char** ilNameOut, unsigned* ilNumOut);
      int gtGetLclVarName(unsigned lclNum, char* buf, unsigned buf_remaining);
      char* gtGetLclVarName(unsigned lclNum);
      void gtDispLclVar(unsigned lclNum, bool padForBiggestDisp = true);
      void gtDispLclVarStructType(unsigned lclNum);
      void gtDispClassLayout(ClassLayout* layout, var_types type);
      void gtDispILLocation(const ILLocation& loc);
      void gtDispStmt(Statement* stmt, const char* msg = nullptr);
      void gtDispBlockStmts(BasicBlock* block);
      void gtGetArgMsg(GenTreeCall* call, GenTree* arg, unsigned argNum, char* bufp, unsigned bufLength);
      void gtGetLateArgMsg(GenTreeCall* call, GenTree* arg, int argNum, char* bufp, unsigned bufLength);
      void gtDispArgList(GenTreeCall* call, GenTree* lastCallOperand, IndentStack* indentStack);
      void gtDispFieldSeq(FieldSeqNode* pfsn);
  
      void gtDispRange(LIR::ReadOnlyRange const& range);
  
      void gtDispTreeRange(LIR::Range& containingRange, GenTree* tree);
  
      void gtDispLIRNode(GenTree* node, const char* prefixMsg = nullptr);
  #endif
  
      // For tree walks
  
      enum fgWalkResult
      {
          WALK_CONTINUE,
          WALK_SKIP_SUBTREES,
          WALK_ABORT
      };
      struct fgWalkData;
      typedef fgWalkResult(fgWalkPreFn)(GenTree** pTree, fgWalkData* data);
      typedef fgWalkResult(fgWalkPostFn)(GenTree** pTree, fgWalkData* data);
  
      static fgWalkPreFn gtMarkColonCond;
      static fgWalkPreFn gtClearColonCond;
  
      struct FindLinkData
      {
          GenTree*  nodeToFind;
          GenTree** result;
          GenTree*  parent;
      };
  
      FindLinkData gtFindLink(Statement* stmt, GenTree* node);
      bool gtHasCatchArg(GenTree* tree);
  
      typedef ArrayStack<GenTree*> GenTreeStack;
  
      static bool gtHasCallOnStack(GenTreeStack* parentStack);
  
  //=========================================================================
  // BasicBlock functions
  #ifdef DEBUG
      // This is a debug flag we will use to assert when creating block during codegen
      // as this interferes with procedure splitting. If you know what you're doing, set
      // it to true before creating the block. (DEBUG only)
      bool fgSafeBasicBlockCreation;
  #endif
  
      BasicBlock* bbNewBasicBlock(BBjumpKinds jumpKind);
      void placeLoopAlignInstructions();
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           LclVarsInfo                                     XX
      XX                                                                           XX
      XX   The variables to be used by the code generator.                         XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
      //
      // For both PROMOTION_TYPE_NONE and PROMOTION_TYPE_DEPENDENT the struct will
      // be placed in the stack frame and it's fields must be laid out sequentially.
      //
      // For PROMOTION_TYPE_INDEPENDENT each of the struct's fields is replaced by
      //  a local variable that can be enregistered or placed in the stack frame.
      //  The fields do not need to be laid out sequentially
      //
      enum lvaPromotionType
      {
          PROMOTION_TYPE_NONE,        // The struct local is not promoted
          PROMOTION_TYPE_INDEPENDENT, // The struct local is promoted,
                                      //   and its field locals are independent of its parent struct local.
          PROMOTION_TYPE_DEPENDENT    // The struct local is promoted,
                                      //   but its field locals depend on its parent struct local.
      };
  
      /*****************************************************************************/
  
      enum FrameLayoutState
      {
          NO_FRAME_LAYOUT,
          INITIAL_FRAME_LAYOUT,
          PRE_REGALLOC_FRAME_LAYOUT,
          REGALLOC_FRAME_LAYOUT,
          TENTATIVE_FRAME_LAYOUT,
          FINAL_FRAME_LAYOUT
      };
  
  public:
      RefCountState lvaRefCountState; // Current local ref count state
  
      bool lvaLocalVarRefCounted() const
      {
          return lvaRefCountState == RCS_NORMAL;
      }
  
      bool     lvaTrackedFixed; // true: We cannot add new 'tracked' variable
      unsigned lvaCount;        // total number of locals, which includes function arguments,
                                // special arguments, IL local variables, and JIT temporary variables
  
      LclVarDsc* lvaTable;    // variable descriptor table
      unsigned   lvaTableCnt; // lvaTable size (>= lvaCount)
  
      unsigned lvaTrackedCount;             // actual # of locals being tracked
      unsigned lvaTrackedCountInSizeTUnits; // min # of size_t's sufficient to hold a bit for all the locals being tracked
  
  #ifdef DEBUG
      VARSET_TP lvaTrackedVars; // set of tracked variables
  #endif
  #ifndef TARGET_64BIT
      VARSET_TP lvaLongVars; // set of long (64-bit) variables
  #endif
      VARSET_TP lvaFloatVars; // set of floating-point (32-bit and 64-bit) variables
  
      unsigned lvaCurEpoch; // VarSets are relative to a specific set of tracked var indices.
                            // It that changes, this changes.  VarSets from different epochs
                            // cannot be meaningfully combined.
  
      unsigned GetCurLVEpoch()
      {
          return lvaCurEpoch;
      }
  
      // reverse map of tracked number to var number
      unsigned  lvaTrackedToVarNumSize;
      unsigned* lvaTrackedToVarNum;
  
  #if DOUBLE_ALIGN
  #ifdef DEBUG
      // # of procs compiled a with double-aligned stack
      static unsigned s_lvaDoubleAlignedProcsCount;
  #endif
  #endif
  
      // Getters and setters for address-exposed and do-not-enregister local var properties.
      bool lvaVarAddrExposed(unsigned varNum) const;
      void lvaSetVarAddrExposed(unsigned varNum DEBUGARG(AddressExposedReason reason));
      void lvaSetVarLiveInOutOfHandler(unsigned varNum);
      bool lvaVarDoNotEnregister(unsigned varNum);
  
      void lvSetMinOptsDoNotEnreg();
  
      bool lvaEnregEHVars;
      bool lvaEnregMultiRegVars;
  
      void lvaSetVarDoNotEnregister(unsigned varNum DEBUGARG(DoNotEnregisterReason reason));
  
      unsigned lvaVarargsHandleArg;
  #ifdef TARGET_X86
      unsigned lvaVarargsBaseOfStkArgs; // Pointer (computed based on incoming varargs handle) to the start of the stack
                                        // arguments
  #endif                                // TARGET_X86
  
      unsigned lvaInlinedPInvokeFrameVar; // variable representing the InlinedCallFrame
      unsigned lvaReversePInvokeFrameVar; // variable representing the reverse PInvoke frame
  #if FEATURE_FIXED_OUT_ARGS
      unsigned lvaPInvokeFrameRegSaveVar; // variable representing the RegSave for PInvoke inlining.
  #endif
      unsigned lvaMonAcquired; // boolean variable introduced into in synchronized methods
                               // that tracks whether the lock has been taken
  
      unsigned lvaArg0Var; // The lclNum of arg0. Normally this will be info.compThisArg.
                           // However, if there is a "ldarga 0" or "starg 0" in the IL,
                           // we will redirect all "ldarg(a) 0" and "starg 0" to this temp.
  
      unsigned lvaInlineeReturnSpillTemp; // The temp to spill the non-VOID return expression
                                          // in case there are multiple BBJ_RETURN blocks in the inlinee
                                          // or if the inlinee has GC ref locals.
  
  #if FEATURE_FIXED_OUT_ARGS
      unsigned            lvaOutgoingArgSpaceVar;  // dummy TYP_LCLBLK var for fixed outgoing argument space
      PhasedVar<unsigned> lvaOutgoingArgSpaceSize; // size of fixed outgoing argument space
  #endif                                           // FEATURE_FIXED_OUT_ARGS
  
      static unsigned GetOutgoingArgByteSize(unsigned sizeWithoutPadding)
      {
          return roundUp(sizeWithoutPadding, TARGET_POINTER_SIZE);
      }
  
      // Variable representing the return address. The helper-based tailcall
      // mechanism passes the address of the return address to a runtime helper
      // where it is used to detect tail-call chains.
      unsigned lvaRetAddrVar;
  
  #if defined(DEBUG) && defined(TARGET_XARCH)
  
      unsigned lvaReturnSpCheck; // Stores SP to confirm it is not corrupted on return.
  
  #endif // defined(DEBUG) && defined(TARGET_XARCH)
  
  #if defined(DEBUG) && defined(TARGET_X86)
  
      unsigned lvaCallSpCheck; // Stores SP to confirm it is not corrupted after every call.
  
  #endif // defined(DEBUG) && defined(TARGET_X86)
  
      bool lvaGenericsContextInUse;
  
      bool lvaKeepAliveAndReportThis(); // Synchronized instance method of a reference type, or
                                        // CORINFO_GENERICS_CTXT_FROM_THIS?
      bool lvaReportParamTypeArg();     // Exceptions and CORINFO_GENERICS_CTXT_FROM_PARAMTYPEARG?
  
  //-------------------------------------------------------------------------
  // All these frame offsets are inter-related and must be kept in sync
  
  #if !defined(FEATURE_EH_FUNCLETS)
      // This is used for the callable handlers
      unsigned lvaShadowSPslotsVar; // TYP_BLK variable for all the shadow SP slots
  #endif                            // FEATURE_EH_FUNCLETS
  
      int lvaCachedGenericContextArgOffs;
      int lvaCachedGenericContextArgOffset(); // For CORINFO_CALLCONV_PARAMTYPE and if generic context is passed as
                                              // THIS pointer
  
  #ifdef JIT32_GCENCODER
  
      unsigned lvaLocAllocSPvar; // variable which stores the value of ESP after the the last alloca/localloc
  
  #endif // JIT32_GCENCODER
  
      unsigned lvaNewObjArrayArgs; // variable with arguments for new MD array helper
  
      // TODO-Review: Prior to reg predict we reserve 24 bytes for Spill temps.
      //              after the reg predict we will use a computed maxTmpSize
      //              which is based upon the number of spill temps predicted by reg predict
      //              All this is necessary because if we under-estimate the size of the spill
      //              temps we could fail when encoding instructions that reference stack offsets for ARM.
      //
      // Pre codegen max spill temp size.
      static const unsigned MAX_SPILL_TEMP_SIZE = 24;
  
      //-------------------------------------------------------------------------
  
      unsigned lvaGetMaxSpillTempSize();
  #ifdef TARGET_ARM
      bool lvaIsPreSpilled(unsigned lclNum, regMaskTP preSpillMask);
  #endif // TARGET_ARM
      void lvaAssignFrameOffsets(FrameLayoutState curState);
      void lvaFixVirtualFrameOffsets();
      void lvaUpdateArgWithInitialReg(LclVarDsc* varDsc);
      void lvaUpdateArgsWithInitialReg();
      void lvaAssignVirtualFrameOffsetsToArgs();
  #ifdef UNIX_AMD64_ABI
      int lvaAssignVirtualFrameOffsetToArg(unsigned lclNum, unsigned argSize, int argOffs, int* callerArgOffset);
  #else  // !UNIX_AMD64_ABI
      int lvaAssignVirtualFrameOffsetToArg(unsigned lclNum, unsigned argSize, int argOffs);
  #endif // !UNIX_AMD64_ABI
      void lvaAssignVirtualFrameOffsetsToLocals();
      int lvaAllocLocalAndSetVirtualOffset(unsigned lclNum, unsigned size, int stkOffs);
  #ifdef TARGET_AMD64
      // Returns true if compCalleeRegsPushed (including RBP if used as frame pointer) is even.
      bool lvaIsCalleeSavedIntRegCountEven();
  #endif
      void lvaAlignFrame();
      void lvaAssignFrameOffsetsToPromotedStructs();
      int lvaAllocateTemps(int stkOffs, bool mustDoubleAlign);
  
  #ifdef DEBUG
      void lvaDumpRegLocation(unsigned lclNum);
      void lvaDumpFrameLocation(unsigned lclNum);
      void lvaDumpEntry(unsigned lclNum, FrameLayoutState curState, size_t refCntWtdWidth = 6);
      void lvaTableDump(FrameLayoutState curState = NO_FRAME_LAYOUT); // NO_FRAME_LAYOUT means use the current frame
                                                                      // layout state defined by lvaDoneFrameLayout
  #endif
  
  // Limit frames size to 1GB. The maximum is 2GB in theory - make it intentionally smaller
  // to avoid bugs from borderline cases.
  #define MAX_FrameSize 0x3FFFFFFF
      void lvaIncrementFrameSize(unsigned size);
  
      unsigned lvaFrameSize(FrameLayoutState curState);
  
      // Returns the caller-SP-relative offset for the SP/FP relative offset determined by FP based.
      int lvaToCallerSPRelativeOffset(int offs, bool isFpBased, bool forRootFrame = true) const;
  
      // Returns the caller-SP-relative offset for the local variable "varNum."
      int lvaGetCallerSPRelativeOffset(unsigned varNum);
  
      // Returns the SP-relative offset for the local variable "varNum". Illegal to ask this for functions with localloc.
      int lvaGetSPRelativeOffset(unsigned varNum);
  
      int lvaToInitialSPRelativeOffset(unsigned offset, bool isFpBased);
      int lvaGetInitialSPRelativeOffset(unsigned varNum);
  
      // True if this is an OSR compilation and this local is potentially
      // located on the original method stack frame.
      bool lvaIsOSRLocal(unsigned varNum);
  
      //------------------------ For splitting types ----------------------------
  
      void lvaInitTypeRef();
  
      void lvaInitArgs(InitVarDscInfo* varDscInfo);
      void lvaInitThisPtr(InitVarDscInfo* varDscInfo);
      void lvaInitRetBuffArg(InitVarDscInfo* varDscInfo, bool useFixedRetBufReg);
      void lvaInitUserArgs(InitVarDscInfo* varDscInfo, unsigned skipArgs, unsigned takeArgs);
      void lvaInitGenericsCtxt(InitVarDscInfo* varDscInfo);
      void lvaInitVarArgsHandle(InitVarDscInfo* varDscInfo);
  
      void lvaInitVarDsc(LclVarDsc*              varDsc,
                         unsigned                varNum,
                         CorInfoType             corInfoType,
                         CORINFO_CLASS_HANDLE    typeHnd,
                         CORINFO_ARG_LIST_HANDLE varList,
                         CORINFO_SIG_INFO*       varSig);
  
      static unsigned lvaTypeRefMask(var_types type);
  
      var_types lvaGetActualType(unsigned lclNum);
      var_types lvaGetRealType(unsigned lclNum);
  
      //-------------------------------------------------------------------------
  
      void lvaInit();
  
      LclVarDsc* lvaGetDesc(unsigned lclNum)
      {
          assert(lclNum < lvaCount);
          return &lvaTable[lclNum];
      }
  
      LclVarDsc* lvaGetDesc(unsigned lclNum) const
      {
          assert(lclNum < lvaCount);
          return &lvaTable[lclNum];
      }
  
      LclVarDsc* lvaGetDesc(const GenTreeLclVarCommon* lclVar)
      {
          return lvaGetDesc(lclVar->GetLclNum());
      }
  
      unsigned lvaTrackedIndexToLclNum(unsigned trackedIndex)
      {
          assert(trackedIndex < lvaTrackedCount);
          unsigned lclNum = lvaTrackedToVarNum[trackedIndex];
          assert(lclNum < lvaCount);
          return lclNum;
      }
  
      LclVarDsc* lvaGetDescByTrackedIndex(unsigned trackedIndex)
      {
          return lvaGetDesc(lvaTrackedIndexToLclNum(trackedIndex));
      }
  
      unsigned lvaGetLclNum(const LclVarDsc* varDsc)
      {
          assert((lvaTable <= varDsc) && (varDsc < lvaTable + lvaCount)); // varDsc must point within the table
          assert(((char*)varDsc - (char*)lvaTable) % sizeof(LclVarDsc) ==
                 0); // varDsc better not point in the middle of a variable
          unsigned varNum = (unsigned)(varDsc - lvaTable);
          assert(varDsc == &lvaTable[varNum]);
          return varNum;
      }
  
      unsigned lvaLclSize(unsigned varNum);
      unsigned lvaLclExactSize(unsigned varNum);
  
      bool lvaHaveManyLocals() const;
  
      unsigned lvaGrabTemp(bool shortLifetime DEBUGARG(const char* reason));
      unsigned lvaGrabTemps(unsigned cnt DEBUGARG(const char* reason));
      unsigned lvaGrabTempWithImplicitUse(bool shortLifetime DEBUGARG(const char* reason));
  
      void lvaSortByRefCount();
  
      void lvaMarkLocalVars(); // Local variable ref-counting
      void lvaComputeRefCounts(bool isRecompute, bool setSlotNumbers);
      void lvaMarkLocalVars(BasicBlock* block, bool isRecompute);
  
      void lvaAllocOutgoingArgSpaceVar(); // Set up lvaOutgoingArgSpaceVar
  
      VARSET_VALRET_TP lvaStmtLclMask(Statement* stmt);
  
  #ifdef DEBUG
      struct lvaStressLclFldArgs
      {
          Compiler* m_pCompiler;
          bool      m_bFirstPass;
      };
  
      static fgWalkPreFn lvaStressLclFldCB;
      void               lvaStressLclFld();
  
      void lvaDispVarSet(VARSET_VALARG_TP set, VARSET_VALARG_TP allVars);
      void lvaDispVarSet(VARSET_VALARG_TP set);
  
  #endif
  
  #ifdef TARGET_ARM
      int lvaFrameAddress(int varNum, bool mustBeFPBased, regNumber* pBaseReg, int addrModeOffset, bool isFloatUsage);
  #else
      int lvaFrameAddress(int varNum, bool* pFPbased);
  #endif
  
      bool lvaIsParameter(unsigned varNum);
      bool lvaIsRegArgument(unsigned varNum);
      bool lvaIsOriginalThisArg(unsigned varNum); // Is this varNum the original this argument?
      bool lvaIsOriginalThisReadOnly();           // return true if there is no place in the code
                                                  // that writes to arg0
  
      // For x64 this is 3, 5, 6, 7, >8 byte structs that are passed by reference.
      // For ARM64, this is structs larger than 16 bytes that are passed by reference.
      bool lvaIsImplicitByRefLocal(unsigned varNum)
      {
  #if defined(TARGET_AMD64) || defined(TARGET_ARM64)
          LclVarDsc* varDsc = lvaGetDesc(varNum);
          if (varDsc->lvIsImplicitByRef)
          {
              assert(varDsc->lvIsParam);
  
              assert(varTypeIsStruct(varDsc) || (varDsc->lvType == TYP_BYREF));
              return true;
          }
  #endif // defined(TARGET_AMD64) || defined(TARGET_ARM64)
          return false;
      }
  
      // Returns true if this local var is a multireg struct
      bool lvaIsMultiregStruct(LclVarDsc* varDsc, bool isVararg);
  
      // If the local is a TYP_STRUCT, get/set a class handle describing it
      CORINFO_CLASS_HANDLE lvaGetStruct(unsigned varNum);
      void lvaSetStruct(unsigned varNum, CORINFO_CLASS_HANDLE typeHnd, bool unsafeValueClsCheck, bool setTypeInfo = true);
      void lvaSetStructUsedAsVarArg(unsigned varNum);
  
      // If the local is TYP_REF, set or update the associated class information.
      void lvaSetClass(unsigned varNum, CORINFO_CLASS_HANDLE clsHnd, bool isExact = false);
      void lvaSetClass(unsigned varNum, GenTree* tree, CORINFO_CLASS_HANDLE stackHandle = nullptr);
      void lvaUpdateClass(unsigned varNum, CORINFO_CLASS_HANDLE clsHnd, bool isExact = false);
      void lvaUpdateClass(unsigned varNum, GenTree* tree, CORINFO_CLASS_HANDLE stackHandle = nullptr);
  
  #define MAX_NumOfFieldsInPromotableStruct 4 // Maximum number of fields in promotable struct
  
      // Info about struct type fields.
      struct lvaStructFieldInfo
      {
          CORINFO_FIELD_HANDLE fldHnd;
          unsigned char        fldOffset;
          unsigned char        fldOrdinal;
          var_types            fldType;
          unsigned             fldSize;
          CORINFO_CLASS_HANDLE fldTypeHnd;
  
          lvaStructFieldInfo()
              : fldHnd(nullptr), fldOffset(0), fldOrdinal(0), fldType(TYP_UNDEF), fldSize(0), fldTypeHnd(nullptr)
          {
          }
      };
  
      // Info about a struct type, instances of which may be candidates for promotion.
      struct lvaStructPromotionInfo
      {
          CORINFO_CLASS_HANDLE typeHnd;
          bool                 canPromote;
          bool                 containsHoles;
          bool                 customLayout;
          bool                 fieldsSorted;
          unsigned char        fieldCnt;
          lvaStructFieldInfo   fields[MAX_NumOfFieldsInPromotableStruct];
  
          lvaStructPromotionInfo(CORINFO_CLASS_HANDLE typeHnd = nullptr)
              : typeHnd(typeHnd)
              , canPromote(false)
              , containsHoles(false)
              , customLayout(false)
              , fieldsSorted(false)
              , fieldCnt(0)
          {
          }
      };
  
      struct lvaFieldOffsetCmp
      {
          bool operator()(const lvaStructFieldInfo& field1, const lvaStructFieldInfo& field2);
      };
  
      // This class is responsible for checking validity and profitability of struct promotion.
      // If it is both legal and profitable, then TryPromoteStructVar promotes the struct and initializes
      // nessesary information for fgMorphStructField to use.
      class StructPromotionHelper
      {
      public:
          StructPromotionHelper(Compiler* compiler);
  
          bool CanPromoteStructType(CORINFO_CLASS_HANDLE typeHnd);
          bool TryPromoteStructVar(unsigned lclNum);
          void Clear()
          {
              structPromotionInfo.typeHnd = NO_CLASS_HANDLE;
          }
  
  #ifdef DEBUG
          void CheckRetypedAsScalar(CORINFO_FIELD_HANDLE fieldHnd, var_types requestedType);
  #endif // DEBUG
  
      private:
          bool CanPromoteStructVar(unsigned lclNum);
          bool ShouldPromoteStructVar(unsigned lclNum);
          void PromoteStructVar(unsigned lclNum);
          void SortStructFields();
  
          lvaStructFieldInfo GetFieldInfo(CORINFO_FIELD_HANDLE fieldHnd, BYTE ordinal);
          bool TryPromoteStructField(lvaStructFieldInfo& outerFieldInfo);
  
      private:
          Compiler*              compiler;
          lvaStructPromotionInfo structPromotionInfo;
  
  #ifdef DEBUG
          typedef JitHashTable<CORINFO_FIELD_HANDLE, JitPtrKeyFuncs<CORINFO_FIELD_STRUCT_>, var_types>
                                   RetypedAsScalarFieldsMap;
          RetypedAsScalarFieldsMap retypedFieldsMap;
  #endif // DEBUG
      };
  
      StructPromotionHelper* structPromotionHelper;
  
      unsigned lvaGetFieldLocal(const LclVarDsc* varDsc, unsigned int fldOffset);
      lvaPromotionType lvaGetPromotionType(const LclVarDsc* varDsc);
      lvaPromotionType lvaGetPromotionType(unsigned varNum);
      lvaPromotionType lvaGetParentPromotionType(const LclVarDsc* varDsc);
      lvaPromotionType lvaGetParentPromotionType(unsigned varNum);
      bool lvaIsFieldOfDependentlyPromotedStruct(const LclVarDsc* varDsc);
      bool lvaIsGCTracked(const LclVarDsc* varDsc);
  
  #if defined(FEATURE_SIMD)
      bool lvaMapSimd12ToSimd16(const LclVarDsc* varDsc)
      {
          assert(varDsc->lvType == TYP_SIMD12);
          assert(varDsc->lvExactSize == 12);
  
  #if defined(TARGET_64BIT)
          assert(compMacOsArm64Abi() || varDsc->lvSize() == 16);
  #endif // defined(TARGET_64BIT)
  
          // We make local variable SIMD12 types 16 bytes instead of just 12.
          // lvSize() will return 16 bytes for SIMD12, even for fields.
          // However, we can't do that mapping if the var is a dependently promoted struct field.
          // Such a field must remain its exact size within its parent struct unless it is a single
          // field *and* it is the only field in a struct of 16 bytes.
          if (varDsc->lvSize() != 16)
          {
              return false;
          }
          if (lvaIsFieldOfDependentlyPromotedStruct(varDsc))
          {
              LclVarDsc* parentVarDsc = lvaGetDesc(varDsc->lvParentLcl);
              return (parentVarDsc->lvFieldCnt == 1) && (parentVarDsc->lvSize() == 16);
          }
          return true;
      }
  #endif // defined(FEATURE_SIMD)
  
      unsigned lvaGSSecurityCookie; // LclVar number
      bool     lvaTempsHaveLargerOffsetThanVars();
  
      // Returns "true" iff local variable "lclNum" is in SSA form.
      bool lvaInSsa(unsigned lclNum)
      {
          assert(lclNum < lvaCount);
          return lvaTable[lclNum].lvInSsa;
      }
  
      unsigned lvaStubArgumentVar; // variable representing the secret stub argument coming in EAX
  
  #if defined(FEATURE_EH_FUNCLETS)
      unsigned lvaPSPSym; // variable representing the PSPSym
  #endif
  
      InlineInfo*     impInlineInfo; // Only present for inlinees
      InlineStrategy* m_inlineStrategy;
  
      InlineContext* compInlineContext; // Always present
  
      // The Compiler* that is the root of the inlining tree of which "this" is a member.
      Compiler* impInlineRoot();
  
  #if defined(DEBUG) || defined(INLINE_DATA)
      unsigned __int64 getInlineCycleCount()
      {
          return m_compCycles;
      }
  #endif // defined(DEBUG) || defined(INLINE_DATA)
  
      bool fgNoStructPromotion;      // Set to TRUE to turn off struct promotion for this method.
      bool fgNoStructParamPromotion; // Set to TRUE to turn off struct promotion for parameters this method.
  
      //=========================================================================
      //                          PROTECTED
      //=========================================================================
  
  protected:
      //---------------- Local variable ref-counting ----------------------------
  
      void lvaMarkLclRefs(GenTree* tree, BasicBlock* block, Statement* stmt, bool isRecompute);
      bool IsDominatedByExceptionalEntry(BasicBlock* block);
      void SetVolatileHint(LclVarDsc* varDsc);
  
      // Keeps the mapping from SSA #'s to VN's for the implicit memory variables.
      SsaDefArray<SsaMemDef> lvMemoryPerSsaData;
  
  public:
      // Returns the address of the per-Ssa data for memory at the given ssaNum (which is required
      // not to be the SsaConfig::RESERVED_SSA_NUM, which indicates that the variable is
      // not an SSA variable).
      SsaMemDef* GetMemoryPerSsaData(unsigned ssaNum)
      {
          return lvMemoryPerSsaData.GetSsaDef(ssaNum);
      }
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           Importer                                        XX
      XX                                                                           XX
      XX   Imports the given method and converts it to semantic trees              XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  private:
      // For prefixFlags
      enum
      {
          PREFIX_TAILCALL_EXPLICIT = 0x00000001, // call has "tail" IL prefix
          PREFIX_TAILCALL_IMPLICIT =
              0x00000010, // call is treated as having "tail" prefix even though there is no "tail" IL prefix
          PREFIX_TAILCALL_STRESS =
              0x00000100, // call doesn't "tail" IL prefix but is treated as explicit because of tail call stress
          PREFIX_TAILCALL    = (PREFIX_TAILCALL_EXPLICIT | PREFIX_TAILCALL_IMPLICIT | PREFIX_TAILCALL_STRESS),
          PREFIX_VOLATILE    = 0x00001000,
          PREFIX_UNALIGNED   = 0x00010000,
          PREFIX_CONSTRAINED = 0x00100000,
          PREFIX_READONLY    = 0x01000000
      };
  
      static void impValidateMemoryAccessOpcode(const BYTE* codeAddr, const BYTE* codeEndp, bool volatilePrefix);
      static OPCODE impGetNonPrefixOpcode(const BYTE* codeAddr, const BYTE* codeEndp);
      static bool impOpcodeIsCallOpcode(OPCODE opcode);
  
  public:
      void impInit();
      void impImport();
  
      CORINFO_CLASS_HANDLE impGetRefAnyClass();
      CORINFO_CLASS_HANDLE impGetRuntimeArgumentHandle();
      CORINFO_CLASS_HANDLE impGetTypeHandleClass();
      CORINFO_CLASS_HANDLE impGetStringClass();
      CORINFO_CLASS_HANDLE impGetObjectClass();
  
      // Returns underlying type of handles returned by ldtoken instruction
      var_types GetRuntimeHandleUnderlyingType()
      {
          // RuntimeTypeHandle is backed by raw pointer on CoreRT and by object reference on other runtimes
          return IsTargetAbi(CORINFO_CORERT_ABI) ? TYP_I_IMPL : TYP_REF;
      }
  
      void impDevirtualizeCall(GenTreeCall*            call,
                               CORINFO_RESOLVED_TOKEN* pResolvedToken,
                               CORINFO_METHOD_HANDLE*  method,
                               unsigned*               methodFlags,
                               CORINFO_CONTEXT_HANDLE* contextHandle,
                               CORINFO_CONTEXT_HANDLE* exactContextHandle,
                               bool                    isLateDevirtualization,
                               bool                    isExplicitTailCall,
                               IL_OFFSET               ilOffset = BAD_IL_OFFSET);
  
      //=========================================================================
      //                          PROTECTED
      //=========================================================================
  
  protected:
      //-------------------- Stack manipulation ---------------------------------
  
      unsigned impStkSize; // Size of the full stack
  
  #define SMALL_STACK_SIZE 16 // number of elements in impSmallStack
  
      struct SavedStack // used to save/restore stack contents.
      {
          unsigned    ssDepth; // number of values on stack
          StackEntry* ssTrees; // saved tree values
      };
  
      bool impIsPrimitive(CorInfoType type);
      bool impILConsumesAddr(const BYTE* codeAddr);
  
      void impResolveToken(const BYTE* addr, CORINFO_RESOLVED_TOKEN* pResolvedToken, CorInfoTokenKind kind);
  
      void impPushOnStack(GenTree* tree, typeInfo ti);
      void        impPushNullObjRefOnStack();
      StackEntry  impPopStack();
      StackEntry& impStackTop(unsigned n = 0);
      unsigned impStackHeight();
  
      void impSaveStackState(SavedStack* savePtr, bool copy);
      void impRestoreStackState(SavedStack* savePtr);
  
      GenTree* impImportLdvirtftn(GenTree* thisPtr, CORINFO_RESOLVED_TOKEN* pResolvedToken, CORINFO_CALL_INFO* pCallInfo);
  
      int impBoxPatternMatch(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                             const BYTE*             codeAddr,
                             const BYTE*             codeEndp,
                             bool                    makeInlineObservation = false);
      void impImportAndPushBox(CORINFO_RESOLVED_TOKEN* pResolvedToken);
  
      void impImportNewObjArray(CORINFO_RESOLVED_TOKEN* pResolvedToken, CORINFO_CALL_INFO* pCallInfo);
  
      bool impCanPInvokeInline();
      bool impCanPInvokeInlineCallSite(BasicBlock* block);
      void impCheckForPInvokeCall(
          GenTreeCall* call, CORINFO_METHOD_HANDLE methHnd, CORINFO_SIG_INFO* sig, unsigned mflags, BasicBlock* block);
      GenTreeCall* impImportIndirectCall(CORINFO_SIG_INFO* sig, const DebugInfo& di = DebugInfo());
      void impPopArgsForUnmanagedCall(GenTree* call, CORINFO_SIG_INFO* sig);
  
      void impInsertHelperCall(CORINFO_HELPER_DESC* helperCall);
      void impHandleAccessAllowed(CorInfoIsAccessAllowedResult result, CORINFO_HELPER_DESC* helperCall);
      void impHandleAccessAllowedInternal(CorInfoIsAccessAllowedResult result, CORINFO_HELPER_DESC* helperCall);
  
      var_types impImportCall(OPCODE                  opcode,
                              CORINFO_RESOLVED_TOKEN* pResolvedToken,
                              CORINFO_RESOLVED_TOKEN* pConstrainedResolvedToken, // Is this a "constrained." call on a
                                                                                 // type parameter?
                              GenTree*           newobjThis,
                              int                prefixFlags,
                              CORINFO_CALL_INFO* callInfo,
                              IL_OFFSET          rawILOffset);
  
      CORINFO_CLASS_HANDLE impGetSpecialIntrinsicExactReturnType(CORINFO_METHOD_HANDLE specialIntrinsicHandle);
  
      bool impMethodInfo_hasRetBuffArg(CORINFO_METHOD_INFO* methInfo, CorInfoCallConvExtension callConv);
  
      GenTree* impFixupCallStructReturn(GenTreeCall* call, CORINFO_CLASS_HANDLE retClsHnd);
  
      GenTree* impFixupStructReturnType(GenTree*                 op,
                                        CORINFO_CLASS_HANDLE     retClsHnd,
                                        CorInfoCallConvExtension unmgdCallConv);
  
  #ifdef DEBUG
      var_types impImportJitTestLabelMark(int numArgs);
  #endif // DEBUG
  
      GenTree* impInitClass(CORINFO_RESOLVED_TOKEN* pResolvedToken);
  
      GenTree* impImportStaticReadOnlyField(void* fldAddr, var_types lclTyp);
  
      GenTree* impImportStaticFieldAccess(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                          CORINFO_ACCESS_FLAGS    access,
                                          CORINFO_FIELD_INFO*     pFieldInfo,
                                          var_types               lclTyp);
  
      static void impBashVarAddrsToI(GenTree* tree1, GenTree* tree2 = nullptr);
  
      GenTree* impImplicitIorI4Cast(GenTree* tree, var_types dstTyp);
  
      GenTree* impImplicitR4orR8Cast(GenTree* tree, var_types dstTyp);
  
      void impImportLeave(BasicBlock* block);
      void impResetLeaveBlock(BasicBlock* block, unsigned jmpAddr);
      GenTree* impTypeIsAssignable(GenTree* typeTo, GenTree* typeFrom);
  
      GenTree* impIntrinsic(GenTree*                newobjThis,
                            CORINFO_CLASS_HANDLE    clsHnd,
                            CORINFO_METHOD_HANDLE   method,
                            CORINFO_SIG_INFO*       sig,
                            unsigned                methodFlags,
                            int                     memberRef,
                            bool                    readonlyCall,
                            bool                    tailCall,
                            CORINFO_RESOLVED_TOKEN* pContstrainedResolvedToken,
                            CORINFO_THIS_TRANSFORM  constraintCallThisTransform,
                            NamedIntrinsic*         pIntrinsicName,
                            bool*                   isSpecialIntrinsic = nullptr);
      GenTree* impMathIntrinsic(CORINFO_METHOD_HANDLE method,
                                CORINFO_SIG_INFO*     sig,
                                var_types             callType,
                                NamedIntrinsic        intrinsicName,
                                bool                  tailCall);
      NamedIntrinsic lookupNamedIntrinsic(CORINFO_METHOD_HANDLE method);
      GenTree* impUnsupportedNamedIntrinsic(unsigned              helper,
                                            CORINFO_METHOD_HANDLE method,
                                            CORINFO_SIG_INFO*     sig,
                                            bool                  mustExpand);
  
  #ifdef FEATURE_HW_INTRINSICS
      GenTree* impHWIntrinsic(NamedIntrinsic        intrinsic,
                              CORINFO_CLASS_HANDLE  clsHnd,
                              CORINFO_METHOD_HANDLE method,
                              CORINFO_SIG_INFO*     sig,
                              bool                  mustExpand);
      GenTree* impSimdAsHWIntrinsic(NamedIntrinsic        intrinsic,
                                    CORINFO_CLASS_HANDLE  clsHnd,
                                    CORINFO_METHOD_HANDLE method,
                                    CORINFO_SIG_INFO*     sig,
                                    GenTree*              newobjThis);
  
  protected:
      bool compSupportsHWIntrinsic(CORINFO_InstructionSet isa);
  
      GenTree* impSimdAsHWIntrinsicSpecial(NamedIntrinsic       intrinsic,
                                           CORINFO_CLASS_HANDLE clsHnd,
                                           CORINFO_SIG_INFO*    sig,
                                           var_types            retType,
                                           CorInfoType          simdBaseJitType,
                                           unsigned             simdSize,
                                           GenTree*             newobjThis);
  
      GenTree* impSpecialIntrinsic(NamedIntrinsic        intrinsic,
                                   CORINFO_CLASS_HANDLE  clsHnd,
                                   CORINFO_METHOD_HANDLE method,
                                   CORINFO_SIG_INFO*     sig,
                                   CorInfoType           simdBaseJitType,
                                   var_types             retType,
                                   unsigned              simdSize);
  
      GenTree* getArgForHWIntrinsic(var_types            argType,
                                    CORINFO_CLASS_HANDLE argClass,
                                    bool                 expectAddr = false,
                                    GenTree*             newobjThis = nullptr);
      GenTree* impNonConstFallback(NamedIntrinsic intrinsic, var_types simdType, CorInfoType simdBaseJitType);
      GenTree* addRangeCheckIfNeeded(
          NamedIntrinsic intrinsic, GenTree* immOp, bool mustExpand, int immLowerBound, int immUpperBound);
      GenTree* addRangeCheckForHWIntrinsic(GenTree* immOp, int immLowerBound, int immUpperBound);
  
  #ifdef TARGET_XARCH
      GenTree* impBaseIntrinsic(NamedIntrinsic        intrinsic,
                                CORINFO_CLASS_HANDLE  clsHnd,
                                CORINFO_METHOD_HANDLE method,
                                CORINFO_SIG_INFO*     sig,
                                CorInfoType           simdBaseJitType,
                                var_types             retType,
                                unsigned              simdSize);
      GenTree* impSSEIntrinsic(NamedIntrinsic intrinsic, CORINFO_METHOD_HANDLE method, CORINFO_SIG_INFO* sig);
      GenTree* impSSE2Intrinsic(NamedIntrinsic intrinsic, CORINFO_METHOD_HANDLE method, CORINFO_SIG_INFO* sig);
      GenTree* impAvxOrAvx2Intrinsic(NamedIntrinsic intrinsic, CORINFO_METHOD_HANDLE method, CORINFO_SIG_INFO* sig);
      GenTree* impBMI1OrBMI2Intrinsic(NamedIntrinsic intrinsic, CORINFO_METHOD_HANDLE method, CORINFO_SIG_INFO* sig);
  #endif // TARGET_XARCH
  #endif // FEATURE_HW_INTRINSICS
      GenTree* impArrayAccessIntrinsic(CORINFO_CLASS_HANDLE clsHnd,
                                       CORINFO_SIG_INFO*    sig,
                                       int                  memberRef,
                                       bool                 readonlyCall,
                                       NamedIntrinsic       intrinsicName);
      GenTree* impInitializeArrayIntrinsic(CORINFO_SIG_INFO* sig);
      GenTree* impCreateSpanIntrinsic(CORINFO_SIG_INFO* sig);
  
      GenTree* impKeepAliveIntrinsic(GenTree* objToKeepAlive);
  
      GenTree* impMethodPointer(CORINFO_RESOLVED_TOKEN* pResolvedToken, CORINFO_CALL_INFO* pCallInfo);
  
      GenTree* impTransformThis(GenTree*                thisPtr,
                                CORINFO_RESOLVED_TOKEN* pConstrainedResolvedToken,
                                CORINFO_THIS_TRANSFORM  transform);
  
      //----------------- Manipulating the trees and stmts ----------------------
  
      Statement* impStmtList; // Statements for the BB being imported.
      Statement* impLastStmt; // The last statement for the current BB.
  
  public:
      enum
      {
          CHECK_SPILL_ALL  = -1,
          CHECK_SPILL_NONE = -2
      };
  
      void impBeginTreeList();
      void impEndTreeList(BasicBlock* block, Statement* firstStmt, Statement* lastStmt);
      void impEndTreeList(BasicBlock* block);
      void impAppendStmtCheck(Statement* stmt, unsigned chkLevel);
      void impAppendStmt(Statement* stmt, unsigned chkLevel, bool checkConsumedDebugInfo = true);
      void impAppendStmt(Statement* stmt);
      void impInsertStmtBefore(Statement* stmt, Statement* stmtBefore);
      Statement* impAppendTree(GenTree* tree, unsigned chkLevel, const DebugInfo& di, bool checkConsumedDebugInfo = true);
      void impInsertTreeBefore(GenTree* tree, const DebugInfo& di, Statement* stmtBefore);
      void impAssignTempGen(unsigned         tmp,
                            GenTree*         val,
                            unsigned         curLevel,
                            Statement**      pAfterStmt = nullptr,
                            const DebugInfo& di         = DebugInfo(),
                            BasicBlock*      block      = nullptr);
      void impAssignTempGen(unsigned             tmpNum,
                            GenTree*             val,
                            CORINFO_CLASS_HANDLE structHnd,
                            unsigned             curLevel,
                            Statement**          pAfterStmt = nullptr,
                            const DebugInfo&     di         = DebugInfo(),
                            BasicBlock*          block      = nullptr);
  
      Statement* impExtractLastStmt();
      GenTree* impCloneExpr(GenTree*             tree,
                            GenTree**            clone,
                            CORINFO_CLASS_HANDLE structHnd,
                            unsigned             curLevel,
                            Statement** pAfterStmt DEBUGARG(const char* reason));
      GenTree* impAssignStruct(GenTree*             dest,
                               GenTree*             src,
                               CORINFO_CLASS_HANDLE structHnd,
                               unsigned             curLevel,
                               Statement**          pAfterStmt = nullptr,
                               const DebugInfo&     di         = DebugInfo(),
                               BasicBlock*          block      = nullptr);
      GenTree* impAssignStructPtr(GenTree*             dest,
                                  GenTree*             src,
                                  CORINFO_CLASS_HANDLE structHnd,
                                  unsigned             curLevel,
                                  Statement**          pAfterStmt = nullptr,
                                  const DebugInfo&     di         = DebugInfo(),
                                  BasicBlock*          block      = nullptr);
  
      GenTree* impGetStructAddr(GenTree* structVal, CORINFO_CLASS_HANDLE structHnd, unsigned curLevel, bool willDeref);
  
      var_types impNormStructType(CORINFO_CLASS_HANDLE structHnd, CorInfoType* simdBaseJitType = nullptr);
  
      GenTree* impNormStructVal(GenTree*             structVal,
                                CORINFO_CLASS_HANDLE structHnd,
                                unsigned             curLevel,
                                bool                 forceNormalization = false);
  
      GenTree* impTokenToHandle(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                bool*                   pRuntimeLookup    = nullptr,
                                bool                    mustRestoreHandle = false,
                                bool                    importParent      = false);
  
      GenTree* impParentClassTokenToHandle(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                           bool*                   pRuntimeLookup    = nullptr,
                                           bool                    mustRestoreHandle = false)
      {
          return impTokenToHandle(pResolvedToken, pRuntimeLookup, mustRestoreHandle, true);
      }
  
      GenTree* impLookupToTree(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                               CORINFO_LOOKUP*         pLookup,
                               GenTreeFlags            flags,
                               void*                   compileTimeHandle);
  
      GenTree* getRuntimeContextTree(CORINFO_RUNTIME_LOOKUP_KIND kind);
  
      GenTree* impRuntimeLookupToTree(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                      CORINFO_LOOKUP*         pLookup,
                                      void*                   compileTimeHandle);
  
      GenTree* impReadyToRunLookupToTree(CORINFO_CONST_LOOKUP* pLookup, GenTreeFlags flags, void* compileTimeHandle);
  
      GenTreeCall* impReadyToRunHelperToTree(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                             CorInfoHelpFunc         helper,
                                             var_types               type,
                                             GenTreeCall::Use*       args               = nullptr,
                                             CORINFO_LOOKUP_KIND*    pGenericLookupKind = nullptr);
  
      GenTree* impCastClassOrIsInstToTree(GenTree*                op1,
                                          GenTree*                op2,
                                          CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                          bool                    isCastClass);
  
      GenTree* impOptimizeCastClassOrIsInst(GenTree* op1, CORINFO_RESOLVED_TOKEN* pResolvedToken, bool isCastClass);
  
      bool VarTypeIsMultiByteAndCanEnreg(var_types                type,
                                         CORINFO_CLASS_HANDLE     typeClass,
                                         unsigned*                typeSize,
                                         bool                     forReturn,
                                         bool                     isVarArg,
                                         CorInfoCallConvExtension callConv);
  
      bool IsIntrinsicImplementedByUserCall(NamedIntrinsic intrinsicName);
      bool IsTargetIntrinsic(NamedIntrinsic intrinsicName);
      bool IsMathIntrinsic(NamedIntrinsic intrinsicName);
      bool IsMathIntrinsic(GenTree* tree);
  
  private:
      //----------------- Importing the method ----------------------------------
  
      CORINFO_CONTEXT_HANDLE impTokenLookupContextHandle; // The context used for looking up tokens.
  
  #ifdef DEBUG
      unsigned    impCurOpcOffs;
      const char* impCurOpcName;
      bool        impNestedStackSpill;
  
      // For displaying instrs with generated native code (-n:B)
      Statement* impLastILoffsStmt; // oldest stmt added for which we did not call SetLastILOffset().
      void       impNoteLastILoffs();
  #endif
  
      // Debug info of current statement being imported. It gets set to contain
      // no IL location (!impCurStmtDI.GetLocation().IsValid) after it has been
      // set in the appended trees. Then it gets updated at IL instructions for
      // which we have to report mapping info.
      // It will always contain the current inline context.
      DebugInfo impCurStmtDI;
  
      DebugInfo impCreateDIWithCurrentStackInfo(IL_OFFSET offs, bool isCall);
      void impCurStmtOffsSet(IL_OFFSET offs);
  
      void impNoteBranchOffs();
  
      unsigned impInitBlockLineInfo();
  
      bool impIsThis(GenTree* obj);
      bool impIsLDFTN_TOKEN(const BYTE* delegateCreateStart, const BYTE* newobjCodeAddr);
      bool impIsDUP_LDVIRTFTN_TOKEN(const BYTE* delegateCreateStart, const BYTE* newobjCodeAddr);
      bool impIsAnySTLOC(OPCODE opcode)
      {
          return ((opcode == CEE_STLOC) || (opcode == CEE_STLOC_S) ||
                  ((opcode >= CEE_STLOC_0) && (opcode <= CEE_STLOC_3)));
      }
  
      GenTreeCall::Use* impPopCallArgs(unsigned count, CORINFO_SIG_INFO* sig, GenTreeCall::Use* prefixArgs = nullptr);
  
      bool impCheckImplicitArgumentCoercion(var_types sigType, var_types nodeType) const;
  
      GenTreeCall::Use* impPopReverseCallArgs(unsigned count, CORINFO_SIG_INFO* sig, unsigned skipReverseCount = 0);
  
      //---------------- Spilling the importer stack ----------------------------
  
      // The maximum number of bytes of IL processed without clean stack state.
      // It allows to limit the maximum tree size and depth.
      static const unsigned MAX_TREE_SIZE = 200;
      bool impCanSpillNow(OPCODE prevOpcode);
  
      struct PendingDsc
      {
          PendingDsc*   pdNext;
          BasicBlock*   pdBB;
          SavedStack    pdSavedStack;
          ThisInitState pdThisPtrInit;
      };
  
      PendingDsc* impPendingList; // list of BBs currently waiting to be imported.
      PendingDsc* impPendingFree; // Freed up dscs that can be reused
  
      // We keep a byte-per-block map (dynamically extended) in the top-level Compiler object of a compilation.
      JitExpandArray<BYTE> impPendingBlockMembers;
  
      // Return the byte for "b" (allocating/extending impPendingBlockMembers if necessary.)
      // Operates on the map in the top-level ancestor.
      BYTE impGetPendingBlockMember(BasicBlock* blk)
      {
          return impInlineRoot()->impPendingBlockMembers.Get(blk->bbInd());
      }
  
      // Set the byte for "b" to "val" (allocating/extending impPendingBlockMembers if necessary.)
      // Operates on the map in the top-level ancestor.
      void impSetPendingBlockMember(BasicBlock* blk, BYTE val)
      {
          impInlineRoot()->impPendingBlockMembers.Set(blk->bbInd(), val);
      }
  
      bool impCanReimport;
  
      bool impSpillStackEntry(unsigned level,
                              unsigned varNum
  #ifdef DEBUG
                              ,
                              bool        bAssertOnRecursion,
                              const char* reason
  #endif
                              );
  
      void impSpillStackEnsure(bool spillLeaves = false);
      void impEvalSideEffects();
      void impSpillSpecialSideEff();
      void impSpillSideEffects(bool spillGlobEffects, unsigned chkLevel DEBUGARG(const char* reason));
      void               impSpillValueClasses();
      void               impSpillEvalStack();
      static fgWalkPreFn impFindValueClasses;
      void impSpillLclRefs(ssize_t lclNum);
  
      BasicBlock* impPushCatchArgOnStack(BasicBlock* hndBlk, CORINFO_CLASS_HANDLE clsHnd, bool isSingleBlockFilter);
  
      bool impBlockIsInALoop(BasicBlock* block);
      void impImportBlockCode(BasicBlock* block);
  
      void impReimportMarkBlock(BasicBlock* block);
      void impReimportMarkSuccessors(BasicBlock* block);
  
      void impVerifyEHBlock(BasicBlock* block, bool isTryStart);
  
      void impImportBlockPending(BasicBlock* block);
  
      // Similar to impImportBlockPending, but assumes that block has already been imported once and is being
      // reimported for some reason.  It specifically does *not* look at verCurrentState to set the EntryState
      // for the block, but instead, just re-uses the block's existing EntryState.
      void impReimportBlockPending(BasicBlock* block);
  
      var_types impGetByRefResultType(genTreeOps oper, bool fUnsigned, GenTree** pOp1, GenTree** pOp2);
  
      void impImportBlock(BasicBlock* block);
  
      // Assumes that "block" is a basic block that completes with a non-empty stack. We will assign the values
      // on the stack to local variables (the "spill temp" variables). The successor blocks will assume that
      // its incoming stack contents are in those locals. This requires "block" and its successors to agree on
      // the variables that will be used -- and for all the predecessors of those successors, and the
      // successors of those predecessors, etc. Call such a set of blocks closed under alternating
      // successor/predecessor edges a "spill clique." A block is a "predecessor" or "successor" member of the
      // clique (or, conceivably, both). Each block has a specified sequence of incoming and outgoing spill
      // temps. If "block" already has its outgoing spill temps assigned (they are always a contiguous series
      // of local variable numbers, so we represent them with the base local variable number), returns that.
      // Otherwise, picks a set of spill temps, and propagates this choice to all blocks in the spill clique of
      // which "block" is a member (asserting, in debug mode, that no block in this clique had its spill temps
      // chosen already. More precisely, that the incoming or outgoing spill temps are not chosen, depending
      // on which kind of member of the clique the block is).
      unsigned impGetSpillTmpBase(BasicBlock* block);
  
      // Assumes that "block" is a basic block that completes with a non-empty stack. We have previously
      // assigned the values on the stack to local variables (the "spill temp" variables). The successor blocks
      // will assume that its incoming stack contents are in those locals. This requires "block" and its
      // successors to agree on the variables and their types that will be used.  The CLI spec allows implicit
      // conversions between 'int' and 'native int' or 'float' and 'double' stack types. So one predecessor can
      // push an int and another can push a native int.  For 64-bit we have chosen to implement this by typing
      // the "spill temp" as native int, and then importing (or re-importing as needed) so that all the
      // predecessors in the "spill clique" push a native int (sign-extending if needed), and all the
      // successors receive a native int. Similarly float and double are unified to double.
      // This routine is called after a type-mismatch is detected, and it will walk the spill clique to mark
      // blocks for re-importation as appropriate (both successors, so they get the right incoming type, and
      // predecessors, so they insert an upcast if needed).
      void impReimportSpillClique(BasicBlock* block);
  
      // When we compute a "spill clique" (see above) these byte-maps are allocated to have a byte per basic
      // block, and represent the predecessor and successor members of the clique currently being computed.
      // *** Access to these will need to be locked in a parallel compiler.
      JitExpandArray<BYTE> impSpillCliquePredMembers;
      JitExpandArray<BYTE> impSpillCliqueSuccMembers;
  
      enum SpillCliqueDir
      {
          SpillCliquePred,
          SpillCliqueSucc
      };
  
      // Abstract class for receiving a callback while walking a spill clique
      class SpillCliqueWalker
      {
      public:
          virtual void Visit(SpillCliqueDir predOrSucc, BasicBlock* blk) = 0;
      };
  
      // This class is used for setting the bbStkTempsIn and bbStkTempsOut on the blocks within a spill clique
      class SetSpillTempsBase : public SpillCliqueWalker
      {
          unsigned m_baseTmp;
  
      public:
          SetSpillTempsBase(unsigned baseTmp) : m_baseTmp(baseTmp)
          {
          }
          virtual void Visit(SpillCliqueDir predOrSucc, BasicBlock* blk);
      };
  
      // This class is used for implementing impReimportSpillClique part on each block within the spill clique
      class ReimportSpillClique : public SpillCliqueWalker
      {
          Compiler* m_pComp;
  
      public:
          ReimportSpillClique(Compiler* pComp) : m_pComp(pComp)
          {
          }
          virtual void Visit(SpillCliqueDir predOrSucc, BasicBlock* blk);
      };
  
      // This is the heart of the algorithm for walking spill cliques. It invokes callback->Visit for each
      // predecessor or successor within the spill clique
      void impWalkSpillCliqueFromPred(BasicBlock* pred, SpillCliqueWalker* callback);
  
      // For a BasicBlock that has already been imported, the EntryState has an array of GenTrees for the
      // incoming locals. This walks that list an resets the types of the GenTrees to match the types of
      // the VarDscs. They get out of sync when we have int/native int issues (see impReimportSpillClique).
      void impRetypeEntryStateTemps(BasicBlock* blk);
  
      BYTE impSpillCliqueGetMember(SpillCliqueDir predOrSucc, BasicBlock* blk);
      void impSpillCliqueSetMember(SpillCliqueDir predOrSucc, BasicBlock* blk, BYTE val);
  
      void impPushVar(GenTree* op, typeInfo tiRetVal);
      GenTreeLclVar* impCreateLocalNode(unsigned lclNum DEBUGARG(IL_OFFSET offset));
      void impLoadVar(unsigned lclNum, IL_OFFSET offset, const typeInfo& tiRetVal);
      void impLoadVar(unsigned lclNum, IL_OFFSET offset)
      {
          impLoadVar(lclNum, offset, lvaGetDesc(lclNum)->lvVerTypeInfo);
      }
      void impLoadArg(unsigned ilArgNum, IL_OFFSET offset);
      void impLoadLoc(unsigned ilLclNum, IL_OFFSET offset);
      bool impReturnInstruction(int prefixFlags, OPCODE& opcode);
  
  #ifdef TARGET_ARM
      void impMarkLclDstNotPromotable(unsigned tmpNum, GenTree* op, CORINFO_CLASS_HANDLE hClass);
  #endif
  
      // A free list of linked list nodes used to represent to-do stacks of basic blocks.
      struct BlockListNode
      {
          BasicBlock*    m_blk;
          BlockListNode* m_next;
          BlockListNode(BasicBlock* blk, BlockListNode* next = nullptr) : m_blk(blk), m_next(next)
          {
          }
          void* operator new(size_t sz, Compiler* comp);
      };
      BlockListNode* impBlockListNodeFreeList;
  
      void FreeBlockListNode(BlockListNode* node);
  
      bool impIsValueType(typeInfo* pTypeInfo);
      var_types mangleVarArgsType(var_types type);
  
      regNumber getCallArgIntRegister(regNumber floatReg);
      regNumber getCallArgFloatRegister(regNumber intReg);
  
  #if defined(DEBUG)
      static unsigned jitTotalMethodCompiled;
  #endif
  
  #ifdef DEBUG
      static LONG jitNestingLevel;
  #endif // DEBUG
  
      static bool impIsAddressInLocal(const GenTree* tree, GenTree** lclVarTreeOut = nullptr);
  
      void impMakeDiscretionaryInlineObservations(InlineInfo* pInlineInfo, InlineResult* inlineResult);
  
      // STATIC inlining decision based on the IL code.
      void impCanInlineIL(CORINFO_METHOD_HANDLE fncHandle,
                          CORINFO_METHOD_INFO*  methInfo,
                          bool                  forceInline,
                          InlineResult*         inlineResult);
  
      void impCheckCanInline(GenTreeCall*           call,
                             CORINFO_METHOD_HANDLE  fncHandle,
                             unsigned               methAttr,
                             CORINFO_CONTEXT_HANDLE exactContextHnd,
                             InlineCandidateInfo**  ppInlineCandidateInfo,
                             InlineResult*          inlineResult);
  
      void impInlineRecordArgInfo(InlineInfo*   pInlineInfo,
                                  GenTree*      curArgVal,
                                  unsigned      argNum,
                                  InlineResult* inlineResult);
  
      void impInlineInitVars(InlineInfo* pInlineInfo);
  
      unsigned impInlineFetchLocal(unsigned lclNum DEBUGARG(const char* reason));
  
      GenTree* impInlineFetchArg(unsigned lclNum, InlArgInfo* inlArgInfo, InlLclVarInfo* lclTypeInfo);
  
      bool impInlineIsThis(GenTree* tree, InlArgInfo* inlArgInfo);
  
      bool impInlineIsGuaranteedThisDerefBeforeAnySideEffects(GenTree*          additionalTree,
                                                              GenTreeCall::Use* additionalCallArgs,
                                                              GenTree*          dereferencedAddress,
                                                              InlArgInfo*       inlArgInfo);
  
      void impMarkInlineCandidate(GenTree*               call,
                                  CORINFO_CONTEXT_HANDLE exactContextHnd,
                                  bool                   exactContextNeedsRuntimeLookup,
                                  CORINFO_CALL_INFO*     callInfo);
  
      void impMarkInlineCandidateHelper(GenTreeCall*           call,
                                        CORINFO_CONTEXT_HANDLE exactContextHnd,
                                        bool                   exactContextNeedsRuntimeLookup,
                                        CORINFO_CALL_INFO*     callInfo);
  
      bool impTailCallRetTypeCompatible(bool                     allowWidening,
                                        var_types                callerRetType,
                                        CORINFO_CLASS_HANDLE     callerRetTypeClass,
                                        CorInfoCallConvExtension callerCallConv,
                                        var_types                calleeRetType,
                                        CORINFO_CLASS_HANDLE     calleeRetTypeClass,
                                        CorInfoCallConvExtension calleeCallConv);
  
      bool impIsTailCallILPattern(
          bool tailPrefixed, OPCODE curOpcode, const BYTE* codeAddrOfNextOpcode, const BYTE* codeEnd, bool isRecursive);
  
      bool impIsImplicitTailCallCandidate(
          OPCODE curOpcode, const BYTE* codeAddrOfNextOpcode, const BYTE* codeEnd, int prefixFlags, bool isRecursive);
  
      bool impIsClassExact(CORINFO_CLASS_HANDLE classHnd);
      bool impCanSkipCovariantStoreCheck(GenTree* value, GenTree* array);
  
      CORINFO_RESOLVED_TOKEN* impAllocateToken(const CORINFO_RESOLVED_TOKEN& token);
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           FlowGraph                                       XX
      XX                                                                           XX
      XX   Info about the basic-blocks, their contents and the flow analysis       XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      BasicBlock* fgFirstBB;        // Beginning of the basic block list
      BasicBlock* fgLastBB;         // End of the basic block list
      BasicBlock* fgFirstColdBlock; // First block to be placed in the cold section
      BasicBlock* fgEntryBB;        // For OSR, the original method's entry point
      BasicBlock* fgOSREntryBB;     // For OSR, the logical entry point (~ patchpoint)
  #if defined(FEATURE_EH_FUNCLETS)
      BasicBlock* fgFirstFuncletBB; // First block of outlined funclets (to allow block insertion before the funclets)
  #endif
      BasicBlock* fgFirstBBScratch;   // Block inserted for initialization stuff. Is nullptr if no such block has been
                                      // created.
      BasicBlockList* fgReturnBlocks; // list of BBJ_RETURN blocks
      unsigned        fgEdgeCount;    // # of control flow edges between the BBs
      unsigned        fgBBcount;      // # of BBs in the method
  #ifdef DEBUG
      unsigned fgBBcountAtCodegen; // # of BBs in the method at the start of codegen
  #endif
      unsigned     fgBBNumMax;       // The max bbNum that has been assigned to basic blocks
      unsigned     fgDomBBcount;     // # of BBs for which we have dominator and reachability information
      BasicBlock** fgBBInvPostOrder; // The flow graph stored in an array sorted in topological order, needed to compute
                                     // dominance. Indexed by block number. Size: fgBBNumMax + 1.
  
      // After the dominance tree is computed, we cache a DFS preorder number and DFS postorder number to compute
      // dominance queries in O(1). fgDomTreePreOrder and fgDomTreePostOrder are arrays giving the block's preorder and
      // postorder number, respectively. The arrays are indexed by basic block number. (Note that blocks are numbered
      // starting from one. Thus, we always waste element zero. This makes debugging easier and makes the code less likely
      // to suffer from bugs stemming from forgetting to add or subtract one from the block number to form an array
      // index). The arrays are of size fgBBNumMax + 1.
      unsigned* fgDomTreePreOrder;
      unsigned* fgDomTreePostOrder;
  
      // Dominator tree used by SSA construction and copy propagation (the two are expected to use the same tree
      // in order to avoid the need for SSA reconstruction and an "out of SSA" phase).
      DomTreeNode* fgSsaDomTree;
  
      bool fgBBVarSetsInited;
  
      // Allocate array like T* a = new T[fgBBNumMax + 1];
      // Using helper so we don't keep forgetting +1.
      template <typename T>
      T* fgAllocateTypeForEachBlk(CompMemKind cmk = CMK_Unknown)
      {
          return getAllocator(cmk).allocate<T>(fgBBNumMax + 1);
      }
  
      // BlockSets are relative to a specific set of BasicBlock numbers. If that changes
      // (if the blocks are renumbered), this changes. BlockSets from different epochs
      // cannot be meaningfully combined. Note that new blocks can be created with higher
      // block numbers without changing the basic block epoch. These blocks *cannot*
      // participate in a block set until the blocks are all renumbered, causing the epoch
      // to change. This is useful if continuing to use previous block sets is valuable.
      // If the epoch is zero, then it is uninitialized, and block sets can't be used.
      unsigned fgCurBBEpoch;
  
      unsigned GetCurBasicBlockEpoch()
      {
          return fgCurBBEpoch;
      }
  
      // The number of basic blocks in the current epoch. When the blocks are renumbered,
      // this is fgBBcount. As blocks are added, fgBBcount increases, fgCurBBEpochSize remains
      // the same, until a new BasicBlock epoch is created, such as when the blocks are all renumbered.
      unsigned fgCurBBEpochSize;
  
      // The number of "size_t" elements required to hold a bitset large enough for fgCurBBEpochSize
      // bits. This is precomputed to avoid doing math every time BasicBlockBitSetTraits::GetArrSize() is called.
      unsigned fgBBSetCountInSizeTUnits;
  
      void NewBasicBlockEpoch()
      {
          INDEBUG(unsigned oldEpochArrSize = fgBBSetCountInSizeTUnits);
  
          // We have a new epoch. Compute and cache the size needed for new BlockSets.
          fgCurBBEpoch++;
          fgCurBBEpochSize = fgBBNumMax + 1;
          fgBBSetCountInSizeTUnits =
              roundUp(fgCurBBEpochSize, (unsigned)(sizeof(size_t) * 8)) / unsigned(sizeof(size_t) * 8);
  
  #ifdef DEBUG
          // All BlockSet objects are now invalid!
          fgReachabilitySetsValid = false; // the bbReach sets are now invalid!
          fgEnterBlksSetValid     = false; // the fgEnterBlks set is now invalid!
  
          if (verbose)
          {
              unsigned epochArrSize = BasicBlockBitSetTraits::GetArrSize(this, sizeof(size_t));
              printf("\nNew BlockSet epoch %d, # of blocks (including unused BB00): %u, bitset array size: %u (%s)",
                     fgCurBBEpoch, fgCurBBEpochSize, epochArrSize, (epochArrSize <= 1) ? "short" : "long");
              if ((fgCurBBEpoch != 1) && ((oldEpochArrSize <= 1) != (epochArrSize <= 1)))
              {
                  // If we're not just establishing the first epoch, and the epoch array size has changed such that we're
                  // going to change our bitset representation from short (just a size_t bitset) to long (a pointer to an
                  // array of size_t bitsets), then print that out.
                  printf("; NOTE: BlockSet size was previously %s!", (oldEpochArrSize <= 1) ? "short" : "long");
              }
              printf("\n");
          }
  #endif // DEBUG
      }
  
      void EnsureBasicBlockEpoch()
      {
          if (fgCurBBEpochSize != fgBBNumMax + 1)
          {
              NewBasicBlockEpoch();
          }
      }
  
      BasicBlock* fgNewBasicBlock(BBjumpKinds jumpKind);
      void fgEnsureFirstBBisScratch();
      bool fgFirstBBisScratch();
      bool fgBBisScratch(BasicBlock* block);
  
      void fgExtendEHRegionBefore(BasicBlock* block);
      void fgExtendEHRegionAfter(BasicBlock* block);
  
      BasicBlock* fgNewBBbefore(BBjumpKinds jumpKind, BasicBlock* block, bool extendRegion);
  
      BasicBlock* fgNewBBafter(BBjumpKinds jumpKind, BasicBlock* block, bool extendRegion);
  
      BasicBlock* fgNewBBinRegion(BBjumpKinds jumpKind,
                                  unsigned    tryIndex,
                                  unsigned    hndIndex,
                                  BasicBlock* nearBlk,
                                  bool        putInFilter = false,
                                  bool        runRarely   = false,
                                  bool        insertAtEnd = false);
  
      BasicBlock* fgNewBBinRegion(BBjumpKinds jumpKind,
                                  BasicBlock* srcBlk,
                                  bool        runRarely   = false,
                                  bool        insertAtEnd = false);
  
      BasicBlock* fgNewBBinRegion(BBjumpKinds jumpKind);
  
      BasicBlock* fgNewBBinRegionWorker(BBjumpKinds jumpKind,
                                        BasicBlock* afterBlk,
                                        unsigned    xcptnIndex,
                                        bool        putInTryRegion);
  
      void fgInsertBBbefore(BasicBlock* insertBeforeBlk, BasicBlock* newBlk);
      void fgInsertBBafter(BasicBlock* insertAfterBlk, BasicBlock* newBlk);
      void fgUnlinkBlock(BasicBlock* block);
  
  #ifdef FEATURE_JIT_METHOD_PERF
      unsigned fgMeasureIR();
  #endif // FEATURE_JIT_METHOD_PERF
  
      bool fgModified;             // True if the flow graph has been modified recently
      bool fgComputePredsDone;     // Have we computed the bbPreds list
      bool fgCheapPredsValid;      // Is the bbCheapPreds list valid?
      bool fgDomsComputed;         // Have we computed the dominator sets?
      bool fgReturnBlocksComputed; // Have we computed the return blocks list?
      bool fgOptimizedFinally;     // Did we optimize any try-finallys?
  
      bool fgHasSwitch; // any BBJ_SWITCH jumps?
  
      BlockSet fgEnterBlks; // Set of blocks which have a special transfer of control; the "entry" blocks plus EH handler
                            // begin blocks.
  #if defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
      BlockSet fgAlwaysBlks; // Set of blocks which are BBJ_ALWAYS part  of BBJ_CALLFINALLY/BBJ_ALWAYS pair that should
                             // never be removed due to a requirement to use the BBJ_ALWAYS for generating code and
                             // not have "retless" blocks.
  
  #endif // defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
  
  #ifdef DEBUG
      bool fgReachabilitySetsValid; // Are the bbReach sets valid?
      bool fgEnterBlksSetValid;     // Is the fgEnterBlks set valid?
  #endif                            // DEBUG
  
      bool fgRemoveRestOfBlock; // true if we know that we will throw
      bool fgStmtRemoved;       // true if we remove statements -> need new DFA
  
      // There are two modes for ordering of the trees.
      //  - In FGOrderTree, the dominant ordering is the tree order, and the nodes contained in
      //    each tree and sub-tree are contiguous, and can be traversed (in gtNext/gtPrev order)
      //    by traversing the tree according to the order of the operands.
      //  - In FGOrderLinear, the dominant ordering is the linear order.
  
      enum FlowGraphOrder
      {
          FGOrderTree,
          FGOrderLinear
      };
      FlowGraphOrder fgOrder;
  
      // The following are boolean flags that keep track of the state of internal data structures
  
      bool     fgStmtListThreaded;       // true if the node list is now threaded
      bool     fgCanRelocateEHRegions;   // true if we are allowed to relocate the EH regions
      bool     fgEdgeWeightsComputed;    // true after we have called fgComputeEdgeWeights
      bool     fgHaveValidEdgeWeights;   // true if we were successful in computing all of the edge weights
      bool     fgSlopUsedInEdgeWeights;  // true if their was some slop used when computing the edge weights
      bool     fgRangeUsedInEdgeWeights; // true if some of the edgeWeight are expressed in Min..Max form
      bool     fgNeedsUpdateFlowGraph;   // true if we need to run fgUpdateFlowGraph
      weight_t fgCalledCount;            // count of the number of times this method was called
                                         // This is derived from the profile data
                                         // or is BB_UNITY_WEIGHT when we don't have profile data
  
  #if defined(FEATURE_EH_FUNCLETS)
      bool fgFuncletsCreated; // true if the funclet creation phase has been run
  #endif                      // FEATURE_EH_FUNCLETS
  
      bool fgGlobalMorph; // indicates if we are during the global morphing phase
                          // since fgMorphTree can be called from several places
  
      bool     impBoxTempInUse; // the temp below is valid and available
      unsigned impBoxTemp;      // a temporary that is used for boxing
  
  #ifdef DEBUG
      bool jitFallbackCompile; // Are we doing a fallback compile? That is, have we executed a NO_WAY assert,
                               //   and we are trying to compile again in a "safer", minopts mode?
  #endif
  
  #if defined(DEBUG)
      unsigned impInlinedCodeSize;
      bool     fgPrintInlinedMethods;
  #endif
  
      jitstd::vector<flowList*>* fgPredListSortVector;
  
      //-------------------------------------------------------------------------
  
      void fgInit();
  
      PhaseStatus fgImport();
  
      PhaseStatus fgTransformIndirectCalls();
  
      PhaseStatus fgTransformPatchpoints();
  
      PhaseStatus fgInline();
  
      PhaseStatus fgRemoveEmptyTry();
  
      PhaseStatus fgRemoveEmptyFinally();
  
      PhaseStatus fgMergeFinallyChains();
  
      PhaseStatus fgCloneFinally();
  
      void fgCleanupContinuation(BasicBlock* continuation);
  
  #if defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
  
      PhaseStatus fgUpdateFinallyTargetFlags();
  
      void fgClearAllFinallyTargetBits();
  
      void fgAddFinallyTargetFlags();
  
  #endif // defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
  
      PhaseStatus fgTailMergeThrows();
      void fgTailMergeThrowsFallThroughHelper(BasicBlock* predBlock,
                                              BasicBlock* nonCanonicalBlock,
                                              BasicBlock* canonicalBlock,
                                              flowList*   predEdge);
      void fgTailMergeThrowsJumpToHelper(BasicBlock* predBlock,
                                         BasicBlock* nonCanonicalBlock,
                                         BasicBlock* canonicalBlock,
                                         flowList*   predEdge);
  
      GenTree* fgCheckCallArgUpdate(GenTree* parent, GenTree* child, var_types origType);
  
  #if defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
      // Sometimes we need to defer updating the BBF_FINALLY_TARGET bit. fgNeedToAddFinallyTargetBits signals
      // when this is necessary.
      bool fgNeedToAddFinallyTargetBits;
  #endif // defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
  
      bool fgRetargetBranchesToCanonicalCallFinally(BasicBlock*      block,
                                                    BasicBlock*      handler,
                                                    BlockToBlockMap& continuationMap);
  
      GenTree* fgGetCritSectOfStaticMethod();
  
  #if defined(FEATURE_EH_FUNCLETS)
  
      void fgAddSyncMethodEnterExit();
  
      GenTree* fgCreateMonitorTree(unsigned lvaMonitorBool, unsigned lvaThisVar, BasicBlock* block, bool enter);
  
      void fgConvertSyncReturnToLeave(BasicBlock* block);
  
  #endif // FEATURE_EH_FUNCLETS
  
      void fgAddReversePInvokeEnterExit();
  
      bool fgMoreThanOneReturnBlock();
  
      // The number of separate return points in the method.
      unsigned fgReturnCount;
  
      void fgAddInternal();
  
      enum class FoldResult
      {
          FOLD_DID_NOTHING,
          FOLD_CHANGED_CONTROL_FLOW,
          FOLD_REMOVED_LAST_STMT,
          FOLD_ALTERED_LAST_STMT,
      };
  
      FoldResult fgFoldConditional(BasicBlock* block);
  
      void fgMorphStmts(BasicBlock* block);
      void fgMorphBlocks();
  
      void fgMergeBlockReturn(BasicBlock* block);
  
      bool fgMorphBlockStmt(BasicBlock* block, Statement* stmt DEBUGARG(const char* msg));
  
      void fgSetOptions();
  
  #ifdef DEBUG
      static fgWalkPreFn fgAssertNoQmark;
      void fgPreExpandQmarkChecks(GenTree* expr);
      void        fgPostExpandQmarkChecks();
      static void fgCheckQmarkAllowedForm(GenTree* tree);
  #endif
  
      IL_OFFSET fgFindBlockILOffset(BasicBlock* block);
      void fgFixEntryFlowForOSR();
  
      BasicBlock* fgSplitBlockAtBeginning(BasicBlock* curr);
      BasicBlock* fgSplitBlockAtEnd(BasicBlock* curr);
      BasicBlock* fgSplitBlockAfterStatement(BasicBlock* curr, Statement* stmt);
      BasicBlock* fgSplitBlockAfterNode(BasicBlock* curr, GenTree* node); // for LIR
      BasicBlock* fgSplitEdge(BasicBlock* curr, BasicBlock* succ);
  
      Statement* fgNewStmtFromTree(GenTree* tree, BasicBlock* block, const DebugInfo& di);
      Statement* fgNewStmtFromTree(GenTree* tree);
      Statement* fgNewStmtFromTree(GenTree* tree, BasicBlock* block);
      Statement* fgNewStmtFromTree(GenTree* tree, const DebugInfo& di);
  
      GenTree* fgGetTopLevelQmark(GenTree* expr, GenTree** ppDst = nullptr);
      void fgExpandQmarkForCastInstOf(BasicBlock* block, Statement* stmt);
      void fgExpandQmarkStmt(BasicBlock* block, Statement* stmt);
      void fgExpandQmarkNodes();
  
      // Do "simple lowering."  This functionality is (conceptually) part of "general"
      // lowering that is distributed between fgMorph and the lowering phase of LSRA.
      void fgSimpleLowering();
  
      GenTree* fgInitThisClass();
  
      GenTreeCall* fgGetStaticsCCtorHelper(CORINFO_CLASS_HANDLE cls, CorInfoHelpFunc helper);
  
      GenTreeCall* fgGetSharedCCtor(CORINFO_CLASS_HANDLE cls);
  
      bool backendRequiresLocalVarLifetimes()
      {
          return !opts.MinOpts() || m_pLinearScan->willEnregisterLocalVars();
      }
  
      void fgLocalVarLiveness();
  
      void fgLocalVarLivenessInit();
  
      void fgPerNodeLocalVarLiveness(GenTree* node);
      void fgPerBlockLocalVarLiveness();
  
      VARSET_VALRET_TP fgGetHandlerLiveVars(BasicBlock* block);
  
      void fgLiveVarAnalysis(bool updateInternalOnly = false);
  
      void fgComputeLifeCall(VARSET_TP& life, GenTreeCall* call);
  
      void fgComputeLifeTrackedLocalUse(VARSET_TP& life, LclVarDsc& varDsc, GenTreeLclVarCommon* node);
      bool fgComputeLifeTrackedLocalDef(VARSET_TP&           life,
                                        VARSET_VALARG_TP     keepAliveVars,
                                        LclVarDsc&           varDsc,
                                        GenTreeLclVarCommon* node);
      bool fgComputeLifeUntrackedLocal(VARSET_TP&           life,
                                       VARSET_VALARG_TP     keepAliveVars,
                                       LclVarDsc&           varDsc,
                                       GenTreeLclVarCommon* lclVarNode);
      bool fgComputeLifeLocal(VARSET_TP& life, VARSET_VALARG_TP keepAliveVars, GenTree* lclVarNode);
  
      void fgComputeLife(VARSET_TP&       life,
                         GenTree*         startNode,
                         GenTree*         endNode,
                         VARSET_VALARG_TP volatileVars,
                         bool* pStmtInfoDirty DEBUGARG(bool* treeModf));
  
      void fgComputeLifeLIR(VARSET_TP& life, BasicBlock* block, VARSET_VALARG_TP volatileVars);
  
      bool fgTryRemoveNonLocal(GenTree* node, LIR::Range* blockRange);
  
      void fgRemoveDeadStoreLIR(GenTree* store, BasicBlock* block);
      bool fgRemoveDeadStore(GenTree**        pTree,
                             LclVarDsc*       varDsc,
                             VARSET_VALARG_TP life,
                             bool*            doAgain,
                             bool* pStmtInfoDirty DEBUGARG(bool* treeModf));
  
      void fgInterBlockLocalVarLiveness();
  
      // Blocks: convenience methods for enabling range-based `for` iteration over the function's blocks, e.g.:
      // 1.   for (BasicBlock* const block : compiler->Blocks()) ...
      // 2.   for (BasicBlock* const block : compiler->Blocks(startBlock)) ...
      // 3.   for (BasicBlock* const block : compiler->Blocks(startBlock, endBlock)) ...
      // In case (1), the block list can be empty. In case (2), `startBlock` can be nullptr. In case (3),
      // both `startBlock` and `endBlock` must be non-null.
      //
      BasicBlockSimpleList Blocks() const
      {
          return BasicBlockSimpleList(fgFirstBB);
      }
  
      BasicBlockSimpleList Blocks(BasicBlock* startBlock) const
      {
          return BasicBlockSimpleList(startBlock);
      }
  
      BasicBlockRangeList Blocks(BasicBlock* startBlock, BasicBlock* endBlock) const
      {
          return BasicBlockRangeList(startBlock, endBlock);
      }
  
      // The presence of a partial definition presents some difficulties for SSA: this is both a use of some SSA name
      // of "x", and a def of a new SSA name for "x".  The tree only has one local variable for "x", so it has to choose
      // whether to treat that as the use or def.  It chooses the "use", and thus the old SSA name.  This map allows us
      // to record/recover the "def" SSA number, given the lcl var node for "x" in such a tree.
      typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, unsigned> NodeToUnsignedMap;
      NodeToUnsignedMap* m_opAsgnVarDefSsaNums;
      NodeToUnsignedMap* GetOpAsgnVarDefSsaNums()
      {
          if (m_opAsgnVarDefSsaNums == nullptr)
          {
              m_opAsgnVarDefSsaNums = new (getAllocator()) NodeToUnsignedMap(getAllocator());
          }
          return m_opAsgnVarDefSsaNums;
      }
  
      // This map tracks nodes whose value numbers explicitly or implicitly depend on memory states.
      // The map provides the entry block of the most closely enclosing loop that
      // defines the memory region accessed when defining the nodes's VN.
      //
      // This information should be consulted when considering hoisting node out of a loop, as the VN
      // for the node will only be valid within the indicated loop.
      //
      // It is not fine-grained enough to track memory dependence within loops, so cannot be used
      // for more general code motion.
      //
      // If a node does not have an entry in the map we currently assume the VN is not memory dependent
      // and so memory does not constrain hoisting.
      //
      typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, BasicBlock*> NodeToLoopMemoryBlockMap;
      NodeToLoopMemoryBlockMap* m_nodeToLoopMemoryBlockMap;
      NodeToLoopMemoryBlockMap* GetNodeToLoopMemoryBlockMap()
      {
          if (m_nodeToLoopMemoryBlockMap == nullptr)
          {
              m_nodeToLoopMemoryBlockMap = new (getAllocator()) NodeToLoopMemoryBlockMap(getAllocator());
          }
          return m_nodeToLoopMemoryBlockMap;
      }
  
      void optRecordLoopMemoryDependence(GenTree* tree, BasicBlock* block, ValueNum memoryVN);
      void optCopyLoopMemoryDependence(GenTree* fromTree, GenTree* toTree);
  
      // Requires value numbering phase to have completed. Returns the value number ("gtVN") of the
      // "tree," EXCEPT in the case of GTF_VAR_USEASG, because the tree node's gtVN member is the
      // "use" VN. Performs a lookup into the map of (use asg tree -> def VN.) to return the "def's"
      // VN.
      inline ValueNum GetUseAsgDefVNOrTreeVN(GenTree* tree);
  
      // Requires that "lcl" has the GTF_VAR_DEF flag set.  Returns the SSA number of "lcl".
      // Except: assumes that lcl is a def, and if it is
      // a partial def (GTF_VAR_USEASG), looks up and returns the SSA number for the "def",
      // rather than the "use" SSA number recorded in the tree "lcl".
      inline unsigned GetSsaNumForLocalVarDef(GenTree* lcl);
  
      inline bool PreciseRefCountsRequired();
  
      // Performs SSA conversion.
      void fgSsaBuild();
  
      // Reset any data structures to the state expected by "fgSsaBuild", so it can be run again.
      void fgResetForSsa();
  
      unsigned fgSsaPassesCompleted; // Number of times fgSsaBuild has been run.
  
      // Returns "true" if this is a special variable that is never zero initialized in the prolog.
      inline bool fgVarIsNeverZeroInitializedInProlog(unsigned varNum);
  
      // Returns "true" if the variable needs explicit zero initialization.
      inline bool fgVarNeedsExplicitZeroInit(unsigned varNum, bool bbInALoop, bool bbIsReturn);
  
      // The value numbers for this compilation.
      ValueNumStore* vnStore;
  
  public:
      ValueNumStore* GetValueNumStore()
      {
          return vnStore;
      }
  
      // Do value numbering (assign a value number to each
      // tree node).
      void fgValueNumber();
  
      // Computes new GcHeap VN via the assignment H[elemTypeEq][arrVN][inx][fldSeq] = rhsVN.
      // Assumes that "elemTypeEq" is the (equivalence class rep) of the array element type.
      // The 'indType' is the indirection type of the lhs of the assignment and will typically
      // match the element type of the array or fldSeq.  When this type doesn't match
      // or if the fldSeq is 'NotAField' we invalidate the array contents H[elemTypeEq][arrVN]
      //
      ValueNum fgValueNumberArrIndexAssign(CORINFO_CLASS_HANDLE elemTypeEq,
                                           ValueNum             arrVN,
                                           ValueNum             inxVN,
                                           FieldSeqNode*        fldSeq,
                                           ValueNum             rhsVN,
                                           var_types            indType);
  
      // Requires that "tree" is a GT_IND marked as an array index, and that its address argument
      // has been parsed to yield the other input arguments.  If evaluation of the address
      // can raise exceptions, those should be captured in the exception set "addrXvnp".
      // Assumes that "elemTypeEq" is the (equivalence class rep) of the array element type.
      // Marks "tree" with the VN for H[elemTypeEq][arrVN][inx][fldSeq] (for the liberal VN; a new unique
      // VN for the conservative VN.)  Also marks the tree's argument as the address of an array element.
      // The type tree->TypeGet() will typically match the element type of the array or fldSeq.
      // When this type doesn't match or if the fldSeq is 'NotAField' we return a new unique VN
      //
      ValueNum fgValueNumberArrIndexVal(GenTree*             tree,
                                        CORINFO_CLASS_HANDLE elemTypeEq,
                                        ValueNum             arrVN,
                                        ValueNum             inxVN,
                                        ValueNumPair         addrXvnp,
                                        FieldSeqNode*        fldSeq);
  
      // Requires "funcApp" to be a VNF_PtrToArrElem, and "addrXvnp" to represent the exception set thrown
      // by evaluating the array index expression "tree".  Returns the value number resulting from
      // dereferencing the array in the current GcHeap state.  If "tree" is non-null, it must be the
      // "GT_IND" that does the dereference, and it is given the returned value number.
      ValueNum fgValueNumberArrIndexVal(GenTree* tree, VNFuncApp* funcApp, ValueNumPair addrXvnp);
  
      // Compute the value number for a byref-exposed load of the given type via the given pointerVN.
      ValueNum fgValueNumberByrefExposedLoad(var_types type, ValueNum pointerVN);
  
      unsigned fgVNPassesCompleted; // Number of times fgValueNumber has been run.
  
      // Utility functions for fgValueNumber.
  
      // Perform value-numbering for the trees in "blk".
      void fgValueNumberBlock(BasicBlock* blk);
  
      // Requires that "entryBlock" is the entry block of loop "loopNum", and that "loopNum" is the
      // innermost loop of which "entryBlock" is the entry.  Returns the value number that should be
      // assumed for the memoryKind at the start "entryBlk".
      ValueNum fgMemoryVNForLoopSideEffects(MemoryKind memoryKind, BasicBlock* entryBlock, unsigned loopNum);
  
      // Called when an operation (performed by "tree", described by "msg") may cause the GcHeap to be mutated.
      // As GcHeap is a subset of ByrefExposed, this will also annotate the ByrefExposed mutation.
      void fgMutateGcHeap(GenTree* tree DEBUGARG(const char* msg));
  
      // Called when an operation (performed by "tree", described by "msg") may cause an address-exposed local to be
      // mutated.
      void fgMutateAddressExposedLocal(GenTree* tree DEBUGARG(const char* msg));
  
      // For a GC heap store at curTree, record the new curMemoryVN's and update curTree's MemorySsaMap.
      // As GcHeap is a subset of ByrefExposed, this will also record the ByrefExposed store.
      void recordGcHeapStore(GenTree* curTree, ValueNum gcHeapVN DEBUGARG(const char* msg));
  
      // For a store to an address-exposed local at curTree, record the new curMemoryVN and update curTree's MemorySsaMap.
      void recordAddressExposedLocalStore(GenTree* curTree, ValueNum memoryVN DEBUGARG(const char* msg));
  
      void fgSetCurrentMemoryVN(MemoryKind memoryKind, ValueNum newMemoryVN);
  
      // Tree caused an update in the current memory VN.  If "tree" has an associated heap SSA #, record that
      // value in that SSA #.
      void fgValueNumberRecordMemorySsa(MemoryKind memoryKind, GenTree* tree);
  
      // The input 'tree' is a leaf node that is a constant
      // Assign the proper value number to the tree
      void fgValueNumberTreeConst(GenTree* tree);
  
      // If the VN store has been initialized, reassign the
      // proper value number to the constant tree.
      void fgUpdateConstTreeValueNumber(GenTree* tree);
  
      // Assumes that all inputs to "tree" have had value numbers assigned; assigns a VN to tree.
      // (With some exceptions: the VN of the lhs of an assignment is assigned as part of the
      // assignment.)
      void fgValueNumberTree(GenTree* tree);
  
      void fgValueNumberAssignment(GenTreeOp* tree);
  
      // Does value-numbering for a block assignment.
      void fgValueNumberBlockAssignment(GenTree* tree);
  
      bool fgValueNumberBlockAssignmentTypeCheck(LclVarDsc* dstVarDsc, FieldSeqNode* dstFldSeq, GenTree* src);
  
      // Does value-numbering for a cast tree.
      void fgValueNumberCastTree(GenTree* tree);
  
      // Does value-numbering for an intrinsic tree.
      void fgValueNumberIntrinsic(GenTree* tree);
  
  #ifdef FEATURE_SIMD
      // Does value-numbering for a GT_SIMD tree
      void fgValueNumberSimd(GenTreeSIMD* tree);
  #endif // FEATURE_SIMD
  
  #ifdef FEATURE_HW_INTRINSICS
      // Does value-numbering for a GT_HWINTRINSIC tree
      void fgValueNumberHWIntrinsic(GenTreeHWIntrinsic* tree);
  #endif // FEATURE_HW_INTRINSICS
  
      // Does value-numbering for a call.  We interpret some helper calls.
      void fgValueNumberCall(GenTreeCall* call);
  
      // Does value-numbering for a helper representing a cast operation.
      void fgValueNumberCastHelper(GenTreeCall* call);
  
      // Does value-numbering for a helper "call" that has a VN function symbol "vnf".
      void fgValueNumberHelperCallFunc(GenTreeCall* call, VNFunc vnf, ValueNumPair vnpExc);
  
      // Requires "helpCall" to be a helper call.  Assigns it a value number;
      // we understand the semantics of some of the calls.  Returns "true" if
      // the call may modify the heap (we assume arbitrary memory side effects if so).
      bool fgValueNumberHelperCall(GenTreeCall* helpCall);
  
      // Requires that "helpFunc" is one of the pure Jit Helper methods.
      // Returns the corresponding VNFunc to use for value numbering
      VNFunc fgValueNumberJitHelperMethodVNFunc(CorInfoHelpFunc helpFunc);
  
      // Adds the exception set for the current tree node which has a memory indirection operation
      void fgValueNumberAddExceptionSetForIndirection(GenTree* tree, GenTree* baseAddr);
  
      // Adds the exception sets for the current tree node which is performing a division or modulus operation
      void fgValueNumberAddExceptionSetForDivision(GenTree* tree);
  
      // Adds the exception set for the current tree node which is performing a overflow checking operation
      void fgValueNumberAddExceptionSetForOverflow(GenTree* tree);
  
      // Adds the exception set for the current tree node which is performing a bounds check operation
      void fgValueNumberAddExceptionSetForBoundsCheck(GenTree* tree);
  
      // Adds the exception set for the current tree node which is performing a ckfinite operation
      void fgValueNumberAddExceptionSetForCkFinite(GenTree* tree);
  
      // Adds the exception sets for the current tree node
      void fgValueNumberAddExceptionSet(GenTree* tree);
  
  #ifdef DEBUG
      void fgDebugCheckExceptionSets();
  #endif
  
      // These are the current value number for the memory implicit variables while
      // doing value numbering.  These are the value numbers under the "liberal" interpretation
      // of memory values; the "conservative" interpretation needs no VN, since every access of
      // memory yields an unknown value.
      ValueNum fgCurMemoryVN[MemoryKindCount];
  
      // Return a "pseudo"-class handle for an array element type.  If "elemType" is TYP_STRUCT,
      // requires "elemStructType" to be non-null (and to have a low-order zero).  Otherwise, low order bit
      // is 1, and the rest is an encoding of "elemTyp".
      static CORINFO_CLASS_HANDLE EncodeElemType(var_types elemTyp, CORINFO_CLASS_HANDLE elemStructType)
      {
          if (elemStructType != nullptr)
          {
              assert(varTypeIsStruct(elemTyp) || elemTyp == TYP_REF || elemTyp == TYP_BYREF ||
                     varTypeIsIntegral(elemTyp));
              assert((size_t(elemStructType) & 0x1) == 0x0); // Make sure the encoding below is valid.
              return elemStructType;
          }
          else
          {
              assert(elemTyp != TYP_STRUCT);
              elemTyp = varTypeToSigned(elemTyp);
              return CORINFO_CLASS_HANDLE(size_t(elemTyp) << 1 | 0x1);
          }
      }
      // If "clsHnd" is the result of an "EncodePrim" call, returns true and sets "*pPrimType" to the
      // var_types it represents.  Otherwise, returns TYP_STRUCT (on the assumption that "clsHnd" is
      // the struct type of the element).
      static var_types DecodeElemType(CORINFO_CLASS_HANDLE clsHnd)
      {
          size_t clsHndVal = size_t(clsHnd);
          if (clsHndVal & 0x1)
          {
              return var_types(clsHndVal >> 1);
          }
          else
          {
              return TYP_STRUCT;
          }
      }
  
      // Convert a BYTE which represents the VM's CorInfoGCtype to the JIT's var_types
      var_types getJitGCType(BYTE gcType);
  
      // Returns true if the provided type should be treated as a primitive type
      // for the unmanaged calling conventions.
      bool isNativePrimitiveStructType(CORINFO_CLASS_HANDLE clsHnd);
  
      enum structPassingKind
      {
          SPK_Unknown,       // Invalid value, never returned
          SPK_PrimitiveType, // The struct is passed/returned using a primitive type.
          SPK_EnclosingType, // Like SPK_Primitive type, but used for return types that
                             //  require a primitive type temp that is larger than the struct size.
                             //  Currently used for structs of size 3, 5, 6, or 7 bytes.
          SPK_ByValue,       // The struct is passed/returned by value (using the ABI rules)
                             //  for ARM64 and UNIX_X64 in multiple registers. (when all of the
                             //   parameters registers are used, then the stack will be used)
                             //  for X86 passed on the stack, for ARM32 passed in registers
                             //   or the stack or split between registers and the stack.
          SPK_ByValueAsHfa,  // The struct is passed/returned as an HFA in multiple registers.
          SPK_ByReference
      }; // The struct is passed/returned by reference to a copy/buffer.
  
      // Get the "primitive" type that is is used when we are given a struct of size 'structSize'.
      // For pointer sized structs the 'clsHnd' is used to determine if the struct contains GC ref.
      // A "primitive" type is one of the scalar types: byte, short, int, long, ref, float, double
      // If we can't or shouldn't use a "primitive" type then TYP_UNKNOWN is returned.
      //
      // isVarArg is passed for use on Windows Arm64 to change the decision returned regarding
      // hfa types.
      //
      var_types getPrimitiveTypeForStruct(unsigned structSize, CORINFO_CLASS_HANDLE clsHnd, bool isVarArg);
  
      // Get the type that is used to pass values of the given struct type.
      // isVarArg is passed for use on Windows Arm64 to change the decision returned regarding
      // hfa types.
      //
      var_types getArgTypeForStruct(CORINFO_CLASS_HANDLE clsHnd,
                                    structPassingKind*   wbPassStruct,
                                    bool                 isVarArg,
                                    unsigned             structSize);
  
      // Get the type that is used to return values of the given struct type.
      // If the size is unknown, pass 0 and it will be determined from 'clsHnd'.
      var_types getReturnTypeForStruct(CORINFO_CLASS_HANDLE     clsHnd,
                                       CorInfoCallConvExtension callConv,
                                       structPassingKind*       wbPassStruct = nullptr,
                                       unsigned                 structSize   = 0);
  
  #ifdef DEBUG
      // Print a representation of "vnp" or "vn" on standard output.
      // If "level" is non-zero, we also print out a partial expansion of the value.
      void vnpPrint(ValueNumPair vnp, unsigned level);
      void vnPrint(ValueNum vn, unsigned level);
  #endif
  
      bool fgDominate(BasicBlock* b1, BasicBlock* b2); // Return true if b1 dominates b2
  
      // Dominator computation member functions
      // Not exposed outside Compiler
  protected:
      bool fgReachable(BasicBlock* b1, BasicBlock* b2); // Returns true if block b1 can reach block b2
  
      // Compute immediate dominators, the dominator tree and and its pre/post-order travsersal numbers.
      void fgComputeDoms();
  
      void fgCompDominatedByExceptionalEntryBlocks();
  
      BlockSet_ValRet_T fgGetDominatorSet(BasicBlock* block); // Returns a set of blocks that dominate the given block.
      // Note: this is relatively slow compared to calling fgDominate(),
      // especially if dealing with a single block versus block check.
  
      void fgComputeReachabilitySets(); // Compute bbReach sets. (Also sets BBF_GC_SAFE_POINT flag on blocks.)
  
      void fgComputeReturnBlocks(); // Initialize fgReturnBlocks to a list of BBJ_RETURN blocks.
  
      void fgComputeEnterBlocksSet(); // Compute the set of entry blocks, 'fgEnterBlks'.
  
      bool fgRemoveUnreachableBlocks(); // Remove blocks determined to be unreachable by the bbReach sets.
  
      void fgComputeReachability(); // Perform flow graph node reachability analysis.
  
      BasicBlock* fgIntersectDom(BasicBlock* a, BasicBlock* b); // Intersect two immediate dominator sets.
  
      void fgDfsInvPostOrder(); // In order to compute dominance using fgIntersectDom, the flow graph nodes must be
                                // processed in topological sort, this function takes care of that.
  
      void fgDfsInvPostOrderHelper(BasicBlock* block, BlockSet& visited, unsigned* count);
  
      BlockSet_ValRet_T fgDomFindStartNodes(); // Computes which basic blocks don't have incoming edges in the flow graph.
                                               // Returns this as a set.
  
      INDEBUG(void fgDispDomTree(DomTreeNode* domTree);) // Helper that prints out the Dominator Tree in debug builds.
  
      DomTreeNode* fgBuildDomTree(); // Once we compute all the immediate dominator sets for each node in the flow graph
                                     // (performed by fgComputeDoms), this procedure builds the dominance tree represented
                                     // adjacency lists.
  
      // In order to speed up the queries of the form 'Does A dominates B', we can perform a DFS preorder and postorder
      // traversal of the dominance tree and the dominance query will become A dominates B iif preOrder(A) <= preOrder(B)
      // && postOrder(A) >= postOrder(B) making the computation O(1).
      void fgNumberDomTree(DomTreeNode* domTree);
  
      // When the flow graph changes, we need to update the block numbers, predecessor lists, reachability sets,
      // dominators, and possibly loops.
      void fgUpdateChangedFlowGraph(const bool computePreds        = true,
                                    const bool computeDoms         = true,
                                    const bool computeReturnBlocks = false,
                                    const bool computeLoops        = false);
  
  public:
      // Compute the predecessors of the blocks in the control flow graph.
      void fgComputePreds();
  
      // Remove all predecessor information.
      void fgRemovePreds();
  
      // Compute the cheap flow graph predecessors lists. This is used in some early phases
      // before the full predecessors lists are computed.
      void fgComputeCheapPreds();
  
  private:
      void fgAddCheapPred(BasicBlock* block, BasicBlock* blockPred);
  
      void fgRemoveCheapPred(BasicBlock* block, BasicBlock* blockPred);
  
  public:
      enum GCPollType
      {
          GCPOLL_NONE,
          GCPOLL_CALL,
          GCPOLL_INLINE
      };
  
      // Initialize the per-block variable sets (used for liveness analysis).
      void fgInitBlockVarSets();
  
      PhaseStatus fgInsertGCPolls();
      BasicBlock* fgCreateGCPoll(GCPollType pollType, BasicBlock* block);
  
      // Requires that "block" is a block that returns from
      // a finally.  Returns the number of successors (jump targets of
      // of blocks in the covered "try" that did a "LEAVE".)
      unsigned fgNSuccsOfFinallyRet(BasicBlock* block);
  
      // Requires that "block" is a block that returns (in the sense of BBJ_EHFINALLYRET) from
      // a finally.  Returns its "i"th successor (jump targets of
      // of blocks in the covered "try" that did a "LEAVE".)
      // Requires that "i" < fgNSuccsOfFinallyRet(block).
      BasicBlock* fgSuccOfFinallyRet(BasicBlock* block, unsigned i);
  
  private:
      // Factor out common portions of the impls of the methods above.
      void fgSuccOfFinallyRetWork(BasicBlock* block, unsigned i, BasicBlock** bres, unsigned* nres);
  
  public:
      // For many purposes, it is desirable to be able to enumerate the *distinct* targets of a switch statement,
      // skipping duplicate targets.  (E.g., in flow analyses that are only interested in the set of possible targets.)
      // SwitchUniqueSuccSet contains the non-duplicated switch targets.
      // (Code that modifies the jump table of a switch has an obligation to call Compiler::UpdateSwitchTableTarget,
      // which in turn will call the "UpdateTarget" method of this type if a SwitchUniqueSuccSet has already
      // been computed for the switch block.  If a switch block is deleted or is transformed into a non-switch,
      // we leave the entry associated with the block, but it will no longer be accessed.)
      struct SwitchUniqueSuccSet
      {
          unsigned     numDistinctSuccs; // Number of distinct targets of the switch.
          BasicBlock** nonDuplicates;    // Array of "numDistinctSuccs", containing all the distinct switch target
                                         // successors.
  
          // The switch block "switchBlk" just had an entry with value "from" modified to the value "to".
          // Update "this" as necessary: if "from" is no longer an element of the jump table of "switchBlk",
          // remove it from "this", and ensure that "to" is a member.  Use "alloc" to do any required allocation.
          void UpdateTarget(CompAllocator alloc, BasicBlock* switchBlk, BasicBlock* from, BasicBlock* to);
      };
  
      typedef JitHashTable<BasicBlock*, JitPtrKeyFuncs<BasicBlock>, SwitchUniqueSuccSet> BlockToSwitchDescMap;
  
  private:
      // Maps BasicBlock*'s that end in switch statements to SwitchUniqueSuccSets that allow
      // iteration over only the distinct successors.
      BlockToSwitchDescMap* m_switchDescMap;
  
  public:
      BlockToSwitchDescMap* GetSwitchDescMap(bool createIfNull = true)
      {
          if ((m_switchDescMap == nullptr) && createIfNull)
          {
              m_switchDescMap = new (getAllocator()) BlockToSwitchDescMap(getAllocator());
          }
          return m_switchDescMap;
      }
  
      // Invalidate the map of unique switch block successors. For example, since the hash key of the map
      // depends on block numbers, we must invalidate the map when the blocks are renumbered, to ensure that
      // we don't accidentally look up and return the wrong switch data.
      void InvalidateUniqueSwitchSuccMap()
      {
          m_switchDescMap = nullptr;
      }
  
      // Requires "switchBlock" to be a block that ends in a switch.  Returns
      // the corresponding SwitchUniqueSuccSet.
      SwitchUniqueSuccSet GetDescriptorForSwitch(BasicBlock* switchBlk);
  
      // The switch block "switchBlk" just had an entry with value "from" modified to the value "to".
      // Update "this" as necessary: if "from" is no longer an element of the jump table of "switchBlk",
      // remove it from "this", and ensure that "to" is a member.
      void UpdateSwitchTableTarget(BasicBlock* switchBlk, BasicBlock* from, BasicBlock* to);
  
      // Remove the "SwitchUniqueSuccSet" of "switchBlk" in the BlockToSwitchDescMap.
      void fgInvalidateSwitchDescMapEntry(BasicBlock* switchBlk);
  
      BasicBlock* fgFirstBlockOfHandler(BasicBlock* block);
  
      bool fgIsFirstBlockOfFilterOrHandler(BasicBlock* block);
  
      flowList* fgGetPredForBlock(BasicBlock* block, BasicBlock* blockPred);
  
      flowList* fgGetPredForBlock(BasicBlock* block, BasicBlock* blockPred, flowList*** ptrToPred);
  
      flowList* fgRemoveRefPred(BasicBlock* block, BasicBlock* blockPred);
  
      flowList* fgRemoveAllRefPreds(BasicBlock* block, BasicBlock* blockPred);
  
      void fgRemoveBlockAsPred(BasicBlock* block);
  
      void fgChangeSwitchBlock(BasicBlock* oldSwitchBlock, BasicBlock* newSwitchBlock);
  
      void fgReplaceSwitchJumpTarget(BasicBlock* blockSwitch, BasicBlock* newTarget, BasicBlock* oldTarget);
  
      void fgReplaceJumpTarget(BasicBlock* block, BasicBlock* newTarget, BasicBlock* oldTarget);
  
      void fgReplacePred(BasicBlock* block, BasicBlock* oldPred, BasicBlock* newPred);
  
      flowList* fgAddRefPred(BasicBlock* block,
                             BasicBlock* blockPred,
                             flowList*   oldEdge           = nullptr,
                             bool        initializingPreds = false); // Only set to 'true' when we are computing preds in
                                                                     // fgComputePreds()
  
      void fgFindBasicBlocks();
  
      bool fgIsBetterFallThrough(BasicBlock* bCur, BasicBlock* bAlt);
  
      bool fgCheckEHCanInsertAfterBlock(BasicBlock* blk, unsigned regionIndex, bool putInTryRegion);
  
      BasicBlock* fgFindInsertPoint(unsigned    regionIndex,
                                    bool        putInTryRegion,
                                    BasicBlock* startBlk,
                                    BasicBlock* endBlk,
                                    BasicBlock* nearBlk,
                                    BasicBlock* jumpBlk,
                                    bool        runRarely);
  
      unsigned fgGetNestingLevel(BasicBlock* block, unsigned* pFinallyNesting = nullptr);
  
      void fgPostImportationCleanup();
  
      void fgRemoveStmt(BasicBlock* block, Statement* stmt DEBUGARG(bool isUnlink = false));
      void fgUnlinkStmt(BasicBlock* block, Statement* stmt);
  
      bool fgCheckRemoveStmt(BasicBlock* block, Statement* stmt);
  
      void fgCreateLoopPreHeader(unsigned lnum);
  
      void fgUnreachableBlock(BasicBlock* block);
  
      void fgRemoveConditionalJump(BasicBlock* block);
  
      BasicBlock* fgLastBBInMainFunction();
  
      BasicBlock* fgEndBBAfterMainFunction();
  
      void fgUnlinkRange(BasicBlock* bBeg, BasicBlock* bEnd);
  
      void fgRemoveBlock(BasicBlock* block, bool unreachable);
  
      bool fgCanCompactBlocks(BasicBlock* block, BasicBlock* bNext);
  
      void fgCompactBlocks(BasicBlock* block, BasicBlock* bNext);
  
      void fgUpdateLoopsAfterCompacting(BasicBlock* block, BasicBlock* bNext);
  
      BasicBlock* fgConnectFallThrough(BasicBlock* bSrc, BasicBlock* bDst);
  
      bool fgRenumberBlocks();
  
      bool fgExpandRarelyRunBlocks();
  
      bool fgEhAllowsMoveBlock(BasicBlock* bBefore, BasicBlock* bAfter);
  
      void fgMoveBlocksAfter(BasicBlock* bStart, BasicBlock* bEnd, BasicBlock* insertAfterBlk);
  
      enum FG_RELOCATE_TYPE
      {
          FG_RELOCATE_TRY,    // relocate the 'try' region
          FG_RELOCATE_HANDLER // relocate the handler region (including the filter if necessary)
      };
      BasicBlock* fgRelocateEHRange(unsigned regionIndex, FG_RELOCATE_TYPE relocateType);
  
  #if defined(FEATURE_EH_FUNCLETS)
  #if defined(TARGET_ARM)
      void fgClearFinallyTargetBit(BasicBlock* block);
  #endif // defined(TARGET_ARM)
      bool fgIsIntraHandlerPred(BasicBlock* predBlock, BasicBlock* block);
      bool fgAnyIntraHandlerPreds(BasicBlock* block);
      void fgInsertFuncletPrologBlock(BasicBlock* block);
      void fgCreateFuncletPrologBlocks();
      void fgCreateFunclets();
  #else  // !FEATURE_EH_FUNCLETS
      bool fgRelocateEHRegions();
  #endif // !FEATURE_EH_FUNCLETS
  
      bool fgOptimizeUncondBranchToSimpleCond(BasicBlock* block, BasicBlock* target);
  
      bool fgBlockEndFavorsTailDuplication(BasicBlock* block, unsigned lclNum);
  
      bool fgBlockIsGoodTailDuplicationCandidate(BasicBlock* block, unsigned* lclNum);
  
      bool fgOptimizeEmptyBlock(BasicBlock* block);
  
      bool fgOptimizeBranchToEmptyUnconditional(BasicBlock* block, BasicBlock* bDest);
  
      bool fgOptimizeBranch(BasicBlock* bJump);
  
      bool fgOptimizeSwitchBranches(BasicBlock* block);
  
      bool fgOptimizeBranchToNext(BasicBlock* block, BasicBlock* bNext, BasicBlock* bPrev);
  
      bool fgOptimizeSwitchJumps();
  #ifdef DEBUG
      void fgPrintEdgeWeights();
  #endif
      void     fgComputeBlockAndEdgeWeights();
      weight_t fgComputeMissingBlockWeights();
      void fgComputeCalledCount(weight_t returnWeight);
      void fgComputeEdgeWeights();
  
      bool fgReorderBlocks();
  
      PhaseStatus fgDetermineFirstColdBlock();
  
      bool fgIsForwardBranch(BasicBlock* bJump, BasicBlock* bSrc = nullptr);
  
      bool fgUpdateFlowGraph(bool doTailDup = false);
  
      void fgFindOperOrder();
  
      // method that returns if you should split here
      typedef bool(fgSplitPredicate)(GenTree* tree, GenTree* parent, fgWalkData* data);
  
      void fgSetBlockOrder();
  
      void fgRemoveReturnBlock(BasicBlock* block);
  
      /* Helper code that has been factored out */
      inline void fgConvertBBToThrowBB(BasicBlock* block);
  
      bool fgCastNeeded(GenTree* tree, var_types toType);
      GenTree* fgDoNormalizeOnStore(GenTree* tree);
      GenTree* fgMakeTmpArgNode(fgArgTabEntry* curArgTabEntry);
  
      // The following check for loops that don't execute calls
      bool fgLoopCallMarked;
  
      void fgLoopCallTest(BasicBlock* srcBB, BasicBlock* dstBB);
      void fgLoopCallMark();
  
      void fgMarkLoopHead(BasicBlock* block);
  
      unsigned fgGetCodeEstimate(BasicBlock* block);
  
  #if DUMP_FLOWGRAPHS
      enum class PhasePosition
      {
          PrePhase,
          PostPhase
      };
      const char* fgProcessEscapes(const char* nameIn, escapeMapping_t* map);
      static void fgDumpTree(FILE* fgxFile, GenTree* const tree);
      FILE* fgOpenFlowGraphFile(bool* wbDontClose, Phases phase, PhasePosition pos, LPCWSTR type);
      bool fgDumpFlowGraph(Phases phase, PhasePosition pos);
  #endif // DUMP_FLOWGRAPHS
  
  #ifdef DEBUG
  
      void fgDispDoms();
      void fgDispReach();
      void fgDispBBLiveness(BasicBlock* block);
      void fgDispBBLiveness();
      void fgTableDispBasicBlock(BasicBlock* block, int ibcColWidth = 0);
      void fgDispBasicBlocks(BasicBlock* firstBlock, BasicBlock* lastBlock, bool dumpTrees);
      void fgDispBasicBlocks(bool dumpTrees = false);
      void fgDumpStmtTree(Statement* stmt, unsigned bbNum);
      void fgDumpBlock(BasicBlock* block);
      void fgDumpTrees(BasicBlock* firstBlock, BasicBlock* lastBlock);
  
      static fgWalkPreFn fgStress64RsltMulCB;
      void               fgStress64RsltMul();
      void               fgDebugCheckUpdate();
  
      void fgDebugCheckBBNumIncreasing();
      void fgDebugCheckBBlist(bool checkBBNum = false, bool checkBBRefs = true);
      void fgDebugCheckBlockLinks();
      void fgDebugCheckLinks(bool morphTrees = false);
      void fgDebugCheckStmtsList(BasicBlock* block, bool morphTrees);
      void fgDebugCheckNodeLinks(BasicBlock* block, Statement* stmt);
      void fgDebugCheckNodesUniqueness();
      void fgDebugCheckLoopTable();
  
      void fgDebugCheckFlags(GenTree* tree);
      void fgDebugCheckDispFlags(GenTree* tree, GenTreeFlags dispFlags, GenTreeDebugFlags debugFlags);
      void fgDebugCheckFlagsHelper(GenTree* tree, GenTreeFlags actualFlags, GenTreeFlags expectedFlags);
      void fgDebugCheckTryFinallyExits();
      void fgDebugCheckProfileData();
      bool fgDebugCheckIncomingProfileData(BasicBlock* block);
      bool fgDebugCheckOutgoingProfileData(BasicBlock* block);
  
  #endif // DEBUG
  
      static bool fgProfileWeightsEqual(weight_t weight1, weight_t weight2);
      static bool fgProfileWeightsConsistent(weight_t weight1, weight_t weight2);
  
      static GenTree* fgGetFirstNode(GenTree* tree);
  
      //--------------------- Walking the trees in the IR -----------------------
  
      struct fgWalkData
      {
          Compiler*     compiler;
          fgWalkPreFn*  wtprVisitorFn;
          fgWalkPostFn* wtpoVisitorFn;
          void*         pCallbackData; // user-provided data
          GenTree*      parent;        // parent of current node, provided to callback
          GenTreeStack* parentStack;   // stack of parent nodes, if asked for
          bool          wtprLclsOnly;  // whether to only visit lclvar nodes
  #ifdef DEBUG
          bool printModified; // callback can use this
  #endif
      };
  
      fgWalkResult fgWalkTreePre(GenTree**    pTree,
                                 fgWalkPreFn* visitor,
                                 void*        pCallBackData = nullptr,
                                 bool         lclVarsOnly   = false,
                                 bool         computeStack  = false);
  
      fgWalkResult fgWalkTree(GenTree**     pTree,
                              fgWalkPreFn*  preVisitor,
                              fgWalkPostFn* postVisitor,
                              void*         pCallBackData = nullptr);
  
      void fgWalkAllTreesPre(fgWalkPreFn* visitor, void* pCallBackData);
  
      //----- Postorder
  
      fgWalkResult fgWalkTreePost(GenTree**     pTree,
                                  fgWalkPostFn* visitor,
                                  void*         pCallBackData = nullptr,
                                  bool          computeStack  = false);
  
      // An fgWalkPreFn that looks for expressions that have inline throws in
      // minopts mode. Basically it looks for tress with gtOverflowEx() or
      // GTF_IND_RNGCHK.  It returns WALK_ABORT if one is found.  It
      // returns WALK_SKIP_SUBTREES if GTF_EXCEPT is not set (assumes flags
      // properly propagated to parent trees).  It returns WALK_CONTINUE
      // otherwise.
      static fgWalkResult fgChkThrowCB(GenTree** pTree, Compiler::fgWalkData* data);
      static fgWalkResult fgChkLocAllocCB(GenTree** pTree, Compiler::fgWalkData* data);
      static fgWalkResult fgChkQmarkCB(GenTree** pTree, Compiler::fgWalkData* data);
  
      /**************************************************************************
       *                          PROTECTED
       *************************************************************************/
  
  protected:
      friend class SsaBuilder;
      friend struct ValueNumberState;
  
      //--------------------- Detect the basic blocks ---------------------------
  
      BasicBlock** fgBBs; // Table of pointers to the BBs
  
      void        fgInitBBLookup();
      BasicBlock* fgLookupBB(unsigned addr);
  
      bool fgCanSwitchToOptimized();
      void fgSwitchToOptimized(const char* reason);
  
      bool fgMayExplicitTailCall();
  
      void fgFindJumpTargets(const BYTE* codeAddr, IL_OFFSET codeSize, FixedBitVect* jumpTarget);
  
      void fgMarkBackwardJump(BasicBlock* startBlock, BasicBlock* endBlock);
  
      void fgLinkBasicBlocks();
  
      unsigned fgMakeBasicBlocks(const BYTE* codeAddr, IL_OFFSET codeSize, FixedBitVect* jumpTarget);
  
      void fgCheckBasicBlockControlFlow();
  
      void fgControlFlowPermitted(BasicBlock* blkSrc,
                                  BasicBlock* blkDest,
                                  bool        IsLeave = false /* is the src a leave block */);
  
      bool fgFlowToFirstBlockOfInnerTry(BasicBlock* blkSrc, BasicBlock* blkDest, bool sibling);
  
      void fgObserveInlineConstants(OPCODE opcode, const FgStack& stack, bool isInlining);
  
      void fgAdjustForAddressExposedOrWrittenThis();
  
      unsigned fgStressBBProf()
      {
  #ifdef DEBUG
          unsigned result = JitConfig.JitStressBBProf();
          if (result == 0)
          {
              if (compStressCompile(STRESS_BB_PROFILE, 15))
              {
                  result = 1;
              }
          }
          return result;
  #else
          return 0;
  #endif
      }
  
      bool fgHaveProfileData();
      bool fgGetProfileWeightForBasicBlock(IL_OFFSET offset, weight_t* weight);
  
      Instrumentor* fgCountInstrumentor;
      Instrumentor* fgClassInstrumentor;
  
      PhaseStatus fgPrepareToInstrumentMethod();
      PhaseStatus fgInstrumentMethod();
      PhaseStatus fgIncorporateProfileData();
      void        fgIncorporateBlockCounts();
      void        fgIncorporateEdgeCounts();
  
      CORINFO_CLASS_HANDLE getRandomClass(ICorJitInfo::PgoInstrumentationSchema* schema,
                                          UINT32                                 countSchemaItems,
                                          BYTE*                                  pInstrumentationData,
                                          int32_t                                ilOffset,
                                          CLRRandom*                             random);
  
  public:
      const char*                            fgPgoFailReason;
      bool                                   fgPgoDisabled;
      ICorJitInfo::PgoSource                 fgPgoSource;
      ICorJitInfo::PgoInstrumentationSchema* fgPgoSchema;
      BYTE*                                  fgPgoData;
      UINT32                                 fgPgoSchemaCount;
      HRESULT                                fgPgoQueryResult;
      UINT32                                 fgNumProfileRuns;
      UINT32                                 fgPgoBlockCounts;
      UINT32                                 fgPgoEdgeCounts;
      UINT32                                 fgPgoClassProfiles;
      unsigned                               fgPgoInlineePgo;
      unsigned                               fgPgoInlineeNoPgo;
      unsigned                               fgPgoInlineeNoPgoSingleBlock;
  
      void WalkSpanningTree(SpanningTreeVisitor* visitor);
      void fgSetProfileWeight(BasicBlock* block, weight_t weight);
      void fgApplyProfileScale();
      bool fgHaveSufficientProfileData();
      bool fgHaveTrustedProfileData();
  
      // fgIsUsingProfileWeights - returns true if we have real profile data for this method
      //                           or if we have some fake profile data for the stress mode
      bool fgIsUsingProfileWeights()
      {
          return (fgHaveProfileData() || fgStressBBProf());
      }
  
      // fgProfileRunsCount - returns total number of scenario runs for the profile data
      //                      or BB_UNITY_WEIGHT_UNSIGNED when we aren't using profile data.
      unsigned fgProfileRunsCount()
      {
          return fgIsUsingProfileWeights() ? fgNumProfileRuns : BB_UNITY_WEIGHT_UNSIGNED;
      }
  
  //-------- Insert a statement at the start or end of a basic block --------
  
  #ifdef DEBUG
  public:
      static bool fgBlockContainsStatementBounded(BasicBlock* block, Statement* stmt, bool answerOnBoundExceeded = true);
  #endif
  
  public:
      Statement* fgNewStmtAtBeg(BasicBlock* block, GenTree* tree, const DebugInfo& di = DebugInfo());
      void fgInsertStmtAtEnd(BasicBlock* block, Statement* stmt);
      Statement* fgNewStmtAtEnd(BasicBlock* block, GenTree* tree, const DebugInfo& di = DebugInfo());
      Statement* fgNewStmtNearEnd(BasicBlock* block, GenTree* tree, const DebugInfo& di = DebugInfo());
  
  private:
      void fgInsertStmtNearEnd(BasicBlock* block, Statement* stmt);
      void fgInsertStmtAtBeg(BasicBlock* block, Statement* stmt);
      void fgInsertStmtAfter(BasicBlock* block, Statement* insertionPoint, Statement* stmt);
  
  public:
      void fgInsertStmtBefore(BasicBlock* block, Statement* insertionPoint, Statement* stmt);
  
  private:
      Statement* fgInsertStmtListAfter(BasicBlock* block, Statement* stmtAfter, Statement* stmtList);
  
      //                  Create a new temporary variable to hold the result of *ppTree,
      //                  and transform the graph accordingly.
      GenTree* fgInsertCommaFormTemp(GenTree** ppTree, CORINFO_CLASS_HANDLE structType = nullptr);
      GenTree* fgMakeMultiUse(GenTree** ppTree);
  
  private:
      //                  Recognize a bitwise rotation pattern and convert into a GT_ROL or a GT_ROR node.
      GenTree* fgRecognizeAndMorphBitwiseRotation(GenTree* tree);
      bool fgOperIsBitwiseRotationRoot(genTreeOps oper);
  
  #if !defined(TARGET_64BIT)
      //                  Recognize and morph a long multiplication with 32 bit operands.
      GenTreeOp* fgRecognizeAndMorphLongMul(GenTreeOp* mul);
      GenTreeOp* fgMorphLongMul(GenTreeOp* mul);
  #endif
  
      //-------- Determine the order in which the trees will be evaluated -------
  
      unsigned fgTreeSeqNum;
      GenTree* fgTreeSeqLst;
      GenTree* fgTreeSeqBeg;
  
      GenTree* fgSetTreeSeq(GenTree* tree, GenTree* prev = nullptr, bool isLIR = false);
      void fgSetTreeSeqHelper(GenTree* tree, bool isLIR);
      void fgSetTreeSeqFinish(GenTree* tree, bool isLIR);
      void fgSetStmtSeq(Statement* stmt);
      void fgSetBlockOrder(BasicBlock* block);
  
      //------------------------- Morphing --------------------------------------
  
      unsigned fgPtrArgCntMax;
  
  public:
      //------------------------------------------------------------------------
      // fgGetPtrArgCntMax: Return the maximum number of pointer-sized stack arguments that calls inside this method
      // can push on the stack. This value is calculated during morph.
      //
      // Return Value:
      //    Returns fgPtrArgCntMax, that is a private field.
      //
      unsigned fgGetPtrArgCntMax() const
      {
          return fgPtrArgCntMax;
      }
  
      //------------------------------------------------------------------------
      // fgSetPtrArgCntMax: Set the maximum number of pointer-sized stack arguments that calls inside this method
      // can push on the stack. This function is used during StackLevelSetter to fix incorrect morph calculations.
      //
      void fgSetPtrArgCntMax(unsigned argCntMax)
      {
          fgPtrArgCntMax = argCntMax;
      }
  
      bool compCanEncodePtrArgCntMax();
  
  private:
      hashBv* fgOutgoingArgTemps;
      hashBv* fgCurrentlyInUseArgTemps;
  
      void fgSetRngChkTarget(GenTree* tree, bool delay = true);
  
      BasicBlock* fgSetRngChkTargetInner(SpecialCodeKind kind, bool delay);
  
  #if REARRANGE_ADDS
      void fgMoveOpsLeft(GenTree* tree);
  #endif
  
      bool fgIsCommaThrow(GenTree* tree, bool forFolding = false);
  
      bool fgIsThrow(GenTree* tree);
  
      bool fgInDifferentRegions(BasicBlock* blk1, BasicBlock* blk2);
      bool fgIsBlockCold(BasicBlock* block);
  
      GenTree* fgMorphCastIntoHelper(GenTree* tree, int helper, GenTree* oper);
  
      GenTree* fgMorphIntoHelperCall(GenTree* tree, int helper, GenTreeCall::Use* args, bool morphArgs = true);
  
      GenTree* fgMorphStackArgForVarArgs(unsigned lclNum, var_types varType, unsigned lclOffs);
  
      // A "MorphAddrContext" carries information from the surrounding context.  If we are evaluating a byref address,
      // it is useful to know whether the address will be immediately dereferenced, or whether the address value will
      // be used, perhaps by passing it as an argument to a called method.  This affects how null checking is done:
      // for sufficiently small offsets, we can rely on OS page protection to implicitly null-check addresses that we
      // know will be dereferenced.  To know that reliance on implicit null checking is sound, we must further know that
      // all offsets between the top-level indirection and the bottom are constant, and that their sum is sufficiently
      // small; hence the other fields of MorphAddrContext.
      enum MorphAddrContextKind
      {
          MACK_Ind,
          MACK_Addr,
      };
      struct MorphAddrContext
      {
          MorphAddrContextKind m_kind;
          bool                 m_allConstantOffsets; // Valid only for "m_kind == MACK_Ind".  True iff all offsets between
                                                     // top-level indirection and here have been constants.
          size_t m_totalOffset; // Valid only for "m_kind == MACK_Ind", and if "m_allConstantOffsets" is true.
                                // In that case, is the sum of those constant offsets.
  
          MorphAddrContext(MorphAddrContextKind kind) : m_kind(kind), m_allConstantOffsets(true), m_totalOffset(0)
          {
          }
      };
  
      // A MACK_CopyBlock context is immutable, so we can just make one of these and share it.
      static MorphAddrContext s_CopyBlockMAC;
  
  #ifdef FEATURE_SIMD
      GenTree* getSIMDStructFromField(GenTree*     tree,
                                      CorInfoType* simdBaseJitTypeOut,
                                      unsigned*    indexOut,
                                      unsigned*    simdSizeOut,
                                      bool         ignoreUsedInSIMDIntrinsic = false);
      GenTree* fgMorphFieldAssignToSimdSetElement(GenTree* tree);
      GenTree* fgMorphFieldToSimdGetElement(GenTree* tree);
      bool fgMorphCombineSIMDFieldAssignments(BasicBlock* block, Statement* stmt);
      void impMarkContiguousSIMDFieldAssignments(Statement* stmt);
  
      // fgPreviousCandidateSIMDFieldAsgStmt is only used for tracking previous simd field assignment
      // in function: Complier::impMarkContiguousSIMDFieldAssignments.
      Statement* fgPreviousCandidateSIMDFieldAsgStmt;
  
  #endif // FEATURE_SIMD
      GenTree* fgMorphArrayIndex(GenTree* tree);
      GenTree* fgMorphExpandCast(GenTreeCast* tree);
      GenTreeFieldList* fgMorphLclArgToFieldlist(GenTreeLclVarCommon* lcl);
      void fgInitArgInfo(GenTreeCall* call);
      GenTreeCall* fgMorphArgs(GenTreeCall* call);
  
      void fgMakeOutgoingStructArgCopy(GenTreeCall* call, GenTreeCall::Use* args, CORINFO_CLASS_HANDLE copyBlkClass);
  
      GenTree* fgMorphLocalVar(GenTree* tree, bool forceRemorph);
  
  public:
      bool fgAddrCouldBeNull(GenTree* addr);
  
  private:
      GenTree* fgMorphField(GenTree* tree, MorphAddrContext* mac);
      bool fgCanFastTailCall(GenTreeCall* call, const char** failReason);
  #if FEATURE_FASTTAILCALL
      bool fgCallHasMustCopyByrefParameter(GenTreeCall* callee);
  #endif
      bool     fgCheckStmtAfterTailCall();
      GenTree* fgMorphTailCallViaHelpers(GenTreeCall* call, CORINFO_TAILCALL_HELPERS& help);
      bool fgCanTailCallViaJitHelper();
      void fgMorphTailCallViaJitHelper(GenTreeCall* call);
      GenTree* fgCreateCallDispatcherAndGetResult(GenTreeCall*          origCall,
                                                  CORINFO_METHOD_HANDLE callTargetStubHnd,
                                                  CORINFO_METHOD_HANDLE dispatcherHnd);
      GenTree* getLookupTree(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                             CORINFO_LOOKUP*         pLookup,
                             GenTreeFlags            handleFlags,
                             void*                   compileTimeHandle);
      GenTree* getRuntimeLookupTree(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                    CORINFO_LOOKUP*         pLookup,
                                    void*                   compileTimeHandle);
      GenTree* getVirtMethodPointerTree(GenTree*                thisPtr,
                                        CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                        CORINFO_CALL_INFO*      pCallInfo);
      GenTree* getTokenHandleTree(CORINFO_RESOLVED_TOKEN* pResolvedToken, bool parent);
  
      GenTree* fgMorphPotentialTailCall(GenTreeCall* call);
      GenTree* fgGetStubAddrArg(GenTreeCall* call);
      unsigned fgGetArgTabEntryParameterLclNum(GenTreeCall* call, fgArgTabEntry* argTabEntry);
      void fgMorphRecursiveFastTailCallIntoLoop(BasicBlock* block, GenTreeCall* recursiveTailCall);
      Statement* fgAssignRecursiveCallArgToCallerParam(GenTree*         arg,
                                                       fgArgTabEntry*   argTabEntry,
                                                       unsigned         lclParamNum,
                                                       BasicBlock*      block,
                                                       const DebugInfo& callDI,
                                                       Statement*       tmpAssignmentInsertionPoint,
                                                       Statement*       paramAssignmentInsertionPoint);
      GenTree* fgMorphCall(GenTreeCall* call);
      GenTree* fgExpandVirtualVtableCallTarget(GenTreeCall* call);
      void fgMorphCallInline(GenTreeCall* call, InlineResult* result);
      void fgMorphCallInlineHelper(GenTreeCall* call, InlineResult* result, InlineContext** createdContext);
  #if DEBUG
      void fgNoteNonInlineCandidate(Statement* stmt, GenTreeCall* call);
      static fgWalkPreFn fgFindNonInlineCandidate;
  #endif
      GenTree* fgOptimizeDelegateConstructor(GenTreeCall*            call,
                                             CORINFO_CONTEXT_HANDLE* ExactContextHnd,
                                             CORINFO_RESOLVED_TOKEN* ldftnToken);
      GenTree* fgMorphLeaf(GenTree* tree);
      void fgAssignSetVarDef(GenTree* tree);
      GenTree* fgMorphOneAsgBlockOp(GenTree* tree);
      GenTree* fgMorphInitBlock(GenTree* tree);
      GenTree* fgMorphPromoteLocalInitBlock(GenTreeLclVar* destLclNode, GenTree* initVal, unsigned blockSize);
      GenTree* fgMorphGetStructAddr(GenTree** pTree, CORINFO_CLASS_HANDLE clsHnd, bool isRValue = false);
      GenTree* fgMorphBlockOperand(GenTree* tree, var_types asgType, unsigned blockWidth, bool isBlkReqd);
      GenTree* fgMorphCopyBlock(GenTree* tree);
      GenTree* fgMorphStoreDynBlock(GenTreeStoreDynBlk* tree);
      GenTree* fgMorphForRegisterFP(GenTree* tree);
      GenTree* fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac = nullptr);
      GenTree* fgOptimizeCast(GenTreeCast* cast);
      GenTree* fgOptimizeEqualityComparisonWithConst(GenTreeOp* cmp);
      GenTree* fgOptimizeRelationalComparisonWithConst(GenTreeOp* cmp);
      GenTree* fgOptimizeCommutativeArithmetic(GenTreeOp* tree);
      GenTree* fgOptimizeAddition(GenTreeOp* add);
      GenTree* fgOptimizeMultiply(GenTreeOp* mul);
      GenTree* fgOptimizeBitwiseAnd(GenTreeOp* andOp);
      GenTree* fgPropagateCommaThrow(GenTree* parent, GenTreeOp* commaThrow, GenTreeFlags precedingSideEffects);
      GenTree* fgMorphRetInd(GenTreeUnOp* tree);
      GenTree* fgMorphModToSubMulDiv(GenTreeOp* tree);
      GenTree* fgMorphSmpOpOptional(GenTreeOp* tree);
      GenTree* fgMorphMultiOp(GenTreeMultiOp* multiOp);
      GenTree* fgMorphConst(GenTree* tree);
  
      bool fgMorphCanUseLclFldForCopy(unsigned lclNum1, unsigned lclNum2);
  
      GenTreeLclVar* fgMorphTryFoldObjAsLclVar(GenTreeObj* obj, bool destroyNodes = true);
      GenTreeOp* fgMorphCommutative(GenTreeOp* tree);
      GenTree* fgMorphCastedBitwiseOp(GenTreeOp* tree);
  
      GenTree* fgMorphReduceAddOps(GenTree* tree);
  
  public:
      GenTree* fgMorphTree(GenTree* tree, MorphAddrContext* mac = nullptr);
  
  private:
      void fgKillDependentAssertionsSingle(unsigned lclNum DEBUGARG(GenTree* tree));
      void fgKillDependentAssertions(unsigned lclNum DEBUGARG(GenTree* tree));
      void fgMorphTreeDone(GenTree* tree, GenTree* oldTree = nullptr DEBUGARG(int morphNum = 0));
  
      Statement* fgMorphStmt;
  
      unsigned fgGetBigOffsetMorphingTemp(var_types type); // We cache one temp per type to be
                                                           // used when morphing big offset.
  
      //----------------------- Liveness analysis -------------------------------
  
      VARSET_TP fgCurUseSet; // vars used     by block (before an assignment)
      VARSET_TP fgCurDefSet; // vars assigned by block (before a use)
  
      MemoryKindSet fgCurMemoryUse;   // True iff the current basic block uses memory.
      MemoryKindSet fgCurMemoryDef;   // True iff the current basic block modifies memory.
      MemoryKindSet fgCurMemoryHavoc; // True if  the current basic block is known to set memory to a "havoc" value.
  
      bool byrefStatesMatchGcHeapStates; // True iff GcHeap and ByrefExposed memory have all the same def points.
  
      void fgMarkUseDef(GenTreeLclVarCommon* tree);
  
      void fgBeginScopeLife(VARSET_TP* inScope, VarScopeDsc* var);
      void fgEndScopeLife(VARSET_TP* inScope, VarScopeDsc* var);
  
      void fgMarkInScope(BasicBlock* block, VARSET_VALARG_TP inScope);
      void fgUnmarkInScope(BasicBlock* block, VARSET_VALARG_TP unmarkScope);
  
      void fgExtendDbgScopes();
      void fgExtendDbgLifetimes();
  
  #ifdef DEBUG
      void fgDispDebugScopes();
  #endif // DEBUG
  
      //-------------------------------------------------------------------------
      //
      //  The following keeps track of any code we've added for things like array
      //  range checking or explicit calls to enable GC, and so on.
      //
  public:
      struct AddCodeDsc
      {
          AddCodeDsc*     acdNext;
          BasicBlock*     acdDstBlk; // block  to  which we jump
          unsigned        acdData;
          SpecialCodeKind acdKind; // what kind of a special block is this?
  #if !FEATURE_FIXED_OUT_ARGS
          bool     acdStkLvlInit; // has acdStkLvl value been already set?
          unsigned acdStkLvl;     // stack level in stack slots.
  #endif                          // !FEATURE_FIXED_OUT_ARGS
      };
  
  private:
      static unsigned acdHelper(SpecialCodeKind codeKind);
  
      AddCodeDsc* fgAddCodeList;
      bool        fgAddCodeModf;
      bool        fgRngChkThrowAdded;
      AddCodeDsc* fgExcptnTargetCache[SCK_COUNT];
  
      BasicBlock* fgRngChkTarget(BasicBlock* block, SpecialCodeKind kind);
  
      BasicBlock* fgAddCodeRef(BasicBlock* srcBlk, unsigned refData, SpecialCodeKind kind);
  
  public:
      AddCodeDsc* fgFindExcptnTarget(SpecialCodeKind kind, unsigned refData);
  
      bool fgUseThrowHelperBlocks();
  
      AddCodeDsc* fgGetAdditionalCodeDescriptors()
      {
          return fgAddCodeList;
      }
  
  private:
      bool fgIsCodeAdded();
  
      bool fgIsThrowHlpBlk(BasicBlock* block);
  
  #if !FEATURE_FIXED_OUT_ARGS
      unsigned fgThrowHlpBlkStkLevel(BasicBlock* block);
  #endif // !FEATURE_FIXED_OUT_ARGS
  
      unsigned fgBigOffsetMorphingTemps[TYP_COUNT];
  
      unsigned fgCheckInlineDepthAndRecursion(InlineInfo* inlineInfo);
      void fgInvokeInlineeCompiler(GenTreeCall* call, InlineResult* result, InlineContext** createdContext);
      void fgInsertInlineeBlocks(InlineInfo* pInlineInfo);
      Statement* fgInlinePrependStatements(InlineInfo* inlineInfo);
      void fgInlineAppendStatements(InlineInfo* inlineInfo, BasicBlock* block, Statement* stmt);
  
  #if FEATURE_MULTIREG_RET
      GenTree* fgGetStructAsStructPtr(GenTree* tree);
      GenTree* fgAssignStructInlineeToVar(GenTree* child, CORINFO_CLASS_HANDLE retClsHnd);
      void fgAttachStructInlineeToAsg(GenTree* tree, GenTree* child, CORINFO_CLASS_HANDLE retClsHnd);
  #endif // FEATURE_MULTIREG_RET
  
      static fgWalkPreFn  fgUpdateInlineReturnExpressionPlaceHolder;
      static fgWalkPostFn fgLateDevirtualization;
  
  #ifdef DEBUG
      static fgWalkPreFn fgDebugCheckInlineCandidates;
  
      void               CheckNoTransformableIndirectCallsRemain();
      static fgWalkPreFn fgDebugCheckForTransformableIndirectCalls;
  #endif
  
      void fgPromoteStructs();
      void fgMorphStructField(GenTree* tree, GenTree* parent);
      void fgMorphLocalField(GenTree* tree, GenTree* parent);
  
      // Reset the refCount for implicit byrefs.
      void fgResetImplicitByRefRefCount();
  
      // Change implicit byrefs' types from struct to pointer, and for any that were
      // promoted, create new promoted struct temps.
      void fgRetypeImplicitByRefArgs();
  
      // Rewrite appearances of implicit byrefs (manifest the implied additional level of indirection).
      bool fgMorphImplicitByRefArgs(GenTree* tree);
      GenTree* fgMorphImplicitByRefArgs(GenTree* tree, bool isAddr);
  
      // Clear up annotations for any struct promotion temps created for implicit byrefs.
      void fgMarkDemotedImplicitByRefArgs();
  
      void fgMarkAddressExposedLocals();
      void fgMarkAddressExposedLocals(Statement* stmt);
  
      PhaseStatus fgForwardSub();
      bool fgForwardSubBlock(BasicBlock* block);
      bool fgForwardSubStatement(Statement* statement);
  
      static fgWalkPreFn  fgUpdateSideEffectsPre;
      static fgWalkPostFn fgUpdateSideEffectsPost;
  
      // The given local variable, required to be a struct variable, is being assigned via
      // a "lclField", to make it masquerade as an integral type in the ABI.  Make sure that
      // the variable is not enregistered, and is therefore not promoted independently.
      void fgLclFldAssign(unsigned lclNum);
  
      static fgWalkPreFn gtHasLocalsWithAddrOpCB;
  
      enum TypeProducerKind
      {
          TPK_Unknown = 0, // May not be a RuntimeType
          TPK_Handle  = 1, // RuntimeType via handle
          TPK_GetType = 2, // RuntimeType via Object.get_Type()
          TPK_Null    = 3, // Tree value is null
          TPK_Other   = 4  // RuntimeType via other means
      };
  
      TypeProducerKind gtGetTypeProducerKind(GenTree* tree);
      bool gtIsTypeHandleToRuntimeTypeHelper(GenTreeCall* call);
      bool gtIsTypeHandleToRuntimeTypeHandleHelper(GenTreeCall* call, CorInfoHelpFunc* pHelper = nullptr);
      bool gtIsActiveCSE_Candidate(GenTree* tree);
  
      bool fgIsBigOffset(size_t offset);
  
      bool fgNeedReturnSpillTemp();
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           Optimizer                                       XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      void optInit();
  
      GenTree* optRemoveRangeCheck(GenTreeBoundsChk* check, GenTree* comma, Statement* stmt);
      GenTree* optRemoveStandaloneRangeCheck(GenTreeBoundsChk* check, Statement* stmt);
      void optRemoveCommaBasedRangeCheck(GenTree* comma, Statement* stmt);
  
  protected:
      // Do hoisting for all loops.
      void optHoistLoopCode();
  
      // To represent sets of VN's that have already been hoisted in outer loops.
      typedef JitHashTable<ValueNum, JitSmallPrimitiveKeyFuncs<ValueNum>, bool> VNSet;
  
      struct LoopHoistContext
      {
      private:
          // The set of variables hoisted in the current loop (or nullptr if there are none).
          VNSet* m_pHoistedInCurLoop;
  
      public:
          // Value numbers of expressions that have been hoisted in parent loops in the loop nest.
          VNSet m_hoistedInParentLoops;
  
          // Value numbers of expressions that have been hoisted in the current (or most recent) loop in the nest.
          // Previous decisions on loop-invariance of value numbers in the current loop.
          VNSet m_curLoopVnInvariantCache;
  
          VNSet* GetHoistedInCurLoop(Compiler* comp)
          {
              if (m_pHoistedInCurLoop == nullptr)
              {
                  m_pHoistedInCurLoop = new (comp->getAllocatorLoopHoist()) VNSet(comp->getAllocatorLoopHoist());
              }
              return m_pHoistedInCurLoop;
          }
  
          VNSet* ExtractHoistedInCurLoop()
          {
              VNSet* res          = m_pHoistedInCurLoop;
              m_pHoistedInCurLoop = nullptr;
              return res;
          }
  
          LoopHoistContext(Compiler* comp)
              : m_pHoistedInCurLoop(nullptr)
              , m_hoistedInParentLoops(comp->getAllocatorLoopHoist())
              , m_curLoopVnInvariantCache(comp->getAllocatorLoopHoist())
          {
          }
      };
  
      // Do hoisting for loop "lnum" (an index into the optLoopTable), and all loops nested within it.
      // Tracks the expressions that have been hoisted by containing loops by temporarily recording their
      // value numbers in "m_hoistedInParentLoops".  This set is not modified by the call.
      void optHoistLoopNest(unsigned lnum, LoopHoistContext* hoistCtxt);
  
      // Do hoisting for a particular loop ("lnum" is an index into the optLoopTable.)
      // Assumes that expressions have been hoisted in containing loops if their value numbers are in
      // "m_hoistedInParentLoops".
      //
      void optHoistThisLoop(unsigned lnum, LoopHoistContext* hoistCtxt);
  
      // Hoist all expressions in "blocks" that are invariant in loop "loopNum" (an index into the optLoopTable)
      // outside of that loop.  Exempt expressions whose value number is in "m_hoistedInParentLoops"; add VN's of hoisted
      // expressions to "hoistInLoop".
      void optHoistLoopBlocks(unsigned loopNum, ArrayStack<BasicBlock*>* blocks, LoopHoistContext* hoistContext);
  
      // Return true if the tree looks profitable to hoist out of loop 'lnum'.
      bool optIsProfitableToHoistTree(GenTree* tree, unsigned lnum);
  
      // Performs the hoisting 'tree' into the PreHeader for loop 'lnum'
      void optHoistCandidate(GenTree* tree, BasicBlock* treeBb, unsigned lnum, LoopHoistContext* hoistCtxt);
  
      // Returns true iff the ValueNum "vn" represents a value that is loop-invariant in "lnum".
      //   Constants and init values are always loop invariant.
      //   VNPhi's connect VN's to the SSA definition, so we can know if the SSA def occurs in the loop.
      bool optVNIsLoopInvariant(ValueNum vn, unsigned lnum, VNSet* recordedVNs);
  
      // If "blk" is the entry block of a natural loop, returns true and sets "*pLnum" to the index of the loop
      // in the loop table.
      bool optBlockIsLoopEntry(BasicBlock* blk, unsigned* pLnum);
  
      // Records the set of "side effects" of all loops: fields (object instance and static)
      // written to, and SZ-array element type equivalence classes updated.
      void optComputeLoopSideEffects();
  
  #ifdef DEBUG
      bool optAnyChildNotRemoved(unsigned loopNum);
  #endif // DEBUG
  
      // Mark a loop as removed.
      void optMarkLoopRemoved(unsigned loopNum);
  
  private:
      // Requires "lnum" to be the index of an outermost loop in the loop table.  Traverses the body of that loop,
      // including all nested loops, and records the set of "side effects" of the loop: fields (object instance and
      // static) written to, and SZ-array element type equivalence classes updated.
      void optComputeLoopNestSideEffects(unsigned lnum);
  
      // Given a loop number 'lnum' mark it and any nested loops as having 'memoryHavoc'
      void optRecordLoopNestsMemoryHavoc(unsigned lnum, MemoryKindSet memoryHavoc);
  
      // Add the side effects of "blk" (which is required to be within a loop) to all loops of which it is a part.
      // Returns false if we encounter a block that is not marked as being inside a loop.
      //
      bool optComputeLoopSideEffectsOfBlock(BasicBlock* blk);
  
      // Hoist the expression "expr" out of loop "lnum".
      void optPerformHoistExpr(GenTree* expr, BasicBlock* exprBb, unsigned lnum);
  
  public:
      void optOptimizeBools();
  
  public:
      PhaseStatus optInvertLoops();    // Invert loops so they're entered at top and tested at bottom.
      PhaseStatus optOptimizeLayout(); // Optimize the BasicBlock layout of the method
      PhaseStatus optSetBlockWeights();
      PhaseStatus optFindLoopsPhase(); // Finds loops and records them in the loop table
  
      void optFindLoops();
  
      PhaseStatus optCloneLoops();
      void optCloneLoop(unsigned loopInd, LoopCloneContext* context);
      void optEnsureUniqueHead(unsigned loopInd, weight_t ambientWeight);
      PhaseStatus optUnrollLoops(); // Unrolls loops (needs to have cost info)
      void        optRemoveRedundantZeroInits();
  
  protected:
      // This enumeration describes what is killed by a call.
  
      enum callInterf
      {
          CALLINT_NONE,       // no interference                               (most helpers)
          CALLINT_REF_INDIRS, // kills GC ref indirections                     (SETFIELD OBJ)
          CALLINT_SCL_INDIRS, // kills non GC ref indirections                 (SETFIELD non-OBJ)
          CALLINT_ALL_INDIRS, // kills both GC ref and non GC ref indirections (SETFIELD STRUCT)
          CALLINT_ALL,        // kills everything                              (normal method call)
      };
  
      enum class FieldKindForVN
      {
          SimpleStatic,
          WithBaseAddr
      };
  
  public:
      // A "LoopDsc" describes a ("natural") loop.  We (currently) require the body of a loop to be a contiguous (in
      // bbNext order) sequence of basic blocks.  (At times, we may require the blocks in a loop to be "properly numbered"
      // in bbNext order; we use comparisons on the bbNum to decide order.)
      // The blocks that define the body are
      //   top <= entry <= bottom
      // The "head" of the loop is a block outside the loop that has "entry" as a successor. We only support loops with a
      // single 'head' block. The meanings of these blocks are given in the definitions below. Also see the picture at
      // Compiler::optFindNaturalLoops().
      struct LoopDsc
      {
          BasicBlock* lpHead;   // HEAD of the loop (not part of the looping of the loop) -- has ENTRY as a successor.
          BasicBlock* lpTop;    // loop TOP (the back edge from lpBottom reaches here). Lexically first block (in bbNext
                                // order) reachable in this loop.
          BasicBlock* lpEntry;  // the ENTRY in the loop (in most cases TOP or BOTTOM)
          BasicBlock* lpBottom; // loop BOTTOM (from here we have a back edge to the TOP)
          BasicBlock* lpExit;   // if a single exit loop this is the EXIT (in most cases BOTTOM)
  
          callInterf   lpAsgCall;     // "callInterf" for calls in the loop
          ALLVARSET_TP lpAsgVars;     // set of vars assigned within the loop (all vars, not just tracked)
          varRefKinds  lpAsgInds : 8; // set of inds modified within the loop
  
          LoopFlags lpFlags;
  
          unsigned char lpExitCnt; // number of exits from the loop
  
          unsigned char lpParent;  // The index of the most-nested loop that completely contains this one,
                                   // or else BasicBlock::NOT_IN_LOOP if no such loop exists.
          unsigned char lpChild;   // The index of a nested loop, or else BasicBlock::NOT_IN_LOOP if no child exists.
                                   // (Actually, an "immediately" nested loop --
                                   // no other child of this loop is a parent of lpChild.)
          unsigned char lpSibling; // The index of another loop that is an immediate child of lpParent,
                                   // or else BasicBlock::NOT_IN_LOOP.  One can enumerate all the children of a loop
                                   // by following "lpChild" then "lpSibling" links.
  
          bool lpLoopHasMemoryHavoc[MemoryKindCount]; // The loop contains an operation that we assume has arbitrary
                                                      // memory side effects.  If this is set, the fields below
                                                      // may not be accurate (since they become irrelevant.)
  
          VARSET_TP lpVarInOut;  // The set of variables that are IN or OUT during the execution of this loop
          VARSET_TP lpVarUseDef; // The set of variables that are USE or DEF during the execution of this loop
  
          // The following counts are used for hoisting profitability checks.
  
          int lpHoistedExprCount; // The register count for the non-FP expressions from inside this loop that have been
                                  // hoisted
          int lpLoopVarCount;     // The register count for the non-FP LclVars that are read/written inside this loop
          int lpVarInOutCount;    // The register count for the non-FP LclVars that are alive inside or across this loop
  
          int lpHoistedFPExprCount; // The register count for the FP expressions from inside this loop that have been
                                    // hoisted
          int lpLoopVarFPCount;     // The register count for the FP LclVars that are read/written inside this loop
          int lpVarInOutFPCount;    // The register count for the FP LclVars that are alive inside or across this loop
  
          typedef JitHashTable<CORINFO_FIELD_HANDLE, JitPtrKeyFuncs<struct CORINFO_FIELD_STRUCT_>, FieldKindForVN>
                          FieldHandleSet;
          FieldHandleSet* lpFieldsModified; // This has entries for all static field and object instance fields modified
                                            // in the loop.
  
          typedef JitHashTable<CORINFO_CLASS_HANDLE, JitPtrKeyFuncs<struct CORINFO_CLASS_STRUCT_>, bool> ClassHandleSet;
          ClassHandleSet* lpArrayElemTypesModified; // Bits set indicate the set of sz array element types such that
                                                    // arrays of that type are modified
                                                    // in the loop.
  
          // Adds the variable liveness information for 'blk' to 'this' LoopDsc
          void AddVariableLiveness(Compiler* comp, BasicBlock* blk);
  
          inline void AddModifiedField(Compiler* comp, CORINFO_FIELD_HANDLE fldHnd, FieldKindForVN fieldKind);
          // This doesn't *always* take a class handle -- it can also take primitive types, encoded as class handles
          // (shifted left, with a low-order bit set to distinguish.)
          // Use the {Encode/Decode}ElemType methods to construct/destruct these.
          inline void AddModifiedElemType(Compiler* comp, CORINFO_CLASS_HANDLE structHnd);
  
          /* The following values are set only for iterator loops, i.e. has the flag LPFLG_ITER set */
  
          GenTree*   lpIterTree;          // The "i = i <op> const" tree
          unsigned   lpIterVar() const;   // iterator variable #
          int        lpIterConst() const; // the constant with which the iterator is incremented
          genTreeOps lpIterOper() const;  // the type of the operation on the iterator (ASG_ADD, ASG_SUB, etc.)
          void       VERIFY_lpIterTree() const;
  
          var_types lpIterOperType() const; // For overflow instructions
  
          // Set to the block where we found the initialization for LPFLG_CONST_INIT or LPFLG_VAR_INIT loops.
          // Initially, this will be 'head', but 'head' might change if we insert a loop pre-header block.
          BasicBlock* lpInitBlock;
  
          union {
              int lpConstInit;    // initial constant value of iterator
                                  // : Valid if LPFLG_CONST_INIT
              unsigned lpVarInit; // initial local var number to which we initialize the iterator
                                  // : Valid if LPFLG_VAR_INIT
          };
  
          // The following is for LPFLG_ITER loops only (i.e. the loop condition is "i RELOP const or var")
  
          GenTree*   lpTestTree;         // pointer to the node containing the loop test
          genTreeOps lpTestOper() const; // the type of the comparison between the iterator and the limit (GT_LE, GT_GE,
                                         // etc.)
          void VERIFY_lpTestTree() const;
  
          bool     lpIsReversed() const; // true if the iterator node is the second operand in the loop condition
          GenTree* lpIterator() const;   // the iterator node in the loop test
          GenTree* lpLimit() const;      // the limit node in the loop test
  
          // Limit constant value of iterator - loop condition is "i RELOP const"
          // : Valid if LPFLG_CONST_LIMIT
          int lpConstLimit() const;
  
          // The lclVar # in the loop condition ( "i RELOP lclVar" )
          // : Valid if LPFLG_VAR_LIMIT
          unsigned lpVarLimit() const;
  
          // The array length in the loop condition ( "i RELOP arr.len" or "i RELOP arr[i][j].len" )
          // : Valid if LPFLG_ARRLEN_LIMIT
          bool lpArrLenLimit(Compiler* comp, ArrIndex* index) const;
  
          // Returns "true" iff this is a "top entry" loop.
          bool lpIsTopEntry() const
          {
              if (lpHead->bbNext == lpEntry)
              {
                  assert(lpHead->bbFallsThrough());
                  assert(lpTop == lpEntry);
                  return true;
              }
              else
              {
                  return false;
              }
          }
  
          // Returns "true" iff "*this" contains the blk.
          bool lpContains(BasicBlock* blk) const
          {
              return lpTop->bbNum <= blk->bbNum && blk->bbNum <= lpBottom->bbNum;
          }
  
          // Returns "true" iff "*this" (properly) contains the range [top, bottom] (allowing tops
          // to be equal, but requiring bottoms to be different.)
          bool lpContains(BasicBlock* top, BasicBlock* bottom) const
          {
              return lpTop->bbNum <= top->bbNum && bottom->bbNum < lpBottom->bbNum;
          }
  
          // Returns "true" iff "*this" (properly) contains "lp2" (allowing tops to be equal, but requiring
          // bottoms to be different.)
          bool lpContains(const LoopDsc& lp2) const
          {
              return lpContains(lp2.lpTop, lp2.lpBottom);
          }
  
          // Returns "true" iff "*this" is (properly) contained by the range [top, bottom]
          // (allowing tops to be equal, but requiring bottoms to be different.)
          bool lpContainedBy(BasicBlock* top, BasicBlock* bottom) const
          {
              return top->bbNum <= lpTop->bbNum && lpBottom->bbNum < bottom->bbNum;
          }
  
          // Returns "true" iff "*this" is (properly) contained by "lp2"
          // (allowing tops to be equal, but requiring bottoms to be different.)
          bool lpContainedBy(const LoopDsc& lp2) const
          {
              return lpContainedBy(lp2.lpTop, lp2.lpBottom);
          }
  
          // Returns "true" iff "*this" is disjoint from the range [top, bottom].
          bool lpDisjoint(BasicBlock* top, BasicBlock* bottom) const
          {
              return bottom->bbNum < lpTop->bbNum || lpBottom->bbNum < top->bbNum;
          }
          // Returns "true" iff "*this" is disjoint from "lp2".
          bool lpDisjoint(const LoopDsc& lp2) const
          {
              return lpDisjoint(lp2.lpTop, lp2.lpBottom);
          }
  
          // Returns "true" iff the loop is well-formed (see code for defn).
          bool lpWellFormed() const
          {
              return lpTop->bbNum <= lpEntry->bbNum && lpEntry->bbNum <= lpBottom->bbNum &&
                     (lpHead->bbNum < lpTop->bbNum || lpHead->bbNum > lpBottom->bbNum);
          }
  
  #ifdef DEBUG
          void lpValidatePreHeader() const
          {
              // If this is called, we expect there to be a pre-header.
              assert(lpFlags & LPFLG_HAS_PREHEAD);
  
              // The pre-header must unconditionally enter the loop.
              assert(lpHead->GetUniqueSucc() == lpEntry);
  
              // The loop block must be marked as a pre-header.
              assert(lpHead->bbFlags & BBF_LOOP_PREHEADER);
  
              // The loop entry must have a single non-loop predecessor, which is the pre-header.
              // We can't assume here that the bbNum are properly ordered, so we can't do a simple lpContained()
              // check. So, we defer this check, which will be done by `fgDebugCheckLoopTable()`.
          }
  #endif // DEBUG
  
          // LoopBlocks: convenience method for enabling range-based `for` iteration over all the
          // blocks in a loop, e.g.:
          //    for (BasicBlock* const block : loop->LoopBlocks()) ...
          // Currently, the loop blocks are expected to be in linear, lexical, `bbNext` order
          // from `lpTop` through `lpBottom`, inclusive. All blocks in this range are considered
          // to be part of the loop.
          //
          BasicBlockRangeList LoopBlocks() const
          {
              return BasicBlockRangeList(lpTop, lpBottom);
          }
      };
  
  protected:
      bool fgMightHaveLoop(); // returns true if there are any back edges
      bool fgHasLoops;        // True if this method has any loops, set in fgComputeReachability
  
  public:
      LoopDsc*      optLoopTable;        // loop descriptor table
      unsigned char optLoopCount;        // number of tracked loops
      unsigned char loopAlignCandidates; // number of loops identified for alignment
  
      // Every time we rebuild the loop table, we increase the global "loop epoch". Any loop indices or
      // loop table pointers from the previous epoch are invalid.
      // TODO: validate this in some way?
      unsigned optCurLoopEpoch;
  
      void NewLoopEpoch()
      {
          ++optCurLoopEpoch;
          JITDUMP("New loop epoch %d\n", optCurLoopEpoch);
      }
  
  #ifdef DEBUG
      unsigned char loopsAligned; // number of loops actually aligned
  #endif                          // DEBUG
  
      bool optRecordLoop(BasicBlock*   head,
                         BasicBlock*   top,
                         BasicBlock*   entry,
                         BasicBlock*   bottom,
                         BasicBlock*   exit,
                         unsigned char exitCnt);
  
      void optClearLoopIterInfo();
  
  #ifdef DEBUG
      void optPrintLoopInfo(unsigned lnum, bool printVerbose = false);
      void optPrintLoopInfo(const LoopDsc* loop, bool printVerbose = false);
      void optPrintLoopTable();
  #endif
  
  protected:
      unsigned optCallCount;         // number of calls made in the method
      unsigned optIndirectCallCount; // number of virtual, interface and indirect calls made in the method
      unsigned optNativeCallCount;   // number of Pinvoke/Native calls made in the method
      unsigned optLoopsCloned;       // number of loops cloned in the current method.
  
  #ifdef DEBUG
      void optCheckPreds();
  #endif
  
      void optResetLoopInfo();
      void optFindAndScaleGeneralLoopBlocks();
  
      // Determine if there are any potential loops, and set BBF_LOOP_HEAD on potential loop heads.
      void optMarkLoopHeads();
  
      void optScaleLoopBlocks(BasicBlock* begBlk, BasicBlock* endBlk);
  
      void optUnmarkLoopBlocks(BasicBlock* begBlk, BasicBlock* endBlk);
  
      void optUpdateLoopsBeforeRemoveBlock(BasicBlock* block, bool skipUnmarkLoop = false);
  
      bool optIsLoopTestEvalIntoTemp(Statement* testStmt, Statement** newTestStmt);
      unsigned optIsLoopIncrTree(GenTree* incr);
      bool optCheckIterInLoopTest(unsigned loopInd, GenTree* test, BasicBlock* from, BasicBlock* to, unsigned iterVar);
      bool optComputeIterInfo(GenTree* incr, BasicBlock* from, BasicBlock* to, unsigned* pIterVar);
      bool optPopulateInitInfo(unsigned loopInd, BasicBlock* initBlock, GenTree* init, unsigned iterVar);
      bool optExtractInitTestIncr(
          BasicBlock* head, BasicBlock* bottom, BasicBlock* exit, GenTree** ppInit, GenTree** ppTest, GenTree** ppIncr);
  
      void optFindNaturalLoops();
  
      void optIdentifyLoopsForAlignment();
  
      // Ensures that all the loops in the loop nest rooted at "loopInd" (an index into the loop table) are 'canonical' --
      // each loop has a unique "top."  Returns "true" iff the flowgraph has been modified.
      bool optCanonicalizeLoopNest(unsigned char loopInd);
  
      // Ensures that the loop "loopInd" (an index into the loop table) is 'canonical' -- it has a unique "top,"
      // unshared with any other loop.  Returns "true" iff the flowgraph has been modified
      bool optCanonicalizeLoop(unsigned char loopInd);
  
      // Requires "l1" to be a valid loop table index, and not "BasicBlock::NOT_IN_LOOP".
      // Requires "l2" to be a valid loop table index, or else "BasicBlock::NOT_IN_LOOP".
      // Returns true iff "l2" is not NOT_IN_LOOP, and "l1" contains "l2".
      // A loop contains itself.
      bool optLoopContains(unsigned l1, unsigned l2) const;
  
      // Updates the loop table by changing loop "loopInd", whose head is required
      // to be "from", to be "to".  Also performs this transformation for any
      // loop nested in "loopInd" that shares the same head as "loopInd".
      void optUpdateLoopHead(unsigned loopInd, BasicBlock* from, BasicBlock* to);
  
      void optRedirectBlock(BasicBlock* blk, BlockToBlockMap* redirectMap, const bool updatePreds = false);
  
      // Marks the containsCall information to "lnum" and any parent loops.
      void AddContainsCallAllContainingLoops(unsigned lnum);
  
      // Adds the variable liveness information from 'blk' to "lnum" and any parent loops.
      void AddVariableLivenessAllContainingLoops(unsigned lnum, BasicBlock* blk);
  
      // Adds "fldHnd" to the set of modified fields of "lnum" and any parent loops.
      void AddModifiedFieldAllContainingLoops(unsigned lnum, CORINFO_FIELD_HANDLE fldHnd, FieldKindForVN fieldKind);
  
      // Adds "elemType" to the set of modified array element types of "lnum" and any parent loops.
      void AddModifiedElemTypeAllContainingLoops(unsigned lnum, CORINFO_CLASS_HANDLE elemType);
  
      // Requires that "from" and "to" have the same "bbJumpKind" (perhaps because "to" is a clone
      // of "from".)  Copies the jump destination from "from" to "to".
      void optCopyBlkDest(BasicBlock* from, BasicBlock* to);
  
      // Returns true if 'block' is an entry block for any loop in 'optLoopTable'
      bool optIsLoopEntry(BasicBlock* block) const;
  
      // The depth of the loop described by "lnum" (an index into the loop table.) (0 == top level)
      unsigned optLoopDepth(unsigned lnum)
      {
          assert(lnum < optLoopCount);
          unsigned depth = 0;
          while ((lnum = optLoopTable[lnum].lpParent) != BasicBlock::NOT_IN_LOOP)
          {
              ++depth;
          }
          return depth;
      }
  
      // Struct used in optInvertWhileLoop to count interesting constructs to boost the profitability score.
      struct OptInvertCountTreeInfoType
      {
          int sharedStaticHelperCount;
          int arrayLengthCount;
      };
  
      static fgWalkResult optInvertCountTreeInfo(GenTree** pTree, fgWalkData* data);
  
      bool optInvertWhileLoop(BasicBlock* block);
  
  private:
      static bool optIterSmallOverflow(int iterAtExit, var_types incrType);
      static bool optIterSmallUnderflow(int iterAtExit, var_types decrType);
  
      bool optComputeLoopRep(int        constInit,
                             int        constLimit,
                             int        iterInc,
                             genTreeOps iterOper,
                             var_types  iterType,
                             genTreeOps testOper,
                             bool       unsignedTest,
                             bool       dupCond,
                             unsigned*  iterCount);
  
      static fgWalkPreFn optIsVarAssgCB;
  
  protected:
      bool optIsVarAssigned(BasicBlock* beg, BasicBlock* end, GenTree* skip, unsigned var);
  
      bool optIsVarAssgLoop(unsigned lnum, unsigned var);
  
      int optIsSetAssgLoop(unsigned lnum, ALLVARSET_VALARG_TP vars, varRefKinds inds = VR_NONE);
  
      bool optNarrowTree(GenTree* tree, var_types srct, var_types dstt, ValueNumPair vnpNarrow, bool doit);
  
  protected:
      //  The following is the upper limit on how many expressions we'll keep track
      //  of for the CSE analysis.
      //
      static const unsigned MAX_CSE_CNT = EXPSET_SZ;
  
      static const int MIN_CSE_COST = 2;
  
      // BitVec trait information only used by the optCSE_canSwap() method, for the  CSE_defMask and CSE_useMask.
      // This BitVec uses one bit per CSE candidate
      BitVecTraits* cseMaskTraits; // one bit per CSE candidate
  
      // BitVec trait information for computing CSE availability using the CSE_DataFlow algorithm.
      // Two bits are allocated per CSE candidate to compute CSE availability
      // plus an extra bit to handle the initial unvisited case.
      // (See CSE_DataFlow::EndMerge for an explanation of why this is necessary.)
      //
      // The two bits per CSE candidate have the following meanings:
      //     11 - The CSE is available, and is also available when considering calls as killing availability.
      //     10 - The CSE is available, but is not available when considering calls as killing availability.
      //     00 - The CSE is not available
      //     01 - An illegal combination
      //
      BitVecTraits* cseLivenessTraits;
  
      //-----------------------------------------------------------------------------------------------------------------
      // getCSEnum2bit: Return the normalized index to use in the EXPSET_TP for the CSE with the given CSE index.
      // Each GenTree has a `gtCSEnum` field. Zero is reserved to mean this node is not a CSE, positive values indicate
      // CSE uses, and negative values indicate CSE defs. The caller must pass a non-zero positive value, as from
      // GET_CSE_INDEX().
      //
      static unsigned genCSEnum2bit(unsigned CSEnum)
      {
          assert((CSEnum > 0) && (CSEnum <= MAX_CSE_CNT));
          return CSEnum - 1;
      }
  
      //-----------------------------------------------------------------------------------------------------------------
      // getCSEAvailBit: Return the bit used by CSE dataflow sets (bbCseGen, etc.) for the availability bit for a CSE.
      //
      static unsigned getCSEAvailBit(unsigned CSEnum)
      {
          return genCSEnum2bit(CSEnum) * 2;
      }
  
      //-----------------------------------------------------------------------------------------------------------------
      // getCSEAvailCrossCallBit: Return the bit used by CSE dataflow sets (bbCseGen, etc.) for the availability bit
      // for a CSE considering calls as killing availability bit (see description above).
      //
      static unsigned getCSEAvailCrossCallBit(unsigned CSEnum)
      {
          return getCSEAvailBit(CSEnum) + 1;
      }
  
      void optPrintCSEDataFlowSet(EXPSET_VALARG_TP cseDataFlowSet, bool includeBits = true);
  
      EXPSET_TP cseCallKillsMask; // Computed once - A mask that is used to kill available CSEs at callsites
  
      /* Generic list of nodes - used by the CSE logic */
  
      struct treeLst
      {
          treeLst* tlNext;
          GenTree* tlTree;
      };
  
      struct treeStmtLst
      {
          treeStmtLst* tslNext;
          GenTree*     tslTree;  // tree node
          Statement*   tslStmt;  // statement containing the tree
          BasicBlock*  tslBlock; // block containing the statement
      };
  
      // The following logic keeps track of expressions via a simple hash table.
  
      struct CSEdsc
      {
          CSEdsc*  csdNextInBucket;  // used by the hash table
          size_t   csdHashKey;       // the orginal hashkey
          ssize_t  csdConstDefValue; // When we CSE similar constants, this is the value that we use as the def
          ValueNum csdConstDefVN;    // When we CSE similar constants, this is the ValueNumber that we use for the LclVar
                                     // assignment
          unsigned csdIndex;         // 1..optCSECandidateCount
          bool     csdIsSharedConst; // true if this CSE is a shared const
          bool     csdLiveAcrossCall;
  
          unsigned short csdDefCount; // definition   count
          unsigned short csdUseCount; // use          count  (excluding the implicit uses at defs)
  
          weight_t csdDefWtCnt; // weighted def count
          weight_t csdUseWtCnt; // weighted use count  (excluding the implicit uses at defs)
  
          GenTree*    csdTree;  // treenode containing the 1st occurrence
          Statement*  csdStmt;  // stmt containing the 1st occurrence
          BasicBlock* csdBlock; // block containing the 1st occurrence
  
          treeStmtLst* csdTreeList; // list of matching tree nodes: head
          treeStmtLst* csdTreeLast; // list of matching tree nodes: tail
  
          // ToDo: This can be removed when gtGetStructHandleIfPresent stops guessing
          // and GT_IND nodes always have valid struct handle.
          //
          CORINFO_CLASS_HANDLE csdStructHnd; // The class handle, currently needed to create a SIMD LclVar in PerformCSE
          bool                 csdStructHndMismatch;
  
          ValueNum defExcSetPromise; // The exception set that is now required for all defs of this CSE.
                                     // This will be set to NoVN if we decide to abandon this CSE
  
          ValueNum defExcSetCurrent; // The set of exceptions we currently can use for CSE uses.
  
          ValueNum defConservNormVN; // if all def occurrences share the same conservative normal value
                                     // number, this will reflect it; otherwise, NoVN.
                                     // not used for shared const CSE's
      };
  
      static const size_t s_optCSEhashSizeInitial;
      static const size_t s_optCSEhashGrowthFactor;
      static const size_t s_optCSEhashBucketSize;
      size_t              optCSEhashSize;                 // The current size of hashtable
      size_t              optCSEhashCount;                // Number of entries in hashtable
      size_t              optCSEhashMaxCountBeforeResize; // Number of entries before resize
      CSEdsc**            optCSEhash;
      CSEdsc**            optCSEtab;
  
      typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, GenTree*> NodeToNodeMap;
  
      NodeToNodeMap* optCseCheckedBoundMap; // Maps bound nodes to ancestor compares that should be
                                            // re-numbered with the bound to improve range check elimination
  
      // Given a compare, look for a cse candidate checked bound feeding it and add a map entry if found.
      void optCseUpdateCheckedBoundMap(GenTree* compare);
  
      void optCSEstop();
  
      CSEdsc* optCSEfindDsc(unsigned index);
      bool optUnmarkCSE(GenTree* tree);
  
      // user defined callback data for the tree walk function optCSE_MaskHelper()
      struct optCSE_MaskData
      {
          EXPSET_TP CSE_defMask;
          EXPSET_TP CSE_useMask;
      };
  
      // Treewalk helper for optCSE_DefMask and optCSE_UseMask
      static fgWalkPreFn optCSE_MaskHelper;
  
      // This function walks all the node for an given tree
      // and return the mask of CSE definitions and uses for the tree
      //
      void optCSE_GetMaskData(GenTree* tree, optCSE_MaskData* pMaskData);
  
      // Given a binary tree node return true if it is safe to swap the order of evaluation for op1 and op2.
      bool optCSE_canSwap(GenTree* firstNode, GenTree* secondNode);
  
      struct optCSEcostCmpEx
      {
          bool operator()(const CSEdsc* op1, const CSEdsc* op2);
      };
      struct optCSEcostCmpSz
      {
          bool operator()(const CSEdsc* op1, const CSEdsc* op2);
      };
  
      void optCleanupCSEs();
  
  #ifdef DEBUG
      void optEnsureClearCSEInfo();
  #endif // DEBUG
  
      static bool Is_Shared_Const_CSE(size_t key)
      {
          return ((key & TARGET_SIGN_BIT) != 0);
      }
  
      // returns the encoded key
      static size_t Encode_Shared_Const_CSE_Value(size_t key)
      {
          return TARGET_SIGN_BIT | (key >> CSE_CONST_SHARED_LOW_BITS);
      }
  
      // returns the orginal key
      static size_t Decode_Shared_Const_CSE_Value(size_t enckey)
      {
          assert(Is_Shared_Const_CSE(enckey));
          return (enckey & ~TARGET_SIGN_BIT) << CSE_CONST_SHARED_LOW_BITS;
      }
  
  /**************************************************************************
   *                   Value Number based CSEs
   *************************************************************************/
  
  // String to use for formatting CSE numbers. Note that this is the positive number, e.g., from GET_CSE_INDEX().
  #define FMT_CSE "CSE #%02u"
  
  public:
      void optOptimizeValnumCSEs();
  
  protected:
      void     optValnumCSE_Init();
      unsigned optValnumCSE_Index(GenTree* tree, Statement* stmt);
      bool optValnumCSE_Locate();
      void optValnumCSE_InitDataFlow();
      void optValnumCSE_DataFlow();
      void optValnumCSE_Availablity();
      void optValnumCSE_Heuristic();
  
      bool     optDoCSE;             // True when we have found a duplicate CSE tree
      bool     optValnumCSE_phase;   // True when we are executing the optOptimizeValnumCSEs() phase
      unsigned optCSECandidateCount; // Count of CSE's candidates
      unsigned optCSEstart;          // The first local variable number that is a CSE
      unsigned optCSEcount;          // The total count of CSE's introduced.
      weight_t optCSEweight;         // The weight of the current block when we are doing PerformCSE
  
      bool optIsCSEcandidate(GenTree* tree);
  
      // lclNumIsTrueCSE returns true if the LclVar was introduced by the CSE phase of the compiler
      //
      bool lclNumIsTrueCSE(unsigned lclNum) const
      {
          return ((optCSEcount > 0) && (lclNum >= optCSEstart) && (lclNum < optCSEstart + optCSEcount));
      }
  
      //  lclNumIsCSE returns true if the LclVar should be treated like a CSE with regards to constant prop.
      //
      bool lclNumIsCSE(unsigned lclNum) const
      {
          return lvaGetDesc(lclNum)->lvIsCSE;
      }
  
  #ifdef DEBUG
      bool optConfigDisableCSE();
      bool optConfigDisableCSE2();
  #endif
  
      void optOptimizeCSEs();
  
      struct isVarAssgDsc
      {
          GenTree*     ivaSkip;
          ALLVARSET_TP ivaMaskVal; // Set of variables assigned to.  This is a set of all vars, not tracked vars.
  #ifdef DEBUG
          void* ivaSelf;
  #endif
          unsigned    ivaVar;            // Variable we are interested in, or -1
          varRefKinds ivaMaskInd;        // What kind of indirect assignments are there?
          callInterf  ivaMaskCall;       // What kind of calls are there?
          bool        ivaMaskIncomplete; // Variables not representable in ivaMaskVal were assigned to.
      };
  
      static callInterf optCallInterf(GenTreeCall* call);
  
  public:
      // VN based copy propagation.
      typedef ArrayStack<GenTree*> GenTreePtrStack;
      typedef JitHashTable<unsigned, JitSmallPrimitiveKeyFuncs<unsigned>, GenTreePtrStack*> LclNumToGenTreePtrStack;
  
      // Copy propagation functions.
      void optCopyProp(Statement* stmt, GenTreeLclVarCommon* tree, unsigned lclNum, LclNumToGenTreePtrStack* curSsaName);
      void optBlockCopyPropPopStacks(BasicBlock* block, LclNumToGenTreePtrStack* curSsaName);
      void optBlockCopyProp(BasicBlock* block, LclNumToGenTreePtrStack* curSsaName);
      unsigned optIsSsaLocal(GenTreeLclVarCommon* lclNode);
      int optCopyProp_LclVarScore(LclVarDsc* lclVarDsc, LclVarDsc* copyVarDsc, bool preferOp2);
      void optVnCopyProp();
      INDEBUG(void optDumpCopyPropStack(LclNumToGenTreePtrStack* curSsaName));
  
      /**************************************************************************
       *               Early value propagation
       *************************************************************************/
      struct SSAName
      {
          unsigned m_lvNum;
          unsigned m_ssaNum;
  
          SSAName(unsigned lvNum, unsigned ssaNum) : m_lvNum(lvNum), m_ssaNum(ssaNum)
          {
          }
  
          static unsigned GetHashCode(SSAName ssaNm)
          {
              return (ssaNm.m_lvNum << 16) | (ssaNm.m_ssaNum);
          }
  
          static bool Equals(SSAName ssaNm1, SSAName ssaNm2)
          {
              return (ssaNm1.m_lvNum == ssaNm2.m_lvNum) && (ssaNm1.m_ssaNum == ssaNm2.m_ssaNum);
          }
      };
  
  #define OMF_HAS_NEWARRAY 0x00000001         // Method contains 'new' of an array
  #define OMF_HAS_NEWOBJ 0x00000002           // Method contains 'new' of an object type.
  #define OMF_HAS_ARRAYREF 0x00000004         // Method contains array element loads or stores.
  #define OMF_HAS_NULLCHECK 0x00000008        // Method contains null check.
  #define OMF_HAS_FATPOINTER 0x00000010       // Method contains call, that needs fat pointer transformation.
  #define OMF_HAS_OBJSTACKALLOC 0x00000020    // Method contains an object allocated on the stack.
  #define OMF_HAS_GUARDEDDEVIRT 0x00000040    // Method contains guarded devirtualization candidate
  #define OMF_HAS_EXPRUNTIMELOOKUP 0x00000080 // Method contains a runtime lookup to an expandable dictionary.
  #define OMF_HAS_PATCHPOINT 0x00000100       // Method contains patchpoints
  #define OMF_NEEDS_GCPOLLS 0x00000200        // Method needs GC polls
  #define OMF_HAS_FROZEN_STRING 0x00000400    // Method has a frozen string (REF constant int), currently only on CoreRT.
  #define OMF_HAS_PARTIAL_COMPILATION_PATCHPOINT 0x00000800 // Method contains partial compilation patchpoints
  #define OMF_HAS_TAILCALL_SUCCESSOR 0x00001000             // Method has potential tail call in a non BBJ_RETURN block
  
      bool doesMethodHaveFatPointer()
      {
          return (optMethodFlags & OMF_HAS_FATPOINTER) != 0;
      }
  
      void setMethodHasFatPointer()
      {
          optMethodFlags |= OMF_HAS_FATPOINTER;
      }
  
      void clearMethodHasFatPointer()
      {
          optMethodFlags &= ~OMF_HAS_FATPOINTER;
      }
  
      void addFatPointerCandidate(GenTreeCall* call);
  
      bool doesMethodHaveFrozenString() const
      {
          return (optMethodFlags & OMF_HAS_FROZEN_STRING) != 0;
      }
  
      void setMethodHasFrozenString()
      {
          optMethodFlags |= OMF_HAS_FROZEN_STRING;
      }
  
      bool doesMethodHaveGuardedDevirtualization() const
      {
          return (optMethodFlags & OMF_HAS_GUARDEDDEVIRT) != 0;
      }
  
      void setMethodHasGuardedDevirtualization()
      {
          optMethodFlags |= OMF_HAS_GUARDEDDEVIRT;
      }
  
      void clearMethodHasGuardedDevirtualization()
      {
          optMethodFlags &= ~OMF_HAS_GUARDEDDEVIRT;
      }
  
      void considerGuardedDevirtualization(GenTreeCall*            call,
                                           IL_OFFSET               ilOffset,
                                           bool                    isInterface,
                                           CORINFO_METHOD_HANDLE   baseMethod,
                                           CORINFO_CLASS_HANDLE    baseClass,
                                           CORINFO_CONTEXT_HANDLE* pContextHandle DEBUGARG(CORINFO_CLASS_HANDLE objClass)
                                               DEBUGARG(const char* objClassName));
  
      void addGuardedDevirtualizationCandidate(GenTreeCall*          call,
                                               CORINFO_METHOD_HANDLE methodHandle,
                                               CORINFO_CLASS_HANDLE  classHandle,
                                               unsigned              methodAttr,
                                               unsigned              classAttr,
                                               unsigned              likelihood);
  
      bool doesMethodHaveExpRuntimeLookup()
      {
          return (optMethodFlags & OMF_HAS_EXPRUNTIMELOOKUP) != 0;
      }
  
      void setMethodHasExpRuntimeLookup()
      {
          optMethodFlags |= OMF_HAS_EXPRUNTIMELOOKUP;
      }
  
      void clearMethodHasExpRuntimeLookup()
      {
          optMethodFlags &= ~OMF_HAS_EXPRUNTIMELOOKUP;
      }
  
      void addExpRuntimeLookupCandidate(GenTreeCall* call);
  
      bool doesMethodHavePatchpoints()
      {
          return (optMethodFlags & OMF_HAS_PATCHPOINT) != 0;
      }
  
      void setMethodHasPatchpoint()
      {
          optMethodFlags |= OMF_HAS_PATCHPOINT;
      }
  
      bool doesMethodHavePartialCompilationPatchpoints()
      {
          return (optMethodFlags & OMF_HAS_PARTIAL_COMPILATION_PATCHPOINT) != 0;
      }
  
      void setMethodHasPartialCompilationPatchpoint()
      {
          optMethodFlags |= OMF_HAS_PARTIAL_COMPILATION_PATCHPOINT;
      }
  
      unsigned optMethodFlags;
  
      bool doesMethodHaveNoReturnCalls()
      {
          return optNoReturnCallCount > 0;
      }
  
      void setMethodHasNoReturnCalls()
      {
          optNoReturnCallCount++;
      }
  
      unsigned optNoReturnCallCount;
  
      // Recursion bound controls how far we can go backwards tracking for a SSA value.
      // No throughput diff was found with backward walk bound between 3-8.
      static const int optEarlyPropRecurBound = 5;
  
      enum class optPropKind
      {
          OPK_INVALID,
          OPK_ARRAYLEN,
          OPK_NULLCHECK
      };
  
      typedef JitHashTable<unsigned, JitSmallPrimitiveKeyFuncs<unsigned>, GenTree*> LocalNumberToNullCheckTreeMap;
  
      GenTree* getArrayLengthFromAllocation(GenTree* tree DEBUGARG(BasicBlock* block));
      GenTree* optPropGetValueRec(unsigned lclNum, unsigned ssaNum, optPropKind valueKind, int walkDepth);
      GenTree* optPropGetValue(unsigned lclNum, unsigned ssaNum, optPropKind valueKind);
      GenTree* optEarlyPropRewriteTree(GenTree* tree, LocalNumberToNullCheckTreeMap* nullCheckMap);
      bool optDoEarlyPropForBlock(BasicBlock* block);
      bool optDoEarlyPropForFunc();
      void optEarlyProp();
      void optFoldNullCheck(GenTree* tree, LocalNumberToNullCheckTreeMap* nullCheckMap);
      GenTree* optFindNullCheckToFold(GenTree* tree, LocalNumberToNullCheckTreeMap* nullCheckMap);
      bool optIsNullCheckFoldingLegal(GenTree*    tree,
                                      GenTree*    nullCheckTree,
                                      GenTree**   nullCheckParent,
                                      Statement** nullCheckStmt);
      bool optCanMoveNullCheckPastTree(GenTree* tree,
                                       unsigned nullCheckLclNum,
                                       bool     isInsideTry,
                                       bool     checkSideEffectSummary);
  #if DEBUG
      void optCheckFlagsAreSet(unsigned    methodFlag,
                               const char* methodFlagStr,
                               unsigned    bbFlag,
                               const char* bbFlagStr,
                               GenTree*    tree,
                               BasicBlock* basicBlock);
  #endif
  
      // Redundant branch opts
      //
      PhaseStatus optRedundantBranches();
      bool optRedundantRelop(BasicBlock* const block);
      bool optRedundantBranch(BasicBlock* const block);
      bool optJumpThread(BasicBlock* const block, BasicBlock* const domBlock, bool domIsSameRelop);
      bool optReachable(BasicBlock* const fromBlock, BasicBlock* const toBlock, BasicBlock* const excludedBlock);
  
      /**************************************************************************
       *               Value/Assertion propagation
       *************************************************************************/
  public:
      // Data structures for assertion prop
      BitVecTraits* apTraits;
      ASSERT_TP     apFull;
  
      enum optAssertionKind
      {
          OAK_INVALID,
          OAK_EQUAL,
          OAK_NOT_EQUAL,
          OAK_SUBRANGE,
          OAK_NO_THROW,
          OAK_COUNT
      };
  
      enum optOp1Kind
      {
          O1K_INVALID,
          O1K_LCLVAR,
          O1K_ARR_BND,
          O1K_BOUND_OPER_BND,
          O1K_BOUND_LOOP_BND,
          O1K_CONSTANT_LOOP_BND,
          O1K_EXACT_TYPE,
          O1K_SUBTYPE,
          O1K_VALUE_NUMBER,
          O1K_COUNT
      };
  
      enum optOp2Kind
      {
          O2K_INVALID,
          O2K_LCLVAR_COPY,
          O2K_IND_CNS_INT,
          O2K_CONST_INT,
          O2K_CONST_LONG,
          O2K_CONST_DOUBLE,
          O2K_SUBRANGE,
          O2K_COUNT
      };
  
      struct AssertionDsc
      {
          optAssertionKind assertionKind;
          struct SsaVar
          {
              unsigned lclNum; // assigned to or property of this local var number
              unsigned ssaNum;
          };
          struct ArrBnd
          {
              ValueNum vnIdx;
              ValueNum vnLen;
          };
          struct AssertionDscOp1
          {
              optOp1Kind kind; // a normal LclVar, or Exact-type or Subtype
              ValueNum   vn;
              union {
                  SsaVar lcl;
                  ArrBnd bnd;
              };
          } op1;
          struct AssertionDscOp2
          {
              optOp2Kind kind; // a const or copy assignment
              ValueNum   vn;
              struct IntVal
              {
                  ssize_t iconVal; // integer
  #if !defined(HOST_64BIT)
                  unsigned padding; // unused; ensures iconFlags does not overlap lconVal
  #endif
                  GenTreeFlags iconFlags; // gtFlags
              };
              union {
                  struct
                  {
                      SsaVar        lcl;
                      FieldSeqNode* zeroOffsetFieldSeq;
                  };
                  IntVal        u1;
                  __int64       lconVal;
                  double        dconVal;
                  IntegralRange u2;
              };
          } op2;
  
          bool IsCheckedBoundArithBound()
          {
              return ((assertionKind == OAK_EQUAL || assertionKind == OAK_NOT_EQUAL) && op1.kind == O1K_BOUND_OPER_BND);
          }
          bool IsCheckedBoundBound()
          {
              return ((assertionKind == OAK_EQUAL || assertionKind == OAK_NOT_EQUAL) && op1.kind == O1K_BOUND_LOOP_BND);
          }
          bool IsConstantBound()
          {
              return ((assertionKind == OAK_EQUAL || assertionKind == OAK_NOT_EQUAL) &&
                      op1.kind == O1K_CONSTANT_LOOP_BND);
          }
          bool IsBoundsCheckNoThrow()
          {
              return ((assertionKind == OAK_NO_THROW) && (op1.kind == O1K_ARR_BND));
          }
  
          bool IsCopyAssertion()
          {
              return ((assertionKind == OAK_EQUAL) && (op1.kind == O1K_LCLVAR) && (op2.kind == O2K_LCLVAR_COPY));
          }
  
          bool IsConstantInt32Assertion()
          {
              return ((assertionKind == OAK_EQUAL) || (assertionKind == OAK_NOT_EQUAL)) && (op2.kind == O2K_CONST_INT);
          }
  
          static bool SameKind(AssertionDsc* a1, AssertionDsc* a2)
          {
              return a1->assertionKind == a2->assertionKind && a1->op1.kind == a2->op1.kind &&
                     a1->op2.kind == a2->op2.kind;
          }
  
          static bool ComplementaryKind(optAssertionKind kind, optAssertionKind kind2)
          {
              if (kind == OAK_EQUAL)
              {
                  return kind2 == OAK_NOT_EQUAL;
              }
              else if (kind == OAK_NOT_EQUAL)
              {
                  return kind2 == OAK_EQUAL;
              }
              return false;
          }
  
          bool HasSameOp1(AssertionDsc* that, bool vnBased)
          {
              if (op1.kind != that->op1.kind)
              {
                  return false;
              }
              else if (op1.kind == O1K_ARR_BND)
              {
                  assert(vnBased);
                  return (op1.bnd.vnIdx == that->op1.bnd.vnIdx) && (op1.bnd.vnLen == that->op1.bnd.vnLen);
              }
              else
              {
                  return ((vnBased && (op1.vn == that->op1.vn)) ||
                          (!vnBased && (op1.lcl.lclNum == that->op1.lcl.lclNum)));
              }
          }
  
          bool HasSameOp2(AssertionDsc* that, bool vnBased)
          {
              if (op2.kind != that->op2.kind)
              {
                  return false;
              }
  
              switch (op2.kind)
              {
                  case O2K_IND_CNS_INT:
                  case O2K_CONST_INT:
                      return ((op2.u1.iconVal == that->op2.u1.iconVal) && (op2.u1.iconFlags == that->op2.u1.iconFlags));
  
                  case O2K_CONST_LONG:
                      return (op2.lconVal == that->op2.lconVal);
  
                  case O2K_CONST_DOUBLE:
                      // exact match because of positive and negative zero.
                      return (memcmp(&op2.dconVal, &that->op2.dconVal, sizeof(double)) == 0);
  
                  case O2K_LCLVAR_COPY:
                      return (op2.lcl.lclNum == that->op2.lcl.lclNum) &&
                             (!vnBased || op2.lcl.ssaNum == that->op2.lcl.ssaNum) &&
                             (op2.zeroOffsetFieldSeq == that->op2.zeroOffsetFieldSeq);
  
                  case O2K_SUBRANGE:
                      return op2.u2.Equals(that->op2.u2);
  
                  case O2K_INVALID:
                      // we will return false
                      break;
  
                  default:
                      assert(!"Unexpected value for op2.kind in AssertionDsc.");
                      break;
              }
  
              return false;
          }
  
          bool Complementary(AssertionDsc* that, bool vnBased)
          {
              return ComplementaryKind(assertionKind, that->assertionKind) && HasSameOp1(that, vnBased) &&
                     HasSameOp2(that, vnBased);
          }
  
          bool Equals(AssertionDsc* that, bool vnBased)
          {
              if (assertionKind != that->assertionKind)
              {
                  return false;
              }
              else if (assertionKind == OAK_NO_THROW)
              {
                  assert(op2.kind == O2K_INVALID);
                  return HasSameOp1(that, vnBased);
              }
              else
              {
                  return HasSameOp1(that, vnBased) && HasSameOp2(that, vnBased);
              }
          }
      };
  
  protected:
      static fgWalkPreFn optAddCopiesCallback;
      static fgWalkPreFn optVNAssertionPropCurStmtVisitor;
      unsigned           optAddCopyLclNum;
      GenTree*           optAddCopyAsgnNode;
  
      bool optLocalAssertionProp;  // indicates that we are performing local assertion prop
      bool optAssertionPropagated; // set to true if we modified the trees
      bool optAssertionPropagatedCurrentStmt;
  #ifdef DEBUG
      GenTree* optAssertionPropCurrentTree;
  #endif
      AssertionIndex*            optComplementaryAssertionMap;
      JitExpandArray<ASSERT_TP>* optAssertionDep; // table that holds dependent assertions (assertions
                                                  // using the value of a local var) for each local var
      AssertionDsc*  optAssertionTabPrivate;      // table that holds info about value assignments
      AssertionIndex optAssertionCount;           // total number of assertions in the assertion table
      AssertionIndex optMaxAssertionCount;
  
  public:
      void optVnNonNullPropCurStmt(BasicBlock* block, Statement* stmt, GenTree* tree);
      fgWalkResult optVNConstantPropCurStmt(BasicBlock* block, Statement* stmt, GenTree* tree);
      GenTree* optVNConstantPropOnJTrue(BasicBlock* block, GenTree* test);
      GenTree* optVNConstantPropOnTree(BasicBlock* block, GenTree* tree);
      GenTree* optExtractSideEffListFromConst(GenTree* tree);
  
      AssertionIndex GetAssertionCount()
      {
          return optAssertionCount;
      }
      ASSERT_TP* bbJtrueAssertionOut;
      typedef JitHashTable<ValueNum, JitSmallPrimitiveKeyFuncs<ValueNum>, ASSERT_TP> ValueNumToAssertsMap;
      ValueNumToAssertsMap* optValueNumToAsserts;
  
      // Assertion prop helpers.
      ASSERT_TP& GetAssertionDep(unsigned lclNum);
      AssertionDsc* optGetAssertion(AssertionIndex assertIndex);
      void optAssertionInit(bool isLocalProp);
      void optAssertionTraitsInit(AssertionIndex assertionCount);
      void optAssertionReset(AssertionIndex limit);
      void optAssertionRemove(AssertionIndex index);
  
      // Assertion prop data flow functions.
      void       optAssertionPropMain();
      Statement* optVNAssertionPropCurStmt(BasicBlock* block, Statement* stmt);
      bool optIsTreeKnownIntValue(bool vnBased, GenTree* tree, ssize_t* pConstant, GenTreeFlags* pIconFlags);
      ASSERT_TP* optInitAssertionDataflowFlags();
      ASSERT_TP* optComputeAssertionGen();
  
      // Assertion Gen functions.
      void optAssertionGen(GenTree* tree);
      AssertionIndex optAssertionGenCast(GenTreeCast* cast);
      AssertionIndex optAssertionGenPhiDefn(GenTree* tree);
      AssertionInfo optCreateJTrueBoundsAssertion(GenTree* tree);
      AssertionInfo optAssertionGenJtrue(GenTree* tree);
      AssertionIndex optCreateJtrueAssertions(GenTree*                   op1,
                                              GenTree*                   op2,
                                              Compiler::optAssertionKind assertionKind,
                                              bool                       helperCallArgs = false);
      AssertionIndex optFindComplementary(AssertionIndex assertionIndex);
      void optMapComplementary(AssertionIndex assertionIndex, AssertionIndex index);
  
      // Assertion creation functions.
      AssertionIndex optCreateAssertion(GenTree*         op1,
                                        GenTree*         op2,
                                        optAssertionKind assertionKind,
                                        bool             helperCallArgs = false);
  
      AssertionIndex optFinalizeCreatingAssertion(AssertionDsc* assertion);
  
      bool optTryExtractSubrangeAssertion(GenTree* source, IntegralRange* pRange);
  
      void optCreateComplementaryAssertion(AssertionIndex assertionIndex,
                                           GenTree*       op1,
                                           GenTree*       op2,
                                           bool           helperCallArgs = false);
  
      bool optAssertionVnInvolvesNan(AssertionDsc* assertion);
      AssertionIndex optAddAssertion(AssertionDsc* assertion);
      void optAddVnAssertionMapping(ValueNum vn, AssertionIndex index);
  #ifdef DEBUG
      void optPrintVnAssertionMapping();
  #endif
      ASSERT_TP optGetVnMappedAssertions(ValueNum vn);
  
      // Used for respective assertion propagations.
      AssertionIndex optAssertionIsSubrange(GenTree* tree, IntegralRange range, ASSERT_VALARG_TP assertions);
      AssertionIndex optAssertionIsSubtype(GenTree* tree, GenTree* methodTableArg, ASSERT_VALARG_TP assertions);
      AssertionIndex optAssertionIsNonNullInternal(GenTree* op, ASSERT_VALARG_TP assertions DEBUGARG(bool* pVnBased));
      bool optAssertionIsNonNull(GenTree*         op,
                                 ASSERT_VALARG_TP assertions DEBUGARG(bool* pVnBased) DEBUGARG(AssertionIndex* pIndex));
  
      // Used for Relop propagation.
      AssertionIndex optGlobalAssertionIsEqualOrNotEqual(ASSERT_VALARG_TP assertions, GenTree* op1, GenTree* op2);
      AssertionIndex optGlobalAssertionIsEqualOrNotEqualZero(ASSERT_VALARG_TP assertions, GenTree* op1);
      AssertionIndex optLocalAssertionIsEqualOrNotEqual(
          optOp1Kind op1Kind, unsigned lclNum, optOp2Kind op2Kind, ssize_t cnsVal, ASSERT_VALARG_TP assertions);
  
      // Assertion prop for lcl var functions.
      bool optAssertionProp_LclVarTypeCheck(GenTree* tree, LclVarDsc* lclVarDsc, LclVarDsc* copyVarDsc);
      GenTree* optCopyAssertionProp(AssertionDsc*        curAssertion,
                                    GenTreeLclVarCommon* tree,
                                    Statement* stmt DEBUGARG(AssertionIndex index));
      GenTree* optConstantAssertionProp(AssertionDsc*        curAssertion,
                                        GenTreeLclVarCommon* tree,
                                        Statement* stmt DEBUGARG(AssertionIndex index));
  
      // Assertion propagation functions.
      GenTree* optAssertionProp(ASSERT_VALARG_TP assertions, GenTree* tree, Statement* stmt, BasicBlock* block);
      GenTree* optAssertionProp_LclVar(ASSERT_VALARG_TP assertions, GenTreeLclVarCommon* tree, Statement* stmt);
      GenTree* optAssertionProp_Ind(ASSERT_VALARG_TP assertions, GenTree* tree, Statement* stmt);
      GenTree* optAssertionProp_Cast(ASSERT_VALARG_TP assertions, GenTreeCast* cast, Statement* stmt);
      GenTree* optAssertionProp_Call(ASSERT_VALARG_TP assertions, GenTreeCall* call, Statement* stmt);
      GenTree* optAssertionProp_RelOp(ASSERT_VALARG_TP assertions, GenTree* tree, Statement* stmt);
      GenTree* optAssertionProp_Comma(ASSERT_VALARG_TP assertions, GenTree* tree, Statement* stmt);
      GenTree* optAssertionProp_BndsChk(ASSERT_VALARG_TP assertions, GenTree* tree, Statement* stmt);
      GenTree* optAssertionPropGlobal_RelOp(ASSERT_VALARG_TP assertions, GenTree* tree, Statement* stmt);
      GenTree* optAssertionPropLocal_RelOp(ASSERT_VALARG_TP assertions, GenTree* tree, Statement* stmt);
      GenTree* optAssertionProp_Update(GenTree* newTree, GenTree* tree, Statement* stmt);
      GenTree* optNonNullAssertionProp_Call(ASSERT_VALARG_TP assertions, GenTreeCall* call);
  
      // Implied assertion functions.
      void optImpliedAssertions(AssertionIndex assertionIndex, ASSERT_TP& activeAssertions);
      void optImpliedByTypeOfAssertions(ASSERT_TP& activeAssertions);
      void optImpliedByCopyAssertion(AssertionDsc* copyAssertion, AssertionDsc* depAssertion, ASSERT_TP& result);
      void optImpliedByConstAssertion(AssertionDsc* curAssertion, ASSERT_TP& result);
  
  #ifdef DEBUG
      void optPrintAssertion(AssertionDsc* newAssertion, AssertionIndex assertionIndex = 0);
      void optPrintAssertionIndex(AssertionIndex index);
      void optPrintAssertionIndices(ASSERT_TP assertions);
      void optDebugCheckAssertion(AssertionDsc* assertion);
      void optDebugCheckAssertions(AssertionIndex AssertionIndex);
  #endif
  
      static void optDumpAssertionIndices(const char* header, ASSERT_TP assertions, const char* footer = nullptr);
      static void optDumpAssertionIndices(ASSERT_TP assertions, const char* footer = nullptr);
  
      void optAddCopies();
  
      /**************************************************************************
       *                          Range checks
       *************************************************************************/
  
  public:
      struct LoopCloneVisitorInfo
      {
          LoopCloneContext* context;
          unsigned          loopNum;
          Statement*        stmt;
          LoopCloneVisitorInfo(LoopCloneContext* context, unsigned loopNum, Statement* stmt)
              : context(context), loopNum(loopNum), stmt(nullptr)
          {
          }
      };
  
      bool optIsStackLocalInvariant(unsigned loopNum, unsigned lclNum);
      bool optExtractArrIndex(GenTree* tree, ArrIndex* result, unsigned lhsNum);
      bool optReconstructArrIndex(GenTree* tree, ArrIndex* result, unsigned lhsNum);
      bool optIdentifyLoopOptInfo(unsigned loopNum, LoopCloneContext* context);
      static fgWalkPreFn optCanOptimizeByLoopCloningVisitor;
      fgWalkResult optCanOptimizeByLoopCloning(GenTree* tree, LoopCloneVisitorInfo* info);
      bool optObtainLoopCloningOpts(LoopCloneContext* context);
      bool optIsLoopClonable(unsigned loopInd);
  
      bool optLoopCloningEnabled();
  
  #ifdef DEBUG
      void optDebugLogLoopCloning(BasicBlock* block, Statement* insertBefore);
  #endif
      void optPerformStaticOptimizations(unsigned loopNum, LoopCloneContext* context DEBUGARG(bool fastPath));
      bool optComputeDerefConditions(unsigned loopNum, LoopCloneContext* context);
      bool optDeriveLoopCloningConditions(unsigned loopNum, LoopCloneContext* context);
      BasicBlock* optInsertLoopChoiceConditions(LoopCloneContext* context,
                                                unsigned          loopNum,
                                                BasicBlock*       slowHead,
                                                BasicBlock*       insertAfter);
  
  protected:
      ssize_t optGetArrayRefScaleAndIndex(GenTree* mul, GenTree** pIndex DEBUGARG(bool bRngChk));
  
      bool optReachWithoutCall(BasicBlock* srcBB, BasicBlock* dstBB);
  
  protected:
      bool optLoopsMarked;
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           RegAlloc                                        XX
      XX                                                                           XX
      XX  Does the register allocation and puts the remaining lclVars on the stack XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      regNumber raUpdateRegStateForArg(RegState* regState, LclVarDsc* argDsc);
  
      void raMarkStkVars();
  
  #if FEATURE_PARTIAL_SIMD_CALLEE_SAVE
  #if defined(TARGET_AMD64)
      static bool varTypeNeedsPartialCalleeSave(var_types type)
      {
          assert(type != TYP_STRUCT);
          return (type == TYP_SIMD32);
      }
  #elif defined(TARGET_ARM64)
      static bool varTypeNeedsPartialCalleeSave(var_types type)
      {
          assert(type != TYP_STRUCT);
          // ARM64 ABI FP Callee save registers only require Callee to save lower 8 Bytes
          // For SIMD types longer than 8 bytes Caller is responsible for saving and restoring Upper bytes.
          return ((type == TYP_SIMD16) || (type == TYP_SIMD12));
      }
  #else // !defined(TARGET_AMD64) && !defined(TARGET_ARM64)
  #error("Unknown target architecture for FEATURE_SIMD")
  #endif // !defined(TARGET_AMD64) && !defined(TARGET_ARM64)
  #endif // FEATURE_PARTIAL_SIMD_CALLEE_SAVE
  
  protected:
      // Some things are used by both LSRA and regpredict allocators.
  
      FrameType rpFrameType;
      bool      rpMustCreateEBPCalled; // Set to true after we have called rpMustCreateEBPFrame once
  
      bool rpMustCreateEBPFrame(INDEBUG(const char** wbReason));
  
  private:
      Lowering*            m_pLowering;   // Lowering; needed to Lower IR that's added or modified after Lowering.
      LinearScanInterface* m_pLinearScan; // Linear Scan allocator
  
      /* raIsVarargsStackArg is called by raMaskStkVars and by
         lvaComputeRefCounts.  It identifies the special case
         where a varargs function has a parameter passed on the
         stack, other than the special varargs handle.  Such parameters
         require special treatment, because they cannot be tracked
         by the GC (their offsets in the stack are not known
         at compile time).
      */
  
      bool raIsVarargsStackArg(unsigned lclNum)
      {
  #ifdef TARGET_X86
  
          LclVarDsc* varDsc = lvaGetDesc(lclNum);
  
          assert(varDsc->lvIsParam);
  
          return (info.compIsVarArgs && !varDsc->lvIsRegArg && (lclNum != lvaVarargsHandleArg));
  
  #else // TARGET_X86
  
          return false;
  
  #endif // TARGET_X86
      }
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           EEInterface                                     XX
      XX                                                                           XX
      XX   Get to the class and method info from the Execution Engine given        XX
      XX   tokens for the class and method                                         XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      // Get handles
  
      void eeGetCallInfo(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                         CORINFO_RESOLVED_TOKEN* pConstrainedToken,
                         CORINFO_CALLINFO_FLAGS  flags,
                         CORINFO_CALL_INFO*      pResult);
  
      void eeGetFieldInfo(CORINFO_RESOLVED_TOKEN* pResolvedToken,
                          CORINFO_ACCESS_FLAGS    flags,
                          CORINFO_FIELD_INFO*     pResult);
  
      // Get the flags
  
      bool eeIsValueClass(CORINFO_CLASS_HANDLE clsHnd);
      bool eeIsIntrinsic(CORINFO_METHOD_HANDLE ftn);
      bool eeIsFieldStatic(CORINFO_FIELD_HANDLE fldHnd);
  
      var_types eeGetFieldType(CORINFO_FIELD_HANDLE fldHnd, CORINFO_CLASS_HANDLE* pStructHnd = nullptr);
  
  #if defined(DEBUG) || defined(FEATURE_JIT_METHOD_PERF) || defined(FEATURE_SIMD) || defined(TRACK_LSRA_STATS)
  
      const char* eeGetMethodName(CORINFO_METHOD_HANDLE hnd, const char** className);
      const char* eeGetMethodFullName(CORINFO_METHOD_HANDLE hnd);
      unsigned compMethodHash(CORINFO_METHOD_HANDLE methodHandle);
  
      bool eeIsNativeMethod(CORINFO_METHOD_HANDLE method);
      CORINFO_METHOD_HANDLE eeGetMethodHandleForNative(CORINFO_METHOD_HANDLE method);
  #endif
  
      var_types eeGetArgType(CORINFO_ARG_LIST_HANDLE list, CORINFO_SIG_INFO* sig);
      var_types eeGetArgType(CORINFO_ARG_LIST_HANDLE list, CORINFO_SIG_INFO* sig, bool* isPinned);
      CORINFO_CLASS_HANDLE eeGetArgClass(CORINFO_SIG_INFO* sig, CORINFO_ARG_LIST_HANDLE list);
      CORINFO_CLASS_HANDLE eeGetClassFromContext(CORINFO_CONTEXT_HANDLE context);
      unsigned eeGetArgSize(CORINFO_ARG_LIST_HANDLE list, CORINFO_SIG_INFO* sig);
      static unsigned eeGetArgAlignment(var_types type, bool isFloatHfa);
  
      // VOM info, method sigs
  
      void eeGetSig(unsigned               sigTok,
                    CORINFO_MODULE_HANDLE  scope,
                    CORINFO_CONTEXT_HANDLE context,
                    CORINFO_SIG_INFO*      retSig);
  
      void eeGetCallSiteSig(unsigned               sigTok,
                            CORINFO_MODULE_HANDLE  scope,
                            CORINFO_CONTEXT_HANDLE context,
                            CORINFO_SIG_INFO*      retSig);
  
      void eeGetMethodSig(CORINFO_METHOD_HANDLE methHnd, CORINFO_SIG_INFO* retSig, CORINFO_CLASS_HANDLE owner = nullptr);
  
      // Method entry-points, instrs
  
      CORINFO_METHOD_HANDLE eeMarkNativeTarget(CORINFO_METHOD_HANDLE method);
  
      CORINFO_EE_INFO eeInfo;
      bool            eeInfoInitialized;
  
      CORINFO_EE_INFO* eeGetEEInfo();
  
      // Gets the offset of a SDArray's first element
      static unsigned eeGetArrayDataOffset();
  
      // Get the offset of a MDArray's first element
      static unsigned eeGetMDArrayDataOffset(unsigned rank);
  
      // Get the offset of a MDArray's dimension length for a given dimension.
      static unsigned eeGetMDArrayLengthOffset(unsigned rank, unsigned dimension);
  
      // Get the offset of a MDArray's lower bound for a given dimension.
      static unsigned eeGetMDArrayLowerBoundOffset(unsigned rank, unsigned dimension);
  
      GenTree* eeGetPInvokeCookie(CORINFO_SIG_INFO* szMetaSig);
  
      // Returns the page size for the target machine as reported by the EE.
      target_size_t eeGetPageSize()
      {
          return (target_size_t)eeGetEEInfo()->osPageSize;
      }
  
      //------------------------------------------------------------------------
      // VirtualStubParam: virtual stub dispatch extra parameter (slot address).
      //
      // It represents Abi and target specific registers for the parameter.
      //
      class VirtualStubParamInfo
      {
      public:
          VirtualStubParamInfo(bool isCoreRTABI)
          {
  #if defined(TARGET_X86)
              reg     = REG_EAX;
              regMask = RBM_EAX;
  #elif defined(TARGET_AMD64)
              if (isCoreRTABI)
              {
                  reg     = REG_R10;
                  regMask = RBM_R10;
              }
              else
              {
                  reg     = REG_R11;
                  regMask = RBM_R11;
              }
  #elif defined(TARGET_ARM)
              if (isCoreRTABI)
              {
                  reg     = REG_R12;
                  regMask = RBM_R12;
              }
              else
              {
                  reg     = REG_R4;
                  regMask = RBM_R4;
              }
  #elif defined(TARGET_ARM64)
              reg     = REG_R11;
              regMask = RBM_R11;
  #else
  #error Unsupported or unset target architecture
  #endif
          }
  
          regNumber GetReg() const
          {
              return reg;
          }
  
          _regMask_enum GetRegMask() const
          {
              return regMask;
          }
  
      private:
          regNumber     reg;
          _regMask_enum regMask;
      };
  
      VirtualStubParamInfo* virtualStubParamInfo;
  
      bool IsTargetAbi(CORINFO_RUNTIME_ABI abi)
      {
          return eeGetEEInfo()->targetAbi == abi;
      }
  
      bool generateCFIUnwindCodes()
      {
  #if defined(FEATURE_CFI_SUPPORT)
          return TargetOS::IsUnix && IsTargetAbi(CORINFO_CORERT_ABI);
  #else
          return false;
  #endif
      }
  
      // Debugging support - Line number info
  
      void eeGetStmtOffsets();
  
      unsigned eeBoundariesCount;
  
      ICorDebugInfo::OffsetMapping* eeBoundaries; // Boundaries to report to the EE
      void eeSetLIcount(unsigned count);
      void eeSetLIinfo(unsigned which, UNATIVE_OFFSET offs, IPmappingDscKind kind, const ILLocation& loc);
      void eeSetLIdone();
  
  #ifdef DEBUG
      static void eeDispILOffs(IL_OFFSET offs);
      static void eeDispSourceMappingOffs(uint32_t offs);
      static void eeDispLineInfo(const ICorDebugInfo::OffsetMapping* line);
      void eeDispLineInfos();
  #endif // DEBUG
  
      // Debugging support - Local var info
  
      void eeGetVars();
  
      unsigned eeVarsCount;
  
      struct VarResultInfo
      {
          UNATIVE_OFFSET             startOffset;
          UNATIVE_OFFSET             endOffset;
          DWORD                      varNumber;
          CodeGenInterface::siVarLoc loc;
      } * eeVars;
      void eeSetLVcount(unsigned count);
      void eeSetLVinfo(unsigned                          which,
                       UNATIVE_OFFSET                    startOffs,
                       UNATIVE_OFFSET                    length,
                       unsigned                          varNum,
                       const CodeGenInterface::siVarLoc& loc);
      void eeSetLVdone();
  
  #ifdef DEBUG
      void eeDispVar(ICorDebugInfo::NativeVarInfo* var);
      void eeDispVars(CORINFO_METHOD_HANDLE ftn, ULONG32 cVars, ICorDebugInfo::NativeVarInfo* vars);
  #endif // DEBUG
  
      // ICorJitInfo wrappers
  
      void eeReserveUnwindInfo(bool isFunclet, bool isColdCode, ULONG unwindSize);
  
      void eeAllocUnwindInfo(BYTE*          pHotCode,
                             BYTE*          pColdCode,
                             ULONG          startOffset,
                             ULONG          endOffset,
                             ULONG          unwindSize,
                             BYTE*          pUnwindBlock,
                             CorJitFuncKind funcKind);
  
      void eeSetEHcount(unsigned cEH);
  
      void eeSetEHinfo(unsigned EHnumber, const CORINFO_EH_CLAUSE* clause);
  
      WORD eeGetRelocTypeHint(void* target);
  
      // ICorStaticInfo wrapper functions
  
      bool eeTryResolveToken(CORINFO_RESOLVED_TOKEN* resolvedToken);
  
  #if defined(UNIX_AMD64_ABI)
  #ifdef DEBUG
      static void dumpSystemVClassificationType(SystemVClassificationType ct);
  #endif // DEBUG
  
      void eeGetSystemVAmd64PassStructInRegisterDescriptor(
          /*IN*/ CORINFO_CLASS_HANDLE                                  structHnd,
          /*OUT*/ SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR* structPassInRegDescPtr);
  #endif // UNIX_AMD64_ABI
  
      template <typename ParamType>
      bool eeRunWithErrorTrap(void (*function)(ParamType*), ParamType* param)
      {
          return eeRunWithErrorTrapImp(reinterpret_cast<void (*)(void*)>(function), reinterpret_cast<void*>(param));
      }
  
      bool eeRunWithErrorTrapImp(void (*function)(void*), void* param);
  
      template <typename ParamType>
      bool eeRunWithSPMIErrorTrap(void (*function)(ParamType*), ParamType* param)
      {
          return eeRunWithSPMIErrorTrapImp(reinterpret_cast<void (*)(void*)>(function), reinterpret_cast<void*>(param));
      }
  
      bool eeRunWithSPMIErrorTrapImp(void (*function)(void*), void* param);
  
      // Utility functions
  
      const char* eeGetFieldName(CORINFO_FIELD_HANDLE fieldHnd, const char** classNamePtr = nullptr);
  
  #if defined(DEBUG)
      const WCHAR* eeGetCPString(size_t stringHandle);
  #endif
  
      const char* eeGetClassName(CORINFO_CLASS_HANDLE clsHnd);
  
      static CORINFO_METHOD_HANDLE eeFindHelper(unsigned helper);
      static CorInfoHelpFunc eeGetHelperNum(CORINFO_METHOD_HANDLE method);
  
      static bool IsSharedStaticHelper(GenTree* tree);
      static bool IsGcSafePoint(GenTreeCall* call);
  
      static CORINFO_FIELD_HANDLE eeFindJitDataOffs(unsigned jitDataOffs);
      // returns true/false if 'field' is a Jit Data offset
      static bool eeIsJitDataOffs(CORINFO_FIELD_HANDLE field);
      // returns a number < 0 if 'field' is not a Jit Data offset, otherwise the data offset (limited to 2GB)
      static int eeGetJitDataOffs(CORINFO_FIELD_HANDLE field);
  
      /*****************************************************************************/
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           CodeGenerator                                   XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      CodeGenInterface* codeGen;
  
      // Record the instr offset mapping to the generated code
  
      jitstd::list<IPmappingDsc> genIPmappings;
  
  #ifdef DEBUG
      jitstd::list<PreciseIPMapping> genPreciseIPmappings;
  #endif
  
      // Managed RetVal - A side hash table meant to record the mapping from a
      // GT_CALL node to its debug info.  This info is used to emit sequence points
      // that can be used by debugger to determine the native offset at which the
      // managed RetVal will be available.
      //
      // In fact we can store debug info in a GT_CALL node.  This was ruled out in
      // favor of a side table for two reasons: 1) We need debug info for only those
      // GT_CALL nodes (created during importation) that correspond to an IL call and
      // whose return type is other than TYP_VOID. 2) GT_CALL node is a frequently used
      // structure and IL offset is needed only when generating debuggable code. Therefore
      // it is desirable to avoid memory size penalty in retail scenarios.
      typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, DebugInfo> CallSiteDebugInfoTable;
      CallSiteDebugInfoTable* genCallSite2DebugInfoMap;
  
      unsigned    genReturnLocal; // Local number for the return value when applicable.
      BasicBlock* genReturnBB;    // jumped to when not optimizing for speed.
  
      // The following properties are part of CodeGenContext.  Getters are provided here for
      // convenience and backward compatibility, but the properties can only be set by invoking
      // the setter on CodeGenContext directly.
  
      emitter* GetEmitter() const
      {
          return codeGen->GetEmitter();
      }
  
      bool isFramePointerUsed() const
      {
          return codeGen->isFramePointerUsed();
      }
  
      bool GetInterruptible()
      {
          return codeGen->GetInterruptible();
      }
      void SetInterruptible(bool value)
      {
          codeGen->SetInterruptible(value);
      }
  
  #ifdef TARGET_ARMARCH
  
      bool GetHasTailCalls()
      {
          return codeGen->GetHasTailCalls();
      }
      void SetHasTailCalls(bool value)
      {
          codeGen->SetHasTailCalls(value);
      }
  #endif // TARGET_ARMARCH
  
  #if DOUBLE_ALIGN
      const bool genDoubleAlign()
      {
          return codeGen->doDoubleAlign();
      }
      DWORD getCanDoubleAlign();
      bool shouldDoubleAlign(unsigned refCntStk,
                             unsigned refCntReg,
                             weight_t refCntWtdReg,
                             unsigned refCntStkParam,
                             weight_t refCntWtdStkDbl);
  #endif // DOUBLE_ALIGN
  
      bool IsFullPtrRegMapRequired()
      {
          return codeGen->IsFullPtrRegMapRequired();
      }
      void SetFullPtrRegMapRequired(bool value)
      {
          codeGen->SetFullPtrRegMapRequired(value);
      }
  
  // Things that MAY belong either in CodeGen or CodeGenContext
  
  #if defined(FEATURE_EH_FUNCLETS)
      FuncInfoDsc*   compFuncInfos;
      unsigned short compCurrFuncIdx;
      unsigned short compFuncInfoCount;
  
      unsigned short compFuncCount()
      {
          assert(fgFuncletsCreated);
          return compFuncInfoCount;
      }
  
  #else // !FEATURE_EH_FUNCLETS
  
      // This is a no-op when there are no funclets!
      void genUpdateCurrentFunclet(BasicBlock* block)
      {
          return;
      }
  
      FuncInfoDsc compFuncInfoRoot;
  
      static const unsigned compCurrFuncIdx = 0;
  
      unsigned short compFuncCount()
      {
          return 1;
      }
  
  #endif // !FEATURE_EH_FUNCLETS
  
      FuncInfoDsc* funCurrentFunc();
      void funSetCurrentFunc(unsigned funcIdx);
      FuncInfoDsc* funGetFunc(unsigned funcIdx);
      unsigned int funGetFuncIdx(BasicBlock* block);
  
      // LIVENESS
  
      VARSET_TP compCurLife;     // current live variables
      GenTree*  compCurLifeTree; // node after which compCurLife has been computed
  
      // Compare the given "newLife" with last set of live variables and update
      // codeGen "gcInfo", siScopes, "regSet" with the new variable's homes/liveness.
      template <bool ForCodeGen>
      void compChangeLife(VARSET_VALARG_TP newLife);
  
      // Update the GC's masks, register's masks and reports change on variable's homes given a set of
      // current live variables if changes have happened since "compCurLife".
      template <bool ForCodeGen>
      inline void compUpdateLife(VARSET_VALARG_TP newLife);
  
      // Gets a register mask that represent the kill set for a helper call since
      // not all JIT Helper calls follow the standard ABI on the target architecture.
      regMaskTP compHelperCallKillSet(CorInfoHelpFunc helper);
  
  #ifdef TARGET_ARM
      // Requires that "varDsc" be a promoted struct local variable being passed as an argument, beginning at
      // "firstArgRegNum", which is assumed to have already been aligned to the register alignment restriction of the
      // struct type. Adds bits to "*pArgSkippedRegMask" for any argument registers *not* used in passing "varDsc" --
      // i.e., internal "holes" caused by internal alignment constraints.  For example, if the struct contained an int and
      // a double, and we at R0 (on ARM), then R1 would be skipped, and the bit for R1 would be added to the mask.
      void fgAddSkippedRegsInPromotedStructArg(LclVarDsc* varDsc, unsigned firstArgRegNum, regMaskTP* pArgSkippedRegMask);
  #endif // TARGET_ARM
  
      // If "tree" is a indirection (GT_IND, or GT_OBJ) whose arg is an ADDR, whose arg is a LCL_VAR, return that LCL_VAR
      // node, else NULL.
      static GenTreeLclVar* fgIsIndirOfAddrOfLocal(GenTree* tree);
  
      // This map is indexed by GT_OBJ nodes that are address of promoted struct variables, which
      // have been annotated with the GTF_VAR_DEATH flag.  If such a node is *not* mapped in this
      // table, one may assume that all the (tracked) field vars die at this GT_OBJ.  Otherwise,
      // the node maps to a pointer to a VARSET_TP, containing set bits for each of the tracked field
      // vars of the promoted struct local that go dead at the given node (the set bits are the bits
      // for the tracked var indices of the field vars, as in a live var set).
      //
      // The map is allocated on demand so all map operations should use one of the following three
      // wrapper methods.
  
      NodeToVarsetPtrMap* m_promotedStructDeathVars;
  
      NodeToVarsetPtrMap* GetPromotedStructDeathVars()
      {
          if (m_promotedStructDeathVars == nullptr)
          {
              m_promotedStructDeathVars = new (getAllocator()) NodeToVarsetPtrMap(getAllocator());
          }
          return m_promotedStructDeathVars;
      }
  
      void ClearPromotedStructDeathVars()
      {
          if (m_promotedStructDeathVars != nullptr)
          {
              m_promotedStructDeathVars->RemoveAll();
          }
      }
  
      bool LookupPromotedStructDeathVars(GenTree* tree, VARSET_TP** bits)
      {
          *bits       = nullptr;
          bool result = false;
  
          if (m_promotedStructDeathVars != nullptr)
          {
              result = m_promotedStructDeathVars->Lookup(tree, bits);
          }
  
          return result;
      }
  
  /*
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XX                                                                           XX
  XX                           UnwindInfo                                      XX
  XX                                                                           XX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  */
  
  #if !defined(__GNUC__)
  #pragma region Unwind information
  #endif
  
  public:
      //
      // Infrastructure functions: start/stop/reserve/emit.
      //
  
      void unwindBegProlog();
      void unwindEndProlog();
      void unwindBegEpilog();
      void unwindEndEpilog();
      void unwindReserve();
      void unwindEmit(void* pHotCode, void* pColdCode);
  
      //
      // Specific unwind information functions: called by code generation to indicate a particular
      // prolog or epilog unwindable instruction has been generated.
      //
  
      void unwindPush(regNumber reg);
      void unwindAllocStack(unsigned size);
      void unwindSetFrameReg(regNumber reg, unsigned offset);
      void unwindSaveReg(regNumber reg, unsigned offset);
  
  #if defined(TARGET_ARM)
      void unwindPushMaskInt(regMaskTP mask);
      void unwindPushMaskFloat(regMaskTP mask);
      void unwindPopMaskInt(regMaskTP mask);
      void unwindPopMaskFloat(regMaskTP mask);
      void unwindBranch16();                    // The epilog terminates with a 16-bit branch (e.g., "bx lr")
      void unwindNop(unsigned codeSizeInBytes); // Generate unwind NOP code. 'codeSizeInBytes' is 2 or 4 bytes. Only
                                                // called via unwindPadding().
      void unwindPadding(); // Generate a sequence of unwind NOP codes representing instructions between the last
                            // instruction and the current location.
  #endif                    // TARGET_ARM
  
  #if defined(TARGET_ARM64)
      void unwindNop();
      void unwindPadding(); // Generate a sequence of unwind NOP codes representing instructions between the last
                            // instruction and the current location.
      void unwindSaveReg(regNumber reg, int offset);                                // str reg, [sp, #offset]
      void unwindSaveRegPreindexed(regNumber reg, int offset);                      // str reg, [sp, #offset]!
      void unwindSaveRegPair(regNumber reg1, regNumber reg2, int offset);           // stp reg1, reg2, [sp, #offset]
      void unwindSaveRegPairPreindexed(regNumber reg1, regNumber reg2, int offset); // stp reg1, reg2, [sp, #offset]!
      void unwindSaveNext();                                                        // unwind code: save_next
      void unwindReturn(regNumber reg);                                             // ret lr
  #endif                                                                            // defined(TARGET_ARM64)
  
      //
      // Private "helper" functions for the unwind implementation.
      //
  
  private:
  #if defined(FEATURE_EH_FUNCLETS)
      void unwindGetFuncLocations(FuncInfoDsc*             func,
                                  bool                     getHotSectionData,
                                  /* OUT */ emitLocation** ppStartLoc,
                                  /* OUT */ emitLocation** ppEndLoc);
  #endif // FEATURE_EH_FUNCLETS
  
      void unwindReserveFunc(FuncInfoDsc* func);
      void unwindEmitFunc(FuncInfoDsc* func, void* pHotCode, void* pColdCode);
  
  #if defined(TARGET_AMD64) || (defined(TARGET_X86) && defined(FEATURE_EH_FUNCLETS))
  
      void unwindReserveFuncHelper(FuncInfoDsc* func, bool isHotCode);
      void unwindEmitFuncHelper(FuncInfoDsc* func, void* pHotCode, void* pColdCode, bool isHotCode);
  
  #endif // TARGET_AMD64 || (TARGET_X86 && FEATURE_EH_FUNCLETS)
  
      UNATIVE_OFFSET unwindGetCurrentOffset(FuncInfoDsc* func);
  
  #if defined(TARGET_AMD64)
  
      void unwindBegPrologWindows();
      void unwindPushWindows(regNumber reg);
      void unwindAllocStackWindows(unsigned size);
      void unwindSetFrameRegWindows(regNumber reg, unsigned offset);
      void unwindSaveRegWindows(regNumber reg, unsigned offset);
  
  #ifdef UNIX_AMD64_ABI
      void unwindSaveRegCFI(regNumber reg, unsigned offset);
  #endif // UNIX_AMD64_ABI
  #elif defined(TARGET_ARM)
  
      void unwindPushPopMaskInt(regMaskTP mask, bool useOpsize16);
      void unwindPushPopMaskFloat(regMaskTP mask);
  
  #endif // TARGET_ARM
  
  #if defined(FEATURE_CFI_SUPPORT)
      short mapRegNumToDwarfReg(regNumber reg);
      void createCfiCode(FuncInfoDsc* func, UNATIVE_OFFSET codeOffset, UCHAR opcode, short dwarfReg, INT offset = 0);
      void unwindPushPopCFI(regNumber reg);
      void unwindBegPrologCFI();
      void unwindPushPopMaskCFI(regMaskTP regMask, bool isFloat);
      void unwindAllocStackCFI(unsigned size);
      void unwindSetFrameRegCFI(regNumber reg, unsigned offset);
      void unwindEmitFuncCFI(FuncInfoDsc* func, void* pHotCode, void* pColdCode);
  #ifdef DEBUG
      void DumpCfiInfo(bool                  isHotCode,
                       UNATIVE_OFFSET        startOffset,
                       UNATIVE_OFFSET        endOffset,
                       DWORD                 cfiCodeBytes,
                       const CFI_CODE* const pCfiCode);
  #endif
  
  #endif // FEATURE_CFI_SUPPORT
  
  #if !defined(__GNUC__)
  #pragma endregion // Note: region is NOT under !defined(__GNUC__)
  #endif
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                               SIMD                                        XX
      XX                                                                           XX
      XX   Info about SIMD types, methods and the SIMD assembly (i.e. the assembly XX
      XX   that contains the distinguished, well-known SIMD type definitions).     XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
      bool IsBaselineSimdIsaSupported()
      {
  #ifdef FEATURE_SIMD
  #if defined(TARGET_XARCH)
          CORINFO_InstructionSet minimumIsa = InstructionSet_SSE2;
  #elif defined(TARGET_ARM64)
          CORINFO_InstructionSet minimumIsa = InstructionSet_AdvSimd;
  #else
  #error Unsupported platform
  #endif // !TARGET_XARCH && !TARGET_ARM64
  
          return compOpportunisticallyDependsOn(minimumIsa);
  #else
          return false;
  #endif
      }
  
  #if defined(DEBUG)
      bool IsBaselineSimdIsaSupportedDebugOnly()
      {
  #ifdef FEATURE_SIMD
  #if defined(TARGET_XARCH)
          CORINFO_InstructionSet minimumIsa = InstructionSet_SSE2;
  #elif defined(TARGET_ARM64)
          CORINFO_InstructionSet minimumIsa = InstructionSet_AdvSimd;
  #else
  #error Unsupported platform
  #endif // !TARGET_XARCH && !TARGET_ARM64
  
          return compIsaSupportedDebugOnly(minimumIsa);
  #else
          return false;
  #endif // FEATURE_SIMD
      }
  #endif // DEBUG
  
      // Get highest available level for SIMD codegen
      SIMDLevel getSIMDSupportLevel()
      {
  #if defined(TARGET_XARCH)
          if (compOpportunisticallyDependsOn(InstructionSet_AVX2))
          {
              return SIMD_AVX2_Supported;
          }
  
          if (compOpportunisticallyDependsOn(InstructionSet_SSE42))
          {
              return SIMD_SSE4_Supported;
          }
  
          // min bar is SSE2
          return SIMD_SSE2_Supported;
  #else
          assert(!"Available instruction set(s) for SIMD codegen is not defined for target arch");
          unreached();
          return SIMD_Not_Supported;
  #endif
      }
  
      bool isIntrinsicType(CORINFO_CLASS_HANDLE clsHnd)
      {
          return info.compCompHnd->isIntrinsicType(clsHnd);
      }
  
      const char* getClassNameFromMetadata(CORINFO_CLASS_HANDLE cls, const char** namespaceName)
      {
          return info.compCompHnd->getClassNameFromMetadata(cls, namespaceName);
      }
  
      CORINFO_CLASS_HANDLE getTypeInstantiationArgument(CORINFO_CLASS_HANDLE cls, unsigned index)
      {
          return info.compCompHnd->getTypeInstantiationArgument(cls, index);
      }
  
  #ifdef FEATURE_SIMD
  
      // Should we support SIMD intrinsics?
      bool featureSIMD;
  
      // Should we recognize SIMD types?
      // We always do this on ARM64 to support HVA types.
      bool supportSIMDTypes()
      {
  #ifdef TARGET_ARM64
          return true;
  #else
          return featureSIMD;
  #endif
      }
  
      // Have we identified any SIMD types?
      // This is currently used by struct promotion to avoid getting type information for a struct
      // field to see if it is a SIMD type, if we haven't seen any SIMD types or operations in
      // the method.
      bool _usesSIMDTypes;
      bool usesSIMDTypes()
      {
          return _usesSIMDTypes;
      }
      void setUsesSIMDTypes(bool value)
      {
          _usesSIMDTypes = value;
      }
  
      // This is a temp lclVar allocated on the stack as TYP_SIMD.  It is used to implement intrinsics
      // that require indexed access to the individual fields of the vector, which is not well supported
      // by the hardware.  It is allocated when/if such situations are encountered during Lowering.
      unsigned lvaSIMDInitTempVarNum;
  
      struct SIMDHandlesCache
      {
          // SIMD Types
          CORINFO_CLASS_HANDLE SIMDFloatHandle;
          CORINFO_CLASS_HANDLE SIMDDoubleHandle;
          CORINFO_CLASS_HANDLE SIMDIntHandle;
          CORINFO_CLASS_HANDLE SIMDUShortHandle;
          CORINFO_CLASS_HANDLE SIMDUByteHandle;
          CORINFO_CLASS_HANDLE SIMDShortHandle;
          CORINFO_CLASS_HANDLE SIMDByteHandle;
          CORINFO_CLASS_HANDLE SIMDLongHandle;
          CORINFO_CLASS_HANDLE SIMDUIntHandle;
          CORINFO_CLASS_HANDLE SIMDULongHandle;
          CORINFO_CLASS_HANDLE SIMDNIntHandle;
          CORINFO_CLASS_HANDLE SIMDNUIntHandle;
  
          CORINFO_CLASS_HANDLE SIMDVector2Handle;
          CORINFO_CLASS_HANDLE SIMDVector3Handle;
          CORINFO_CLASS_HANDLE SIMDVector4Handle;
          CORINFO_CLASS_HANDLE SIMDVectorHandle;
  
  #ifdef FEATURE_HW_INTRINSICS
  #if defined(TARGET_ARM64)
          CORINFO_CLASS_HANDLE Vector64FloatHandle;
          CORINFO_CLASS_HANDLE Vector64DoubleHandle;
          CORINFO_CLASS_HANDLE Vector64IntHandle;
          CORINFO_CLASS_HANDLE Vector64UShortHandle;
          CORINFO_CLASS_HANDLE Vector64UByteHandle;
          CORINFO_CLASS_HANDLE Vector64ShortHandle;
          CORINFO_CLASS_HANDLE Vector64ByteHandle;
          CORINFO_CLASS_HANDLE Vector64LongHandle;
          CORINFO_CLASS_HANDLE Vector64UIntHandle;
          CORINFO_CLASS_HANDLE Vector64ULongHandle;
          CORINFO_CLASS_HANDLE Vector64NIntHandle;
          CORINFO_CLASS_HANDLE Vector64NUIntHandle;
  #endif // defined(TARGET_ARM64)
          CORINFO_CLASS_HANDLE Vector128FloatHandle;
          CORINFO_CLASS_HANDLE Vector128DoubleHandle;
          CORINFO_CLASS_HANDLE Vector128IntHandle;
          CORINFO_CLASS_HANDLE Vector128UShortHandle;
          CORINFO_CLASS_HANDLE Vector128UByteHandle;
          CORINFO_CLASS_HANDLE Vector128ShortHandle;
          CORINFO_CLASS_HANDLE Vector128ByteHandle;
          CORINFO_CLASS_HANDLE Vector128LongHandle;
          CORINFO_CLASS_HANDLE Vector128UIntHandle;
          CORINFO_CLASS_HANDLE Vector128ULongHandle;
          CORINFO_CLASS_HANDLE Vector128NIntHandle;
          CORINFO_CLASS_HANDLE Vector128NUIntHandle;
  #if defined(TARGET_XARCH)
          CORINFO_CLASS_HANDLE Vector256FloatHandle;
          CORINFO_CLASS_HANDLE Vector256DoubleHandle;
          CORINFO_CLASS_HANDLE Vector256IntHandle;
          CORINFO_CLASS_HANDLE Vector256UShortHandle;
          CORINFO_CLASS_HANDLE Vector256UByteHandle;
          CORINFO_CLASS_HANDLE Vector256ShortHandle;
          CORINFO_CLASS_HANDLE Vector256ByteHandle;
          CORINFO_CLASS_HANDLE Vector256LongHandle;
          CORINFO_CLASS_HANDLE Vector256UIntHandle;
          CORINFO_CLASS_HANDLE Vector256ULongHandle;
          CORINFO_CLASS_HANDLE Vector256NIntHandle;
          CORINFO_CLASS_HANDLE Vector256NUIntHandle;
  #endif // defined(TARGET_XARCH)
  #endif // FEATURE_HW_INTRINSICS
  
          SIMDHandlesCache()
          {
              memset(this, 0, sizeof(*this));
          }
      };
  
      SIMDHandlesCache* m_simdHandleCache;
  
      // Get an appropriate "zero" for the given type and class handle.
      GenTree* gtGetSIMDZero(var_types simdType, CorInfoType simdBaseJitType, CORINFO_CLASS_HANDLE simdHandle);
  
      // Get the handle for a SIMD type.
      CORINFO_CLASS_HANDLE gtGetStructHandleForSIMD(var_types simdType, CorInfoType simdBaseJitType)
      {
          if (m_simdHandleCache == nullptr)
          {
              // This may happen if the JIT generates SIMD node on its own, without importing them.
              // Otherwise getBaseJitTypeAndSizeOfSIMDType should have created the cache.
              return NO_CLASS_HANDLE;
          }
  
          if (simdBaseJitType == CORINFO_TYPE_FLOAT)
          {
              switch (simdType)
              {
                  case TYP_SIMD8:
                      return m_simdHandleCache->SIMDVector2Handle;
                  case TYP_SIMD12:
                      return m_simdHandleCache->SIMDVector3Handle;
                  case TYP_SIMD16:
                      if ((getSIMDVectorType() == TYP_SIMD32) ||
                          (m_simdHandleCache->SIMDVector4Handle != NO_CLASS_HANDLE))
                      {
                          return m_simdHandleCache->SIMDVector4Handle;
                      }
                      break;
                  case TYP_SIMD32:
                      break;
                  default:
                      unreached();
              }
          }
          assert(emitTypeSize(simdType) <= largestEnregisterableStructSize());
          switch (simdBaseJitType)
          {
              case CORINFO_TYPE_FLOAT:
                  return m_simdHandleCache->SIMDFloatHandle;
              case CORINFO_TYPE_DOUBLE:
                  return m_simdHandleCache->SIMDDoubleHandle;
              case CORINFO_TYPE_INT:
                  return m_simdHandleCache->SIMDIntHandle;
              case CORINFO_TYPE_USHORT:
                  return m_simdHandleCache->SIMDUShortHandle;
              case CORINFO_TYPE_UBYTE:
                  return m_simdHandleCache->SIMDUByteHandle;
              case CORINFO_TYPE_SHORT:
                  return m_simdHandleCache->SIMDShortHandle;
              case CORINFO_TYPE_BYTE:
                  return m_simdHandleCache->SIMDByteHandle;
              case CORINFO_TYPE_LONG:
                  return m_simdHandleCache->SIMDLongHandle;
              case CORINFO_TYPE_UINT:
                  return m_simdHandleCache->SIMDUIntHandle;
              case CORINFO_TYPE_ULONG:
                  return m_simdHandleCache->SIMDULongHandle;
              case CORINFO_TYPE_NATIVEINT:
                  return m_simdHandleCache->SIMDNIntHandle;
              case CORINFO_TYPE_NATIVEUINT:
                  return m_simdHandleCache->SIMDNUIntHandle;
              default:
                  assert(!"Didn't find a class handle for simdType");
          }
          return NO_CLASS_HANDLE;
      }
  
      // Returns true if this is a SIMD type that should be considered an opaque
      // vector type (i.e. do not analyze or promote its fields).
      // Note that all but the fixed vector types are opaque, even though they may
      // actually be declared as having fields.
      bool isOpaqueSIMDType(CORINFO_CLASS_HANDLE structHandle) const
      {
          return ((m_simdHandleCache != nullptr) && (structHandle != m_simdHandleCache->SIMDVector2Handle) &&
                  (structHandle != m_simdHandleCache->SIMDVector3Handle) &&
                  (structHandle != m_simdHandleCache->SIMDVector4Handle));
      }
  
      // Returns true if the tree corresponds to a TYP_SIMD lcl var.
      // Note that both SIMD vector args and locals are mared as lvSIMDType = true, but
      // type of an arg node is TYP_BYREF and a local node is TYP_SIMD or TYP_STRUCT.
      bool isSIMDTypeLocal(GenTree* tree)
      {
          return tree->OperIsLocal() && lvaGetDesc(tree->AsLclVarCommon())->lvSIMDType;
      }
  
      // Returns true if the lclVar is an opaque SIMD type.
      bool isOpaqueSIMDLclVar(const LclVarDsc* varDsc) const
      {
          if (!varDsc->lvSIMDType)
          {
              return false;
          }
          return isOpaqueSIMDType(varDsc->GetStructHnd());
      }
  
      static bool isRelOpSIMDIntrinsic(SIMDIntrinsicID intrinsicId)
      {
          return (intrinsicId == SIMDIntrinsicEqual);
      }
  
      // Returns base JIT type of a TYP_SIMD local.
      // Returns CORINFO_TYPE_UNDEF if the local is not TYP_SIMD.
      CorInfoType getBaseJitTypeOfSIMDLocal(GenTree* tree)
      {
          if (isSIMDTypeLocal(tree))
          {
              return lvaGetDesc(tree->AsLclVarCommon())->GetSimdBaseJitType();
          }
  
          return CORINFO_TYPE_UNDEF;
      }
  
      bool isSIMDClass(CORINFO_CLASS_HANDLE clsHnd)
      {
          if (isIntrinsicType(clsHnd))
          {
              const char* namespaceName = nullptr;
              (void)getClassNameFromMetadata(clsHnd, &namespaceName);
              return strcmp(namespaceName, "System.Numerics") == 0;
          }
          return false;
      }
  
      bool isSIMDClass(typeInfo* pTypeInfo)
      {
          return pTypeInfo->IsStruct() && isSIMDClass(pTypeInfo->GetClassHandleForValueClass());
      }
  
      bool isHWSIMDClass(CORINFO_CLASS_HANDLE clsHnd)
      {
  #ifdef FEATURE_HW_INTRINSICS
          if (isIntrinsicType(clsHnd))
          {
              const char* namespaceName = nullptr;
              (void)getClassNameFromMetadata(clsHnd, &namespaceName);
              return strcmp(namespaceName, "System.Runtime.Intrinsics") == 0;
          }
  #endif // FEATURE_HW_INTRINSICS
          return false;
      }
  
      bool isHWSIMDClass(typeInfo* pTypeInfo)
      {
  #ifdef FEATURE_HW_INTRINSICS
          return pTypeInfo->IsStruct() && isHWSIMDClass(pTypeInfo->GetClassHandleForValueClass());
  #else
          return false;
  #endif
      }
  
      bool isSIMDorHWSIMDClass(CORINFO_CLASS_HANDLE clsHnd)
      {
          return isSIMDClass(clsHnd) || isHWSIMDClass(clsHnd);
      }
  
      bool isSIMDorHWSIMDClass(typeInfo* pTypeInfo)
      {
          return isSIMDClass(pTypeInfo) || isHWSIMDClass(pTypeInfo);
      }
  
      // Get the base (element) type and size in bytes for a SIMD type. Returns CORINFO_TYPE_UNDEF
      // if it is not a SIMD type or is an unsupported base JIT type.
      CorInfoType getBaseJitTypeAndSizeOfSIMDType(CORINFO_CLASS_HANDLE typeHnd, unsigned* sizeBytes = nullptr);
  
      CorInfoType getBaseJitTypeOfSIMDType(CORINFO_CLASS_HANDLE typeHnd)
      {
          return getBaseJitTypeAndSizeOfSIMDType(typeHnd, nullptr);
      }
  
      // Get SIMD Intrinsic info given the method handle.
      // Also sets typeHnd, argCount, baseType and sizeBytes out params.
      const SIMDIntrinsicInfo* getSIMDIntrinsicInfo(CORINFO_CLASS_HANDLE* typeHnd,
                                                    CORINFO_METHOD_HANDLE methodHnd,
                                                    CORINFO_SIG_INFO*     sig,
                                                    bool                  isNewObj,
                                                    unsigned*             argCount,
                                                    CorInfoType*          simdBaseJitType,
                                                    unsigned*             sizeBytes);
  
      // Pops and returns GenTree node from importers type stack.
      // Normalizes TYP_STRUCT value in case of GT_CALL, GT_RET_EXPR and arg nodes.
      GenTree* impSIMDPopStack(var_types type, bool expectAddr = false, CORINFO_CLASS_HANDLE structType = nullptr);
  
      // Transforms operands and returns the SIMD intrinsic to be applied on
      // transformed operands to obtain given relop result.
      SIMDIntrinsicID impSIMDRelOp(SIMDIntrinsicID      relOpIntrinsicId,
                                   CORINFO_CLASS_HANDLE typeHnd,
                                   unsigned             simdVectorSize,
                                   CorInfoType*         inOutBaseJitType,
                                   GenTree**            op1,
                                   GenTree**            op2);
  
  #if defined(TARGET_XARCH)
  
      // Transforms operands and returns the SIMD intrinsic to be applied on
      // transformed operands to obtain == comparison result.
      SIMDIntrinsicID impSIMDLongRelOpEqual(CORINFO_CLASS_HANDLE typeHnd,
                                            unsigned             simdVectorSize,
                                            GenTree**            op1,
                                            GenTree**            op2);
  
  #endif // defined(TARGET_XARCH)
  
      void setLclRelatedToSIMDIntrinsic(GenTree* tree);
      bool areFieldsContiguous(GenTree* op1, GenTree* op2);
      bool areLocalFieldsContiguous(GenTreeLclFld* first, GenTreeLclFld* second);
      bool areArrayElementsContiguous(GenTree* op1, GenTree* op2);
      bool areArgumentsContiguous(GenTree* op1, GenTree* op2);
      GenTree* createAddressNodeForSIMDInit(GenTree* tree, unsigned simdSize);
  
      // check methodHnd to see if it is a SIMD method that is expanded as an intrinsic in the JIT.
      GenTree* impSIMDIntrinsic(OPCODE                opcode,
                                GenTree*              newobjThis,
                                CORINFO_CLASS_HANDLE  clsHnd,
                                CORINFO_METHOD_HANDLE method,
                                CORINFO_SIG_INFO*     sig,
                                unsigned              methodFlags,
                                int                   memberRef);
  
      GenTree* getOp1ForConstructor(OPCODE opcode, GenTree* newobjThis, CORINFO_CLASS_HANDLE clsHnd);
  
      // Whether SIMD vector occupies part of SIMD register.
      // SSE2: vector2f/3f are considered sub register SIMD types.
      // AVX: vector2f, 3f and 4f are all considered sub register SIMD types.
      bool isSubRegisterSIMDType(GenTreeSIMD* simdNode)
      {
          unsigned vectorRegisterByteLength;
  #if defined(TARGET_XARCH)
          // Calling the getSIMDVectorRegisterByteLength api causes the size of Vector<T> to be recorded
          // with the AOT compiler, so that it cannot change from aot compilation time to runtime
          // This api does not require such fixing as it merely pertains to the size of the simd type
          // relative to the Vector<T> size as used at compile time. (So detecting a vector length of 16 here
          // does not preclude the code from being used on a machine with a larger vector length.)
          if (getSIMDSupportLevel() < SIMD_AVX2_Supported)
          {
              vectorRegisterByteLength = 16;
          }
          else
          {
              vectorRegisterByteLength = 32;
          }
  #else
          vectorRegisterByteLength = getSIMDVectorRegisterByteLength();
  #endif
          return (simdNode->GetSimdSize() < vectorRegisterByteLength);
      }
  
      // Get the type for the hardware SIMD vector.
      // This is the maximum SIMD type supported for this target.
      var_types getSIMDVectorType()
      {
  #if defined(TARGET_XARCH)
          if (getSIMDSupportLevel() == SIMD_AVX2_Supported)
          {
              return TYP_SIMD32;
          }
          else
          {
              // Verify and record that AVX2 isn't supported
              compVerifyInstructionSetUnusable(InstructionSet_AVX2);
              assert(getSIMDSupportLevel() >= SIMD_SSE2_Supported);
              return TYP_SIMD16;
          }
  #elif defined(TARGET_ARM64)
          return TYP_SIMD16;
  #else
          assert(!"getSIMDVectorType() unimplemented on target arch");
          unreached();
  #endif
      }
  
      // Get the size of the SIMD type in bytes
      int getSIMDTypeSizeInBytes(CORINFO_CLASS_HANDLE typeHnd)
      {
          unsigned sizeBytes = 0;
          (void)getBaseJitTypeAndSizeOfSIMDType(typeHnd, &sizeBytes);
          return sizeBytes;
      }
  
      // Get the the number of elements of baseType of SIMD vector given by its size and baseType
      static int getSIMDVectorLength(unsigned simdSize, var_types baseType);
  
      // Get the the number of elements of baseType of SIMD vector given by its type handle
      int getSIMDVectorLength(CORINFO_CLASS_HANDLE typeHnd);
  
      // Get preferred alignment of SIMD type.
      int getSIMDTypeAlignment(var_types simdType);
  
      // Get the number of bytes in a System.Numeric.Vector<T> for the current compilation.
      // Note - cannot be used for System.Runtime.Intrinsic
      unsigned getSIMDVectorRegisterByteLength()
      {
  #if defined(TARGET_XARCH)
          if (getSIMDSupportLevel() == SIMD_AVX2_Supported)
          {
              return YMM_REGSIZE_BYTES;
          }
          else
          {
              // Verify and record that AVX2 isn't supported
              compVerifyInstructionSetUnusable(InstructionSet_AVX2);
              assert(getSIMDSupportLevel() >= SIMD_SSE2_Supported);
              return XMM_REGSIZE_BYTES;
          }
  #elif defined(TARGET_ARM64)
          return FP_REGSIZE_BYTES;
  #else
          assert(!"getSIMDVectorRegisterByteLength() unimplemented on target arch");
          unreached();
  #endif
      }
  
      // The minimum and maximum possible number of bytes in a SIMD vector.
  
      // maxSIMDStructBytes
      // The minimum SIMD size supported by System.Numeric.Vectors or System.Runtime.Intrinsic
      // SSE:  16-byte Vector<T> and Vector128<T>
      // AVX:  32-byte Vector256<T> (Vector<T> is 16-byte)
      // AVX2: 32-byte Vector<T> and Vector256<T>
      unsigned int maxSIMDStructBytes()
      {
  #if defined(FEATURE_HW_INTRINSICS) && defined(TARGET_XARCH)
          if (compOpportunisticallyDependsOn(InstructionSet_AVX))
          {
              return YMM_REGSIZE_BYTES;
          }
          else
          {
              // Verify and record that AVX2 isn't supported
              compVerifyInstructionSetUnusable(InstructionSet_AVX2);
              assert(getSIMDSupportLevel() >= SIMD_SSE2_Supported);
              return XMM_REGSIZE_BYTES;
          }
  #else
          return getSIMDVectorRegisterByteLength();
  #endif
      }
  
      unsigned int minSIMDStructBytes()
      {
          return emitTypeSize(TYP_SIMD8);
      }
  
  public:
      // Returns the codegen type for a given SIMD size.
      static var_types getSIMDTypeForSize(unsigned size)
      {
          var_types simdType = TYP_UNDEF;
          if (size == 8)
          {
              simdType = TYP_SIMD8;
          }
          else if (size == 12)
          {
              simdType = TYP_SIMD12;
          }
          else if (size == 16)
          {
              simdType = TYP_SIMD16;
          }
          else if (size == 32)
          {
              simdType = TYP_SIMD32;
          }
          else
          {
              noway_assert(!"Unexpected size for SIMD type");
          }
          return simdType;
      }
  
  private:
      unsigned getSIMDInitTempVarNum(var_types simdType);
  
  #else  // !FEATURE_SIMD
      bool isOpaqueSIMDLclVar(LclVarDsc* varDsc)
      {
          return false;
      }
  #endif // FEATURE_SIMD
  
  public:
      //------------------------------------------------------------------------
      // largestEnregisterableStruct: The size in bytes of the largest struct that can be enregistered.
      //
      // Notes: It is not guaranteed that the struct of this size or smaller WILL be a
      //        candidate for enregistration.
  
      unsigned largestEnregisterableStructSize()
      {
  #ifdef FEATURE_SIMD
  #if defined(FEATURE_HW_INTRINSICS) && defined(TARGET_XARCH)
          if (opts.IsReadyToRun())
          {
              // Return constant instead of maxSIMDStructBytes, as maxSIMDStructBytes performs
              // checks that are effected by the current level of instruction set support would
              // otherwise cause the highest level of instruction set support to be reported to crossgen2.
              // and this api is only ever used as an optimization or assert, so no reporting should
              // ever happen.
              return YMM_REGSIZE_BYTES;
          }
  #endif // defined(FEATURE_HW_INTRINSICS) && defined(TARGET_XARCH)
          unsigned vectorRegSize = maxSIMDStructBytes();
          assert(vectorRegSize >= TARGET_POINTER_SIZE);
          return vectorRegSize;
  #else  // !FEATURE_SIMD
          return TARGET_POINTER_SIZE;
  #endif // !FEATURE_SIMD
      }
  
      // Use to determine if a struct *might* be a SIMD type. As this function only takes a size, many
      // structs will fit the criteria.
      bool structSizeMightRepresentSIMDType(size_t structSize)
      {
  #ifdef FEATURE_SIMD
          // Do not use maxSIMDStructBytes as that api in R2R on X86 and X64 may notify the JIT
          // about the size of a struct under the assumption that the struct size needs to be recorded.
          // By using largestEnregisterableStructSize here, the detail of whether or not Vector256<T> is
          // enregistered or not will not be messaged to the R2R compiler.
          return (structSize >= minSIMDStructBytes()) && (structSize <= largestEnregisterableStructSize());
  #else
          return false;
  #endif // FEATURE_SIMD
      }
  
  #ifdef FEATURE_SIMD
      static bool vnEncodesResultTypeForSIMDIntrinsic(SIMDIntrinsicID intrinsicId);
  #endif // !FEATURE_SIMD
  #ifdef FEATURE_HW_INTRINSICS
      static bool vnEncodesResultTypeForHWIntrinsic(NamedIntrinsic hwIntrinsicID);
  #endif // FEATURE_HW_INTRINSICS
  
  private:
      // These routines need not be enclosed under FEATURE_SIMD since lvIsSIMDType()
      // is defined for both FEATURE_SIMD and !FEATURE_SIMD apropriately. The use
      // of this routines also avoids the need of #ifdef FEATURE_SIMD specific code.
  
      // Is this var is of type simd struct?
      bool lclVarIsSIMDType(unsigned varNum)
      {
          return lvaGetDesc(varNum)->lvIsSIMDType();
      }
  
      // Is this Local node a SIMD local?
      bool lclVarIsSIMDType(GenTreeLclVarCommon* lclVarTree)
      {
          return lclVarIsSIMDType(lclVarTree->GetLclNum());
      }
  
      // Returns true if the TYP_SIMD locals on stack are aligned at their
      // preferred byte boundary specified by getSIMDTypeAlignment().
      //
      // As per the Intel manual, the preferred alignment for AVX vectors is
      // 32-bytes. It is not clear whether additional stack space used in
      // aligning stack is worth the benefit and for now will use 16-byte
      // alignment for AVX 256-bit vectors with unaligned load/stores to/from
      // memory. On x86, the stack frame is aligned to 4 bytes. We need to extend
      // existing support for double (8-byte) alignment to 16 or 32 byte
      // alignment for frames with local SIMD vars, if that is determined to be
      // profitable.
      //
      // On Amd64 and SysV, RSP+8 is aligned on entry to the function (before
      // prolog has run). This means that in RBP-based frames RBP will be 16-byte
      // aligned. For RSP-based frames these are only sometimes aligned, depending
      // on the frame size.
      //
      bool isSIMDTypeLocalAligned(unsigned varNum)
      {
  #if defined(FEATURE_SIMD) && ALIGN_SIMD_TYPES
          if (lclVarIsSIMDType(varNum) && lvaTable[varNum].lvType != TYP_BYREF)
          {
              // TODO-Cleanup: Can't this use the lvExactSize on the varDsc?
              int alignment = getSIMDTypeAlignment(lvaTable[varNum].lvType);
              if (alignment <= STACK_ALIGN)
              {
                  bool rbpBased;
                  int  off = lvaFrameAddress(varNum, &rbpBased);
                  // On SysV and Winx64 ABIs RSP+8 will be 16-byte aligned at the
                  // first instruction of a function. If our frame is RBP based
                  // then RBP will always be 16 bytes aligned, so we can simply
                  // check the offset.
                  if (rbpBased)
                  {
                      return (off % alignment) == 0;
                  }
  
                  // For RSP-based frame the alignment of RSP depends on our
                  // locals. rsp+8 is aligned on entry and we just subtract frame
                  // size so it is not hard to compute. Note that the compiler
                  // tries hard to make sure the frame size means RSP will be
                  // 16-byte aligned, but for leaf functions without locals (i.e.
                  // frameSize = 0) it will not be.
                  int frameSize = codeGen->genTotalFrameSize();
                  return ((8 - frameSize + off) % alignment) == 0;
              }
          }
  #endif // FEATURE_SIMD
  
          return false;
      }
  
  #ifdef DEBUG
      // Answer the question: Is a particular ISA supported?
      // Use this api when asking the question so that future
      // ISA questions can be asked correctly or when asserting
      // support/nonsupport for an instruction set
      bool compIsaSupportedDebugOnly(CORINFO_InstructionSet isa) const
      {
  #if defined(TARGET_XARCH) || defined(TARGET_ARM64)
          return (opts.compSupportsISA & (1ULL << isa)) != 0;
  #else
          return false;
  #endif
      }
  #endif // DEBUG
  
      bool notifyInstructionSetUsage(CORINFO_InstructionSet isa, bool supported) const;
  
      // Answer the question: Is a particular ISA allowed to be used implicitly by optimizations?
      // The result of this api call will exactly match the target machine
      // on which the function is executed (except for CoreLib, where there are special rules)
      bool compExactlyDependsOn(CORINFO_InstructionSet isa) const
      {
  #if defined(TARGET_XARCH) || defined(TARGET_ARM64)
          uint64_t isaBit = (1ULL << isa);
          if ((opts.compSupportsISAReported & isaBit) == 0)
          {
              if (notifyInstructionSetUsage(isa, (opts.compSupportsISA & isaBit) != 0))
                  ((Compiler*)this)->opts.compSupportsISAExactly |= isaBit;
              ((Compiler*)this)->opts.compSupportsISAReported |= isaBit;
          }
          return (opts.compSupportsISAExactly & isaBit) != 0;
  #else
          return false;
  #endif
      }
  
      // Ensure that code will not execute if an instruction set is usable. Call only
      // if the instruction set has previously reported as unusable, but when
      // that that status has not yet been recorded to the AOT compiler
      void compVerifyInstructionSetUnusable(CORINFO_InstructionSet isa)
      {
          // use compExactlyDependsOn to capture are record the use of the isa
          bool isaUsable = compExactlyDependsOn(isa);
          // Assert that the is unusable. If true, this function should never be called.
          assert(!isaUsable);
      }
  
      // Answer the question: Is a particular ISA allowed to be used implicitly by optimizations?
      // The result of this api call will match the target machine if the result is true
      // If the result is false, then the target machine may have support for the instruction
      bool compOpportunisticallyDependsOn(CORINFO_InstructionSet isa) const
      {
          if ((opts.compSupportsISA & (1ULL << isa)) != 0)
          {
              return compExactlyDependsOn(isa);
          }
          else
          {
              return false;
          }
      }
  
      // Answer the question: Is a particular ISA supported for explicit hardware intrinsics?
      bool compHWIntrinsicDependsOn(CORINFO_InstructionSet isa) const
      {
          // Report intent to use the ISA to the EE
          compExactlyDependsOn(isa);
          return ((opts.compSupportsISA & (1ULL << isa)) != 0);
      }
  
      bool canUseVexEncoding() const
      {
  #ifdef TARGET_XARCH
          return compOpportunisticallyDependsOn(InstructionSet_AVX);
  #else
          return false;
  #endif
      }
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           Compiler                                        XX
      XX                                                                           XX
      XX   Generic info about the compilation and the method being compiled.       XX
      XX   It is responsible for driving the other phases.                         XX
      XX   It is also responsible for all the memory management.                   XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      Compiler* InlineeCompiler; // The Compiler instance for the inlinee
  
      InlineResult* compInlineResult; // The result of importing the inlinee method.
  
      bool compDoAggressiveInlining;     // If true, mark every method as CORINFO_FLG_FORCEINLINE
      bool compJmpOpUsed;                // Does the method do a JMP
      bool compLongUsed;                 // Does the method use TYP_LONG
      bool compFloatingPointUsed;        // Does the method use TYP_FLOAT or TYP_DOUBLE
      bool compTailCallUsed;             // Does the method do a tailcall
      bool compTailPrefixSeen;           // Does the method IL have tail. prefix
      bool compLocallocSeen;             // Does the method IL have localloc opcode
      bool compLocallocUsed;             // Does the method use localloc.
      bool compLocallocOptimized;        // Does the method have an optimized localloc
      bool compQmarkUsed;                // Does the method use GT_QMARK/GT_COLON
      bool compQmarkRationalized;        // Is it allowed to use a GT_QMARK/GT_COLON node.
      bool compUnsafeCastUsed;           // Does the method use LDIND/STIND to cast between scalar/refernce types
      bool compHasBackwardJump;          // Does the method (or some inlinee) have a lexically backwards jump?
      bool compHasBackwardJumpInHandler; // Does the method have a lexically backwards jump in a handler?
      bool compSwitchedToOptimized;      // Codegen initially was Tier0 but jit switched to FullOpts
      bool compSwitchedToMinOpts;        // Codegen initially was Tier1/FullOpts but jit switched to MinOpts
      bool compSuppressedZeroInit;       // There are vars with lvSuppressedZeroInit set
  
  // NOTE: These values are only reliable after
  //       the importing is completely finished.
  
  #ifdef DEBUG
      // State information - which phases have completed?
      // These are kept together for easy discoverability
  
      bool    bRangeAllowStress;
      bool    compCodeGenDone;
      int64_t compNumStatementLinksTraversed; // # of links traversed while doing debug checks
      bool    fgNormalizeEHDone;              // Has the flowgraph EH normalization phase been done?
      size_t  compSizeEstimate;               // The estimated size of the method as per `gtSetEvalOrder`.
      size_t  compCycleEstimate;              // The estimated cycle count of the method as per `gtSetEvalOrder`
  #endif                                      // DEBUG
  
      bool fgLocalVarLivenessDone; // Note that this one is used outside of debug.
      bool fgLocalVarLivenessChanged;
      bool compLSRADone;
      bool compRationalIRForm;
  
      bool compUsesThrowHelper; // There is a call to a THROW_HELPER for the compiled method.
  
      bool compGeneratingProlog;
      bool compGeneratingEpilog;
      bool compNeedsGSSecurityCookie; // There is an unsafe buffer (or localloc) on the stack.
                                      // Insert cookie on frame and code to check the cookie, like VC++ -GS.
      bool compGSReorderStackLayout;  // There is an unsafe buffer on the stack, reorder locals and make local
      // copies of susceptible parameters to avoid buffer overrun attacks through locals/params
      bool getNeedsGSSecurityCookie() const
      {
          return compNeedsGSSecurityCookie;
      }
      void setNeedsGSSecurityCookie()
      {
          compNeedsGSSecurityCookie = true;
      }
  
      FrameLayoutState lvaDoneFrameLayout; // The highest frame layout state that we've completed. During
                                           // frame layout calculations, this is the level we are currently
                                           // computing.
  
      //---------------------------- JITing options -----------------------------
  
      enum codeOptimize
      {
          BLENDED_CODE,
          SMALL_CODE,
          FAST_CODE,
  
          COUNT_OPT_CODE
      };
  
      struct Options
      {
          JitFlags* jitFlags; // all flags passed from the EE
  
          // The instruction sets that the compiler is allowed to emit.
          uint64_t compSupportsISA;
          // The instruction sets that were reported to the VM as being used by the current method. Subset of
          // compSupportsISA.
          uint64_t compSupportsISAReported;
          // The instruction sets that the compiler is allowed to take advantage of implicitly during optimizations.
          // Subset of compSupportsISA.
          // The instruction sets available in compSupportsISA and not available in compSupportsISAExactly can be only
          // used via explicit hardware intrinsics.
          uint64_t compSupportsISAExactly;
  
          void setSupportedISAs(CORINFO_InstructionSetFlags isas)
          {
              compSupportsISA = isas.GetFlagsRaw();
          }
  
          unsigned compFlags; // method attributes
          unsigned instrCount;
          unsigned lvRefCount;
  
          codeOptimize compCodeOpt; // what type of code optimizations
  
          bool compUseCMOV;
  
  // optimize maximally and/or favor speed over size?
  
  #define DEFAULT_MIN_OPTS_CODE_SIZE 60000
  #define DEFAULT_MIN_OPTS_INSTR_COUNT 20000
  #define DEFAULT_MIN_OPTS_BB_COUNT 2000
  #define DEFAULT_MIN_OPTS_LV_NUM_COUNT 2000
  #define DEFAULT_MIN_OPTS_LV_REF_COUNT 8000
  
  // Maximun number of locals before turning off the inlining
  #define MAX_LV_NUM_COUNT_FOR_INLINING 512
  
          bool compMinOpts;
          bool compMinOptsIsSet;
  #ifdef DEBUG
          mutable bool compMinOptsIsUsed;
  
          bool MinOpts() const
          {
              assert(compMinOptsIsSet);
              compMinOptsIsUsed = true;
              return compMinOpts;
          }
          bool IsMinOptsSet() const
          {
              return compMinOptsIsSet;
          }
  #else  // !DEBUG
          bool MinOpts() const
          {
              return compMinOpts;
          }
          bool IsMinOptsSet() const
          {
              return compMinOptsIsSet;
          }
  #endif // !DEBUG
  
          bool OptimizationDisabled() const
          {
              return MinOpts() || compDbgCode;
          }
          bool OptimizationEnabled() const
          {
              return !OptimizationDisabled();
          }
  
          void SetMinOpts(bool val)
          {
              assert(!compMinOptsIsUsed);
              assert(!compMinOptsIsSet || (compMinOpts == val));
              compMinOpts      = val;
              compMinOptsIsSet = true;
          }
  
          // true if the CLFLG_* for an optimization is set.
          bool OptEnabled(unsigned optFlag) const
          {
              return !!(compFlags & optFlag);
          }
  
  #ifdef FEATURE_READYTORUN
          bool IsReadyToRun() const
          {
              return jitFlags->IsSet(JitFlags::JIT_FLAG_READYTORUN);
          }
  #else
          bool IsReadyToRun() const
          {
              return false;
          }
  #endif
  
          // Check if the compilation is control-flow guard enabled.
          bool IsCFGEnabled() const
          {
  #if defined(TARGET_ARM64) || defined(TARGET_AMD64)
              // On these platforms we assume the register that the target is
              // passed in is preserved by the validator and take care to get the
              // target from the register for the call (even in debug mode).
              static_assert_no_msg((RBM_VALIDATE_INDIRECT_CALL_TRASH & (1 << REG_VALIDATE_INDIRECT_CALL_ADDR)) == 0);
              if (JitConfig.JitForceControlFlowGuard())
                  return true;
  
              return jitFlags->IsSet(JitFlags::JIT_FLAG_ENABLE_CFG);
  #else
              // The remaining platforms are not supported and would require some
              // work to support.
              //
              // ARM32:
              //   The ARM32 validator does not preserve any volatile registers
              //   which means we have to take special care to allocate and use a
              //   callee-saved register (reloading the target from memory is a
              //   security issue).
              //
              // x86:
              //   On x86 some VSD calls disassemble the call site and expect an
              //   indirect call which is fundamentally incompatible with CFG.
              //   This would require a different way to pass this information
              //   through.
              //
              return false;
  #endif
          }
  
  #ifdef FEATURE_ON_STACK_REPLACEMENT
          bool IsOSR() const
          {
              return jitFlags->IsSet(JitFlags::JIT_FLAG_OSR);
          }
  #else
          bool IsOSR() const
          {
              return false;
          }
  #endif
  
          // true if we should use the PINVOKE_{BEGIN,END} helpers instead of generating
          // PInvoke transitions inline. Normally used by R2R, but also used when generating a reverse pinvoke frame, as
          // the current logic for frame setup initializes and pushes
          // the InlinedCallFrame before performing the Reverse PInvoke transition, which is invalid (as frames cannot
          // safely be pushed/popped while the thread is in a preemptive state.).
          bool ShouldUsePInvokeHelpers()
          {
              return jitFlags->IsSet(JitFlags::JIT_FLAG_USE_PINVOKE_HELPERS) ||
                     jitFlags->IsSet(JitFlags::JIT_FLAG_REVERSE_PINVOKE);
          }
  
          // true if we should use insert the REVERSE_PINVOKE_{ENTER,EXIT} helpers in the method
          // prolog/epilog
          bool IsReversePInvoke()
          {
              return jitFlags->IsSet(JitFlags::JIT_FLAG_REVERSE_PINVOKE);
          }
  
          bool compScopeInfo; // Generate the LocalVar info ?
          bool compDbgCode;   // Generate debugger-friendly code?
          bool compDbgInfo;   // Gather debugging info?
          bool compDbgEnC;
  
  #ifdef PROFILING_SUPPORTED
          bool compNoPInvokeInlineCB;
  #else
          static const bool compNoPInvokeInlineCB;
  #endif
  
  #ifdef DEBUG
          bool compGcChecks; // Check arguments and return values to ensure they are sane
  #endif
  
  #if defined(DEBUG) && defined(TARGET_XARCH)
  
          bool compStackCheckOnRet; // Check stack pointer on return to ensure it is correct.
  
  #endif // defined(DEBUG) && defined(TARGET_XARCH)
  
  #if defined(DEBUG) && defined(TARGET_X86)
  
          bool compStackCheckOnCall; // Check stack pointer after call to ensure it is correct. Only for x86.
  
  #endif // defined(DEBUG) && defined(TARGET_X86)
  
          bool compReloc; // Generate relocs for pointers in code, true for all ngen/prejit codegen
  
  #ifdef DEBUG
  #if defined(TARGET_XARCH)
          bool compEnablePCRelAddr; // Whether absolute addr be encoded as PC-rel offset by RyuJIT where possible
  #endif
  #endif // DEBUG
  
  #ifdef UNIX_AMD64_ABI
          // This flag  is indicating if there is a need to align the frame.
          // On AMD64-Windows, if there are calls, 4 slots for the outgoing ars are allocated, except for
          // FastTailCall. This slots makes the frame size non-zero, so alignment logic will be called.
          // On AMD64-Unix, there are no such slots. There is a possibility to have calls in the method with frame size of
          // 0. The frame alignment logic won't kick in. This flags takes care of the AMD64-Unix case by remembering that
          // there are calls and making sure the frame alignment logic is executed.
          bool compNeedToAlignFrame;
  #endif // UNIX_AMD64_ABI
  
          bool compProcedureSplitting; // Separate cold code from hot code
  
          bool genFPorder; // Preserve FP order (operations are non-commutative)
          bool genFPopt;   // Can we do frame-pointer-omission optimization?
          bool altJit;     // True if we are an altjit and are compiling this method
  
  #ifdef OPT_CONFIG
          bool optRepeat; // Repeat optimizer phases k times
  #endif
  
  #ifdef DEBUG
          bool compProcedureSplittingEH; // Separate cold code from hot code for functions with EH
          bool dspCode;                  // Display native code generated
          bool dspEHTable;               // Display the EH table reported to the VM
          bool dspDebugInfo;             // Display the Debug info reported to the VM
          bool dspInstrs;                // Display the IL instructions intermixed with the native code output
          bool dspLines;                 // Display source-code lines intermixed with native code output
          bool dmpHex;                   // Display raw bytes in hex of native code output
          bool varNames;                 // Display variables names in native code output
          bool disAsm;                   // Display native code as it is generated
          bool disAsmSpilled;            // Display native code when any register spilling occurs
          bool disasmWithGC;             // Display GC info interleaved with disassembly.
          bool disDiffable;              // Makes the Disassembly code 'diff-able'
          bool disAddr;                  // Display process address next to each instruction in disassembly code
          bool disAlignment;             // Display alignment boundaries in disassembly code
          bool disAsm2;                  // Display native code after it is generated using external disassembler
          bool dspOrder;                 // Display names of each of the methods that we ngen/jit
          bool dspUnwind;                // Display the unwind info output
          bool dspDiffable;     // Makes the Jit Dump 'diff-able' (currently uses same COMPlus_* flag as disDiffable)
          bool compLongAddress; // Force using large pseudo instructions for long address
                                // (IF_LARGEJMP/IF_LARGEADR/IF_LARGLDC)
          bool dspGCtbls;       // Display the GC tables
  #endif
  
          bool compExpandCallsEarly; // True if we should expand virtual call targets early for this method
  
  // Default numbers used to perform loop alignment. All the numbers are choosen
  // based on experimenting with various benchmarks.
  
  // Default minimum loop block weight required to enable loop alignment.
  #define DEFAULT_ALIGN_LOOP_MIN_BLOCK_WEIGHT 4
  
  // By default a loop will be aligned at 32B address boundary to get better
  // performance as per architecture manuals.
  #define DEFAULT_ALIGN_LOOP_BOUNDARY 0x20
  
  // For non-adaptive loop alignment, by default, only align a loop whose size is
  // at most 3 times the alignment block size. If the loop is bigger than that, it is most
  // likely complicated enough that loop alignment will not impact performance.
  #define DEFAULT_MAX_LOOPSIZE_FOR_ALIGN DEFAULT_ALIGN_LOOP_BOUNDARY * 3
  
  #ifdef DEBUG
          // Loop alignment variables
  
          // If set, for non-adaptive alignment, ensure loop jmps are not on or cross alignment boundary.
          bool compJitAlignLoopForJcc;
  #endif
          // For non-adaptive alignment, minimum loop size (in bytes) for which alignment will be done.
          unsigned short compJitAlignLoopMaxCodeSize;
  
          // Minimum weight needed for the first block of a loop to make it a candidate for alignment.
          unsigned short compJitAlignLoopMinBlockWeight;
  
          // For non-adaptive alignment, address boundary (power of 2) at which loop alignment should
          // be done. By default, 32B.
          unsigned short compJitAlignLoopBoundary;
  
          // Padding limit to align a loop.
          unsigned short compJitAlignPaddingLimit;
  
          // If set, perform adaptive loop alignment that limits number of padding based on loop size.
          bool compJitAlignLoopAdaptive;
  
          // If set, tries to hide alignment instructions behind unconditional jumps.
          bool compJitHideAlignBehindJmp;
  
  #ifdef LATE_DISASM
          bool doLateDisasm; // Run the late disassembler
  #endif                     // LATE_DISASM
  
  #if DUMP_GC_TABLES && !defined(DEBUG)
  #pragma message("NOTE: this non-debug build has GC ptr table dumping always enabled!")
          static const bool dspGCtbls = true;
  #endif
  
  #ifdef PROFILING_SUPPORTED
          // Whether to emit Enter/Leave/TailCall hooks using a dummy stub (DummyProfilerELTStub()).
          // This option helps make the JIT behave as if it is running under a profiler.
          bool compJitELTHookEnabled;
  #endif // PROFILING_SUPPORTED
  
  #if FEATURE_TAILCALL_OPT
          // Whether opportunistic or implicit tail call optimization is enabled.
          bool compTailCallOpt;
          // Whether optimization of transforming a recursive tail call into a loop is enabled.
          bool compTailCallLoopOpt;
  #endif
  
  #if FEATURE_FASTTAILCALL
          // Whether fast tail calls are allowed.
          bool compFastTailCalls;
  #endif // FEATURE_FASTTAILCALL
  
  #if defined(TARGET_ARM64)
          // Decision about whether to save FP/LR registers with callee-saved registers (see
          // COMPlus_JitSaveFpLrWithCalleSavedRegisters).
          int compJitSaveFpLrWithCalleeSavedRegisters;
  #endif // defined(TARGET_ARM64)
  
  #ifdef CONFIGURABLE_ARM_ABI
          bool compUseSoftFP = false;
  #else
  #ifdef ARM_SOFTFP
          static const bool compUseSoftFP = true;
  #else  // !ARM_SOFTFP
          static const bool compUseSoftFP = false;
  #endif // ARM_SOFTFP
  #endif // CONFIGURABLE_ARM_ABI
      } opts;
  
      static bool                s_pAltJitExcludeAssembliesListInitialized;
      static AssemblyNamesList2* s_pAltJitExcludeAssembliesList;
  
  #ifdef DEBUG
      static bool                s_pJitDisasmIncludeAssembliesListInitialized;
      static AssemblyNamesList2* s_pJitDisasmIncludeAssembliesList;
  
      static bool       s_pJitFunctionFileInitialized;
      static MethodSet* s_pJitMethodSet;
  #endif // DEBUG
  
  #ifdef DEBUG
  // silence warning of cast to greater size. It is easier to silence than construct code the compiler is happy with, and
  // it is safe in this case
  #pragma warning(push)
  #pragma warning(disable : 4312)
  
      template <typename T>
      T dspPtr(T p)
      {
          return (p == ZERO) ? ZERO : (opts.dspDiffable ? T(0xD1FFAB1E) : p);
      }
  
      template <typename T>
      T dspOffset(T o)
      {
          return (o == ZERO) ? ZERO : (opts.dspDiffable ? T(0xD1FFAB1E) : o);
      }
  #pragma warning(pop)
  
      static int dspTreeID(GenTree* tree)
      {
          return tree->gtTreeID;
      }
  
      static void printStmtID(Statement* stmt)
      {
          assert(stmt != nullptr);
          printf(FMT_STMT, stmt->GetID());
      }
  
      static void printTreeID(GenTree* tree)
      {
          if (tree == nullptr)
          {
              printf("[------]");
          }
          else
          {
              printf("[%06d]", dspTreeID(tree));
          }
      }
  
      const char* pgoSourceToString(ICorJitInfo::PgoSource p);
      const char* devirtualizationDetailToString(CORINFO_DEVIRTUALIZATION_DETAIL detail);
  
  #endif // DEBUG
  
  // clang-format off
  #define STRESS_MODES                                                                            \
                                                                                                  \
          STRESS_MODE(NONE)                                                                       \
                                                                                                  \
          /* "Variations" stress areas which we try to mix up with each other. */                 \
          /* These should not be exhaustively used as they might */                               \
          /* hide/trivialize other areas */                                                       \
                                                                                                  \
          STRESS_MODE(REGS)                                                                       \
          STRESS_MODE(DBL_ALN)                                                                    \
          STRESS_MODE(LCL_FLDS)                                                                   \
          STRESS_MODE(UNROLL_LOOPS)                                                               \
          STRESS_MODE(MAKE_CSE)                                                                   \
          STRESS_MODE(LEGACY_INLINE)                                                              \
          STRESS_MODE(CLONE_EXPR)                                                                 \
          STRESS_MODE(USE_CMOV)                                                                   \
          STRESS_MODE(FOLD)                                                                       \
          STRESS_MODE(MERGED_RETURNS)                                                             \
          STRESS_MODE(BB_PROFILE)                                                                 \
          STRESS_MODE(OPT_BOOLS_GC)                                                               \
          STRESS_MODE(REMORPH_TREES)                                                              \
          STRESS_MODE(64RSLT_MUL)                                                                 \
          STRESS_MODE(DO_WHILE_LOOPS)                                                             \
          STRESS_MODE(MIN_OPTS)                                                                   \
          STRESS_MODE(REVERSE_FLAG)     /* Will set GTF_REVERSE_OPS whenever we can */            \
          STRESS_MODE(REVERSE_COMMA)    /* Will reverse commas created  with gtNewCommaNode */    \
          STRESS_MODE(TAILCALL)         /* Will make the call as a tailcall whenever legal */     \
          STRESS_MODE(CATCH_ARG)        /* Will spill catch arg */                                \
          STRESS_MODE(UNSAFE_BUFFER_CHECKS)                                                       \
          STRESS_MODE(NULL_OBJECT_CHECK)                                                          \
          STRESS_MODE(PINVOKE_RESTORE_ESP)                                                        \
          STRESS_MODE(RANDOM_INLINE)                                                              \
          STRESS_MODE(SWITCH_CMP_BR_EXPANSION)                                                    \
          STRESS_MODE(GENERIC_VARN)                                                               \
          STRESS_MODE(PROFILER_CALLBACKS) /* Will generate profiler hooks for ELT callbacks */    \
          STRESS_MODE(BYREF_PROMOTION) /* Change undoPromotion decisions for byrefs */            \
          STRESS_MODE(PROMOTE_FEWER_STRUCTS)/* Don't promote some structs that can be promoted */ \
          STRESS_MODE(VN_BUDGET)/* Randomize the VN budget */                                     \
                                                                                                  \
          /* After COUNT_VARN, stress level 2 does all of these all the time */                   \
                                                                                                  \
          STRESS_MODE(COUNT_VARN)                                                                 \
                                                                                                  \
          /* "Check" stress areas that can be exhaustively used if we */                          \
          /*  dont care about performance at all */                                               \
                                                                                                  \
          STRESS_MODE(FORCE_INLINE) /* Treat every method as AggressiveInlining */                \
          STRESS_MODE(CHK_FLOW_UPDATE)                                                            \
          STRESS_MODE(EMITTER)                                                                    \
          STRESS_MODE(CHK_REIMPORT)                                                               \
          STRESS_MODE(FLATFP)                                                                     \
          STRESS_MODE(GENERIC_CHECK)                                                              \
          STRESS_MODE(COUNT)
  
      enum                compStressArea
      {
  #define STRESS_MODE(mode) STRESS_##mode,
          STRESS_MODES
  #undef STRESS_MODE
      };
  // clang-format on
  
  #ifdef DEBUG
      static const LPCWSTR s_compStressModeNames[STRESS_COUNT + 1];
      BYTE                 compActiveStressModes[STRESS_COUNT];
  #endif // DEBUG
  
  #define MAX_STRESS_WEIGHT 100
  
      bool compStressCompile(compStressArea stressArea, unsigned weightPercentage);
      bool compStressCompileHelper(compStressArea stressArea, unsigned weightPercentage);
  
  #ifdef DEBUG
  
      bool compInlineStress()
      {
          return compStressCompile(STRESS_LEGACY_INLINE, 50);
      }
  
      bool compRandomInlineStress()
      {
          return compStressCompile(STRESS_RANDOM_INLINE, 50);
      }
  
      bool compPromoteFewerStructs(unsigned lclNum);
  
  #endif // DEBUG
  
      bool compTailCallStress()
      {
  #ifdef DEBUG
          // Do not stress tailcalls in IL stubs as the runtime creates several IL
          // stubs to implement the tailcall mechanism, which would then
          // recursively create more IL stubs.
          return !opts.jitFlags->IsSet(JitFlags::JIT_FLAG_IL_STUB) &&
                 (JitConfig.TailcallStress() != 0 || compStressCompile(STRESS_TAILCALL, 5));
  #else
          return false;
  #endif
      }
  
      const char* compGetTieringName(bool wantShortName = false) const;
      const char* compGetStressMessage() const;
  
      codeOptimize compCodeOpt() const
      {
  #if 0
          // Switching between size & speed has measurable throughput impact
          // (3.5% on NGen CoreLib when measured). It used to be enabled for
          // DEBUG, but should generate identical code between CHK & RET builds,
          // so that's not acceptable.
          // TODO-Throughput: Figure out what to do about size vs. speed & throughput.
          //                  Investigate the cause of the throughput regression.
  
          return opts.compCodeOpt;
  #else
          return BLENDED_CODE;
  #endif
      }
  
      //--------------------- Info about the procedure --------------------------
  
      struct Info
      {
          COMP_HANDLE           compCompHnd;
          CORINFO_MODULE_HANDLE compScopeHnd;
          CORINFO_CLASS_HANDLE  compClassHnd;
          CORINFO_METHOD_HANDLE compMethodHnd;
          CORINFO_METHOD_INFO*  compMethodInfo;
  
          bool hasCircularClassConstraints;
          bool hasCircularMethodConstraints;
  
  #if defined(DEBUG) || defined(LATE_DISASM) || DUMP_FLOWGRAPHS
  
          const char* compMethodName;
          const char* compClassName;
          const char* compFullName;
          double      compPerfScore;
          int         compMethodSuperPMIIndex; // useful when debugging under SuperPMI
  
  #endif // defined(DEBUG) || defined(LATE_DISASM) || DUMP_FLOWGRAPHS
  
  #if defined(DEBUG) || defined(INLINE_DATA)
          // Method hash is logically const, but computed
          // on first demand.
          mutable unsigned compMethodHashPrivate;
          unsigned         compMethodHash() const;
  #endif // defined(DEBUG) || defined(INLINE_DATA)
  
  #ifdef PSEUDORANDOM_NOP_INSERTION
          // things for pseudorandom nop insertion
          unsigned  compChecksum;
          CLRRandom compRNG;
  #endif
  
          // The following holds the FLG_xxxx flags for the method we're compiling.
          unsigned compFlags;
  
          // The following holds the class attributes for the method we're compiling.
          unsigned compClassAttr;
  
          const BYTE*     compCode;
          IL_OFFSET       compILCodeSize;     // The IL code size
          IL_OFFSET       compILImportSize;   // Estimated amount of IL actually imported
          IL_OFFSET       compILEntry;        // The IL entry point (normally 0)
          PatchpointInfo* compPatchpointInfo; // Patchpoint data for OSR (normally nullptr)
          UNATIVE_OFFSET  compNativeCodeSize; // The native code size, after instructions are issued. This
          // is less than (compTotalHotCodeSize + compTotalColdCodeSize) only if:
          // (1) the code is not hot/cold split, and we issued less code than we expected, or
          // (2) the code is hot/cold split, and we issued less code than we expected
          // in the cold section (the hot section will always be padded out to compTotalHotCodeSize).
  
          bool compIsStatic : 1;           // Is the method static (no 'this' pointer)?
          bool compIsVarArgs : 1;          // Does the method have varargs parameters?
          bool compInitMem : 1;            // Is the CORINFO_OPT_INIT_LOCALS bit set in the method info options?
          bool compProfilerCallback : 1;   // JIT inserted a profiler Enter callback
          bool compPublishStubParam : 1;   // EAX captured in prolog will be available through an intrinsic
          bool compHasNextCallRetAddr : 1; // The NextCallReturnAddress intrinsic is used.
  
          var_types compRetType;       // Return type of the method as declared in IL
          var_types compRetNativeType; // Normalized return type as per target arch ABI
          unsigned  compILargsCount;   // Number of arguments (incl. implicit but not hidden)
          unsigned  compArgsCount;     // Number of arguments (incl. implicit and     hidden)
  
  #if FEATURE_FASTTAILCALL
          unsigned compArgStackSize; // Incoming argument stack size in bytes
  #endif                             // FEATURE_FASTTAILCALL
  
          unsigned compRetBuffArg; // position of hidden return param var (0, 1) (BAD_VAR_NUM means not present);
          int compTypeCtxtArg; // position of hidden param for type context for generic code (CORINFO_CALLCONV_PARAMTYPE)
          unsigned       compThisArg; // position of implicit this pointer param (not to be confused with lvaArg0Var)
          unsigned       compILlocalsCount; // Number of vars : args + locals (incl. implicit but not hidden)
          unsigned       compLocalsCount;   // Number of vars : args + locals (incl. implicit and     hidden)
          unsigned       compMaxStack;
          UNATIVE_OFFSET compTotalHotCodeSize;  // Total number of bytes of Hot Code in the method
          UNATIVE_OFFSET compTotalColdCodeSize; // Total number of bytes of Cold Code in the method
  
          unsigned compUnmanagedCallCountWithGCTransition; // count of unmanaged calls with GC transition.
  
          CorInfoCallConvExtension compCallConv; // The entry-point calling convention for this method.
  
          unsigned compLvFrameListRoot; // lclNum for the Frame root
          unsigned compXcptnsCount;     // Number of exception-handling clauses read in the method's IL.
                                        // You should generally use compHndBBtabCount instead: it is the
                                        // current number of EH clauses (after additions like synchronized
          // methods and funclets, and removals like unreachable code deletion).
  
          Target::ArgOrder compArgOrder;
  
          bool compMatchedVM; // true if the VM is "matched": either the JIT is a cross-compiler
                              // and the VM expects that, or the JIT is a "self-host" compiler
                              // (e.g., x86 hosted targeting x86) and the VM expects that.
  
          /*  The following holds IL scope information about local variables.
           */
  
          unsigned     compVarScopesCount;
          VarScopeDsc* compVarScopes;
  
          /* The following holds information about instr offsets for
           * which we need to report IP-mappings
           */
  
          IL_OFFSET*                   compStmtOffsets; // sorted
          unsigned                     compStmtOffsetsCount;
          ICorDebugInfo::BoundaryTypes compStmtOffsetsImplicit;
  
  #define CPU_X86 0x0100 // The generic X86 CPU
  #define CPU_X86_PENTIUM_4 0x0110
  
  #define CPU_X64 0x0200       // The generic x64 CPU
  #define CPU_AMD_X64 0x0210   // AMD x64 CPU
  #define CPU_INTEL_X64 0x0240 // Intel x64 CPU
  
  #define CPU_ARM 0x0300   // The generic ARM CPU
  #define CPU_ARM64 0x0400 // The generic ARM64 CPU
  
          unsigned genCPU; // What CPU are we running on
  
          // Number of class profile probes in this method
          unsigned compClassProbeCount;
  
      } info;
  
      // Returns true if the method being compiled returns a non-void and non-struct value.
      // Note that lvaInitTypeRef() normalizes compRetNativeType for struct returns in a
      // single register as per target arch ABI (e.g on Amd64 Windows structs of size 1, 2,
      // 4 or 8 gets normalized to TYP_BYTE/TYP_SHORT/TYP_INT/TYP_LONG; On Arm HFA structs).
      // Methods returning such structs are considered to return non-struct return value and
      // this method returns true in that case.
      bool compMethodReturnsNativeScalarType()
      {
          return (info.compRetType != TYP_VOID) && !varTypeIsStruct(info.compRetNativeType);
      }
  
      // Returns true if the method being compiled returns RetBuf addr as its return value
      bool compMethodReturnsRetBufAddr()
      {
          // There are cases where implicit RetBuf argument should be explicitly returned in a register.
          // In such cases the return type is changed to TYP_BYREF and appropriate IR is generated.
          // These cases are:
          CLANG_FORMAT_COMMENT_ANCHOR;
  #ifdef TARGET_AMD64
          // 1. on x64 Windows and Unix the address of RetBuf needs to be returned by
          //    methods with hidden RetBufArg in RAX. In such case GT_RETURN is of TYP_BYREF,
          //    returning the address of RetBuf.
          return (info.compRetBuffArg != BAD_VAR_NUM);
  #else // TARGET_AMD64
  #ifdef PROFILING_SUPPORTED
          // 2.  Profiler Leave callback expects the address of retbuf as return value for
          //    methods with hidden RetBuf argument.  impReturnInstruction() when profiler
          //    callbacks are needed creates GT_RETURN(TYP_BYREF, op1 = Addr of RetBuf) for
          //    methods with hidden RetBufArg.
          if (compIsProfilerHookNeeded())
          {
              return (info.compRetBuffArg != BAD_VAR_NUM);
          }
  #endif
          // 3. Windows ARM64 native instance calling convention requires the address of RetBuff
          //    to be returned in x0.
          CLANG_FORMAT_COMMENT_ANCHOR;
  #if defined(TARGET_ARM64)
          if (TargetOS::IsWindows)
          {
              auto callConv = info.compCallConv;
              if (callConvIsInstanceMethodCallConv(callConv))
              {
                  return (info.compRetBuffArg != BAD_VAR_NUM);
              }
          }
  #endif // TARGET_ARM64
          // 4. x86 unmanaged calling conventions require the address of RetBuff to be returned in eax.
          CLANG_FORMAT_COMMENT_ANCHOR;
  #if defined(TARGET_X86)
          if (info.compCallConv != CorInfoCallConvExtension::Managed)
          {
              return (info.compRetBuffArg != BAD_VAR_NUM);
          }
  #endif
  
          return false;
  #endif // TARGET_AMD64
      }
  
      // Returns true if the method returns a value in more than one return register
      // TODO-ARM-Bug: Deal with multi-register genReturnLocaled structs?
      // TODO-ARM64: Does this apply for ARM64 too?
      bool compMethodReturnsMultiRegRetType()
      {
  #if FEATURE_MULTIREG_RET
  #if defined(TARGET_X86)
          // On x86, 64-bit longs and structs are returned in multiple registers
          return varTypeIsLong(info.compRetNativeType) ||
                 (varTypeIsStruct(info.compRetNativeType) && (info.compRetBuffArg == BAD_VAR_NUM));
  #else  // targets: X64-UNIX, ARM64 or ARM32
          // On all other targets that support multireg return values:
          // Methods returning a struct in multiple registers have a return value of TYP_STRUCT.
          // Such method's compRetNativeType is TYP_STRUCT without a hidden RetBufArg
          return varTypeIsStruct(info.compRetNativeType) && (info.compRetBuffArg == BAD_VAR_NUM);
  #endif // TARGET_XXX
  
  #else // not FEATURE_MULTIREG_RET
  
          // For this architecture there are no multireg returns
          return false;
  
  #endif // FEATURE_MULTIREG_RET
      }
  
      bool compEnregLocals()
      {
          return ((opts.compFlags & CLFLG_REGVAR) != 0);
      }
  
      bool compEnregStructLocals()
      {
          return (JitConfig.JitEnregStructLocals() != 0);
      }
  
      bool compObjectStackAllocation()
      {
          return (JitConfig.JitObjectStackAllocation() != 0);
      }
  
      // Returns true if the method returns a value in more than one return register,
      // it should replace/be  merged with compMethodReturnsMultiRegRetType when #36868 is fixed.
      // The difference from original `compMethodReturnsMultiRegRetType` is in ARM64 SIMD* handling,
      // this method correctly returns false for it (it is passed as HVA), when the original returns true.
      bool compMethodReturnsMultiRegRegTypeAlternate()
      {
  #if FEATURE_MULTIREG_RET
  #if defined(TARGET_X86)
          // On x86, 64-bit longs and structs are returned in multiple registers
          return varTypeIsLong(info.compRetNativeType) ||
                 (varTypeIsStruct(info.compRetNativeType) && (info.compRetBuffArg == BAD_VAR_NUM));
  #else // targets: X64-UNIX, ARM64 or ARM32
  #if defined(TARGET_ARM64)
          // TYP_SIMD* are returned in one register.
          if (varTypeIsSIMD(info.compRetNativeType))
          {
              return false;
          }
  #endif
          // On all other targets that support multireg return values:
          // Methods returning a struct in multiple registers have a return value of TYP_STRUCT.
          // Such method's compRetNativeType is TYP_STRUCT without a hidden RetBufArg
          return varTypeIsStruct(info.compRetNativeType) && (info.compRetBuffArg == BAD_VAR_NUM);
  #endif // TARGET_XXX
  
  #else // not FEATURE_MULTIREG_RET
  
          // For this architecture there are no multireg returns
          return false;
  
  #endif // FEATURE_MULTIREG_RET
      }
  
      // Returns true if the method being compiled returns a value
      bool compMethodHasRetVal()
      {
          return compMethodReturnsNativeScalarType() || compMethodReturnsRetBufAddr() ||
                 compMethodReturnsMultiRegRetType();
      }
  
      // Returns true if the method requires a PInvoke prolog and epilog
      bool compMethodRequiresPInvokeFrame()
      {
          return (info.compUnmanagedCallCountWithGCTransition > 0);
      }
  
      // Returns true if address-exposed user variables should be poisoned with a recognizable value
      bool compShouldPoisonFrame()
      {
  #ifdef FEATURE_ON_STACK_REPLACEMENT
          if (opts.IsOSR())
              return false;
  #endif
          return !info.compInitMem && opts.compDbgCode;
      }
  
      // Returns true if the jit supports having patchpoints in this method.
      // Optionally, get the reason why not.
      bool compCanHavePatchpoints(const char** reason = nullptr);
  
  #if defined(DEBUG)
  
      void compDispLocalVars();
  
  #endif // DEBUG
  
  private:
      class ClassLayoutTable* m_classLayoutTable;
  
      class ClassLayoutTable* typCreateClassLayoutTable();
      class ClassLayoutTable* typGetClassLayoutTable();
  
  public:
      // Get the layout having the specified layout number.
      ClassLayout* typGetLayoutByNum(unsigned layoutNum);
      // Get the layout number of the specified layout.
      unsigned typGetLayoutNum(ClassLayout* layout);
      // Get the layout having the specified size but no class handle.
      ClassLayout* typGetBlkLayout(unsigned blockSize);
      // Get the number of a layout having the specified size but no class handle.
      unsigned typGetBlkLayoutNum(unsigned blockSize);
      // Get the layout for the specified class handle.
      ClassLayout* typGetObjLayout(CORINFO_CLASS_HANDLE classHandle);
      // Get the number of a layout for the specified class handle.
      unsigned typGetObjLayoutNum(CORINFO_CLASS_HANDLE classHandle);
  
  //-------------------------- Global Compiler Data ------------------------------------
  
  #ifdef DEBUG
  private:
      static LONG s_compMethodsCount; // to produce unique label names
  #endif
  
  public:
  #ifdef DEBUG
      LONG     compMethodID;
      unsigned compGenTreeID;
      unsigned compStatementID;
      unsigned compBasicBlockID;
  #endif
  
      BasicBlock* compCurBB;   // the current basic block in process
      Statement*  compCurStmt; // the current statement in process
      GenTree*    compCurTree; // the current tree in process
  
      //  The following is used to create the 'method JIT info' block.
      size_t compInfoBlkSize;
      BYTE*  compInfoBlkAddr;
  
      EHblkDsc* compHndBBtab;           // array of EH data
      unsigned  compHndBBtabCount;      // element count of used elements in EH data array
      unsigned  compHndBBtabAllocCount; // element count of allocated elements in EH data array
  
  #if defined(TARGET_X86)
  
      //-------------------------------------------------------------------------
      //  Tracking of region covered by the monitor in synchronized methods
      void* syncStartEmitCookie; // the emitter cookie for first instruction after the call to MON_ENTER
      void* syncEndEmitCookie;   // the emitter cookie for first instruction after the call to MON_EXIT
  
  #endif // !TARGET_X86
  
      Phases      mostRecentlyActivePhase; // the most recently active phase
      PhaseChecks activePhaseChecks;       // the currently active phase checks
  
      //-------------------------------------------------------------------------
      //  The following keeps track of how many bytes of local frame space we've
      //  grabbed so far in the current function, and how many argument bytes we
      //  need to pop when we return.
      //
  
      unsigned compLclFrameSize; // secObject+lclBlk+locals+temps
  
      // Count of callee-saved regs we pushed in the prolog.
      // Does not include EBP for isFramePointerUsed() and double-aligned frames.
      // In case of Amd64 this doesn't include float regs saved on stack.
      unsigned compCalleeRegsPushed;
  
  #if defined(TARGET_XARCH)
      // Mask of callee saved float regs on stack.
      regMaskTP compCalleeFPRegsSavedMask;
  #endif
  #ifdef TARGET_AMD64
  // Quirk for VS debug-launch scenario to work:
  // Bytes of padding between save-reg area and locals.
  #define VSQUIRK_STACK_PAD (2 * REGSIZE_BYTES)
      unsigned compVSQuirkStackPaddingNeeded;
  #endif
  
      unsigned compArgSize; // total size of arguments in bytes (including register args (lvIsRegArg))
  
      unsigned compMapILargNum(unsigned ILargNum);      // map accounting for hidden args
      unsigned compMapILvarNum(unsigned ILvarNum);      // map accounting for hidden args
      unsigned compMap2ILvarNum(unsigned varNum) const; // map accounting for hidden args
  
  #if defined(TARGET_ARM64)
      struct FrameInfo
      {
          // Frame type (1-5)
          int frameType;
  
          // Distance from established (method body) SP to base of callee save area
          int calleeSaveSpOffset;
  
          // Amount to subtract from SP before saving (prolog) OR
          // to add to SP after restoring (epilog) callee saves
          int calleeSaveSpDelta;
  
          // Distance from established SP to where caller's FP was saved
          int offsetSpToSavedFp;
      } compFrameInfo;
  #endif
  
      //-------------------------------------------------------------------------
  
      static void compStartup();  // One-time initialization
      static void compShutdown(); // One-time finalization
  
      void compInit(ArenaAllocator*       pAlloc,
                    CORINFO_METHOD_HANDLE methodHnd,
                    COMP_HANDLE           compHnd,
                    CORINFO_METHOD_INFO*  methodInfo,
                    InlineInfo*           inlineInfo);
      void compDone();
  
      static void compDisplayStaticSizes(FILE* fout);
  
      //------------ Some utility functions --------------
  
      void* compGetHelperFtn(CorInfoHelpFunc ftnNum,         /* IN  */
                             void**          ppIndirection); /* OUT */
  
      // Several JIT/EE interface functions return a CorInfoType, and also return a
      // class handle as an out parameter if the type is a value class.  Returns the
      // size of the type these describe.
      unsigned compGetTypeSize(CorInfoType cit, CORINFO_CLASS_HANDLE clsHnd);
  
      // Returns true if the method being compiled has a return buffer.
      bool compHasRetBuffArg();
  
  #ifdef DEBUG
      // Components used by the compiler may write unit test suites, and
      // have them run within this method.  They will be run only once per process, and only
      // in debug.  (Perhaps should be under the control of a COMPlus_ flag.)
      // These should fail by asserting.
      void compDoComponentUnitTestsOnce();
  #endif // DEBUG
  
      int compCompile(CORINFO_MODULE_HANDLE classPtr,
                      void**                methodCodePtr,
                      uint32_t*             methodCodeSize,
                      JitFlags*             compileFlags);
      void compCompileFinish();
      int compCompileHelper(CORINFO_MODULE_HANDLE classPtr,
                            COMP_HANDLE           compHnd,
                            CORINFO_METHOD_INFO*  methodInfo,
                            void**                methodCodePtr,
                            uint32_t*             methodCodeSize,
                            JitFlags*             compileFlag);
  
      ArenaAllocator* compGetArenaAllocator();
  
      void generatePatchpointInfo();
  
  #if MEASURE_MEM_ALLOC
      static bool s_dspMemStats; // Display per-phase memory statistics for every function
  #endif                         // MEASURE_MEM_ALLOC
  
  #if LOOP_HOIST_STATS
      unsigned m_loopsConsidered;
      bool     m_curLoopHasHoistedExpression;
      unsigned m_loopsWithHoistedExpressions;
      unsigned m_totalHoistedExpressions;
  
      void AddLoopHoistStats();
      void PrintPerMethodLoopHoistStats();
  
      static CritSecObject s_loopHoistStatsLock; // This lock protects the data structures below.
      static unsigned      s_loopsConsidered;
      static unsigned      s_loopsWithHoistedExpressions;
      static unsigned      s_totalHoistedExpressions;
  
      static void PrintAggregateLoopHoistStats(FILE* f);
  #endif // LOOP_HOIST_STATS
  
  #if TRACK_ENREG_STATS
      class EnregisterStats
      {
      private:
          unsigned m_totalNumberOfVars;
          unsigned m_totalNumberOfStructVars;
          unsigned m_totalNumberOfEnregVars;
          unsigned m_totalNumberOfStructEnregVars;
  
          unsigned m_addrExposed;
          unsigned m_VMNeedsStackAddr;
          unsigned m_localField;
          unsigned m_blockOp;
          unsigned m_dontEnregStructs;
          unsigned m_notRegSizeStruct;
          unsigned m_structArg;
          unsigned m_lclAddrNode;
          unsigned m_castTakesAddr;
          unsigned m_storeBlkSrc;
          unsigned m_oneAsgRetyping;
          unsigned m_swizzleArg;
          unsigned m_blockOpRet;
          unsigned m_returnSpCheck;
          unsigned m_simdUserForcesDep;
          unsigned m_liveInOutHndlr;
          unsigned m_depField;
          unsigned m_noRegVars;
          unsigned m_minOptsGC;
  #ifdef JIT32_GCENCODER
          unsigned m_PinningRef;
  #endif // JIT32_GCENCODER
  #if !defined(TARGET_64BIT)
          unsigned m_longParamField;
  #endif // !TARGET_64BIT
          unsigned m_parentExposed;
          unsigned m_tooConservative;
          unsigned m_escapeAddress;
          unsigned m_osrExposed;
          unsigned m_stressLclFld;
          unsigned m_copyFldByFld;
          unsigned m_dispatchRetBuf;
          unsigned m_wideIndir;
  
      public:
          void RecordLocal(const LclVarDsc* varDsc);
          void Dump(FILE* fout) const;
      };
  
      static EnregisterStats s_enregisterStats;
  #endif // TRACK_ENREG_STATS
  
      bool compIsForImportOnly();
      bool compIsForInlining() const;
      bool compDonotInline();
  
  #ifdef DEBUG
      // Get the default fill char value we randomize this value when JitStress is enabled.
      static unsigned char compGetJitDefaultFill(Compiler* comp);
  
      const char* compLocalVarName(unsigned varNum, unsigned offs);
      VarName compVarName(regNumber reg, bool isFloatReg = false);
      const char* compRegVarName(regNumber reg, bool displayVar = false, bool isFloatReg = false);
      const char* compRegNameForSize(regNumber reg, size_t size);
      const char* compFPregVarName(unsigned fpReg, bool displayVar = false);
      void compDspSrcLinesByNativeIP(UNATIVE_OFFSET curIP);
      void compDspSrcLinesByLineNum(unsigned line, bool seek = false);
  #endif // DEBUG
  
      //-------------------------------------------------------------------------
  
      struct VarScopeListNode
      {
          VarScopeDsc*             data;
          VarScopeListNode*        next;
          static VarScopeListNode* Create(VarScopeDsc* value, CompAllocator alloc)
          {
              VarScopeListNode* node = new (alloc) VarScopeListNode;
              node->data             = value;
              node->next             = nullptr;
              return node;
          }
      };
  
      struct VarScopeMapInfo
      {
          VarScopeListNode*       head;
          VarScopeListNode*       tail;
          static VarScopeMapInfo* Create(VarScopeListNode* node, CompAllocator alloc)
          {
              VarScopeMapInfo* info = new (alloc) VarScopeMapInfo;
              info->head            = node;
              info->tail            = node;
              return info;
          }
      };
  
      // Max value of scope count for which we would use linear search; for larger values we would use hashtable lookup.
      static const unsigned MAX_LINEAR_FIND_LCL_SCOPELIST = 32;
  
      typedef JitHashTable<unsigned, JitSmallPrimitiveKeyFuncs<unsigned>, VarScopeMapInfo*> VarNumToScopeDscMap;
  
      // Map to keep variables' scope indexed by varNum containing it's scope dscs at the index.
      VarNumToScopeDscMap* compVarScopeMap;
  
      VarScopeDsc* compFindLocalVar(unsigned varNum, unsigned lifeBeg, unsigned lifeEnd);
  
      VarScopeDsc* compFindLocalVar(unsigned varNum, unsigned offs);
  
      VarScopeDsc* compFindLocalVarLinear(unsigned varNum, unsigned offs);
  
      void compInitVarScopeMap();
  
      VarScopeDsc** compEnterScopeList; // List has the offsets where variables
                                        // enter scope, sorted by instr offset
      unsigned compNextEnterScope;
  
      VarScopeDsc** compExitScopeList; // List has the offsets where variables
                                       // go out of scope, sorted by instr offset
      unsigned compNextExitScope;
  
      void compInitScopeLists();
  
      void compResetScopeLists();
  
      VarScopeDsc* compGetNextEnterScope(unsigned offs, bool scan = false);
  
      VarScopeDsc* compGetNextExitScope(unsigned offs, bool scan = false);
  
      void compProcessScopesUntil(unsigned   offset,
                                  VARSET_TP* inScope,
                                  void (Compiler::*enterScopeFn)(VARSET_TP* inScope, VarScopeDsc*),
                                  void (Compiler::*exitScopeFn)(VARSET_TP* inScope, VarScopeDsc*));
  
  #ifdef DEBUG
      void compDispScopeLists();
  #endif // DEBUG
  
      bool compIsProfilerHookNeeded();
  
      //-------------------------------------------------------------------------
      /*               Statistical Data Gathering                               */
  
      void compJitStats(); // call this function and enable
                           // various ifdef's below for statistical data
  
  #if CALL_ARG_STATS
      void        compCallArgStats();
      static void compDispCallArgStats(FILE* fout);
  #endif
  
      //-------------------------------------------------------------------------
  
  protected:
  #ifdef DEBUG
      bool skipMethod();
  #endif
  
      ArenaAllocator* compArenaAllocator;
  
  public:
      void compFunctionTraceStart();
      void compFunctionTraceEnd(void* methodCodePtr, ULONG methodCodeSize, bool isNYI);
  
  protected:
      size_t compMaxUncheckedOffsetForNullObject;
  
      void compInitOptions(JitFlags* compileFlags);
  
      void compSetProcessor();
      void compInitDebuggingInfo();
      void compSetOptimizationLevel();
  #ifdef TARGET_ARMARCH
      bool compRsvdRegCheck(FrameLayoutState curState);
  #endif
      void compCompile(void** methodCodePtr, uint32_t* methodCodeSize, JitFlags* compileFlags);
  
      // Clear annotations produced during optimizations; to be used between iterations when repeating opts.
      void ResetOptAnnotations();
  
      // Regenerate loop descriptors; to be used between iterations when repeating opts.
      void RecomputeLoopInfo();
  
  #ifdef PROFILING_SUPPORTED
      // Data required for generating profiler Enter/Leave/TailCall hooks
  
      bool  compProfilerHookNeeded; // Whether profiler Enter/Leave/TailCall hook needs to be generated for the method
      void* compProfilerMethHnd;    // Profiler handle of the method being compiled. Passed as param to ELT callbacks
      bool  compProfilerMethHndIndirected; // Whether compProfilerHandle is pointer to the handle or is an actual handle
  #endif
  
  public:
      // Assumes called as part of process shutdown; does any compiler-specific work associated with that.
      static void ProcessShutdownWork(ICorStaticInfo* statInfo);
  
      CompAllocator getAllocator(CompMemKind cmk = CMK_Generic)
      {
          return CompAllocator(compArenaAllocator, cmk);
      }
  
      CompAllocator getAllocatorGC()
      {
          return getAllocator(CMK_GC);
      }
  
      CompAllocator getAllocatorLoopHoist()
      {
          return getAllocator(CMK_LoopHoist);
      }
  
  #ifdef DEBUG
      CompAllocator getAllocatorDebugOnly()
      {
          return getAllocator(CMK_DebugOnly);
      }
  #endif // DEBUG
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           typeInfo                                        XX
      XX                                                                           XX
      XX   Checks for type compatibility and merges types                          XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      // Returns true if child is equal to or a subtype of parent for merge purposes
      // This support is necessary to suport attributes that are not described in
      // for example, signatures. For example, the permanent home byref (byref that
      // points to the gc heap), isn't a property of method signatures, therefore,
      // it is safe to have mismatches here (that tiCompatibleWith will not flag),
      // but when deciding if we need to reimport a block, we need to take these
      // in account
      bool tiMergeCompatibleWith(const typeInfo& pChild, const typeInfo& pParent, bool normalisedForStack) const;
  
      // Returns true if child is equal to or a subtype of parent.
      // normalisedForStack indicates that both types are normalised for the stack
      bool tiCompatibleWith(const typeInfo& pChild, const typeInfo& pParent, bool normalisedForStack) const;
  
      // Merges pDest and pSrc. Returns false if merge is undefined.
      // *pDest is modified to represent the merged type.  Sets "*changed" to true
      // if this changes "*pDest".
      bool tiMergeToCommonParent(typeInfo* pDest, const typeInfo* pSrc, bool* changed) const;
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                           IL verification stuff                           XX
      XX                                                                           XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  
  public:
      // The following is used to track liveness of local variables, initialization
      // of valueclass constructors, and type safe use of IL instructions.
  
      // dynamic state info needed for verification
      EntryState verCurrentState;
  
      // this ptr of object type .ctors are considered intited only after
      // the base class ctor is called, or an alternate ctor is called.
      // An uninited this ptr can be used to access fields, but cannot
      // be used to call a member function.
      bool verTrackObjCtorInitState;
  
      void verInitBBEntryState(BasicBlock* block, EntryState* currentState);
  
      // Requires that "tis" is not TIS_Bottom -- it's a definite init/uninit state.
      void verSetThisInit(BasicBlock* block, ThisInitState tis);
      void verInitCurrentState();
      void verResetCurrentState(BasicBlock* block, EntryState* currentState);
  
      // Merges the current verification state into the entry state of "block", return false if that merge fails,
      // TRUE if it succeeds.  Further sets "*changed" to true if this changes the entry state of "block".
      bool verMergeEntryStates(BasicBlock* block, bool* changed);
  
      void verConvertBBToThrowVerificationException(BasicBlock* block DEBUGARG(bool logMsg));
      void verHandleVerificationFailure(BasicBlock* block DEBUGARG(bool logMsg));
      typeInfo verMakeTypeInfo(CORINFO_CLASS_HANDLE clsHnd,
                               bool bashStructToRef = false); // converts from jit type representation to typeInfo
      typeInfo verMakeTypeInfo(CorInfoType          ciType,
                               CORINFO_CLASS_HANDLE clsHnd); // converts from jit type representation to typeInfo
      bool verIsSDArray(const typeInfo& ti);
      typeInfo verGetArrayElemType(const typeInfo& ti);
  
      typeInfo verParseArgSigToTypeInfo(CORINFO_SIG_INFO* sig, CORINFO_ARG_LIST_HANDLE args);
      bool verIsByRefLike(const typeInfo& ti);
      bool verIsSafeToReturnByRef(const typeInfo& ti);
  
      // generic type variables range over types that satisfy IsBoxable
      bool verIsBoxable(const typeInfo& ti);
  
      void DECLSPEC_NORETURN verRaiseVerifyException(INDEBUG(const char* reason) DEBUGARG(const char* file)
                                                         DEBUGARG(unsigned line));
      void verRaiseVerifyExceptionIfNeeded(INDEBUG(const char* reason) DEBUGARG(const char* file)
                                               DEBUGARG(unsigned line));
      bool verCheckTailCallConstraint(OPCODE                  opcode,
                                      CORINFO_RESOLVED_TOKEN* pResolvedToken,
                                      CORINFO_RESOLVED_TOKEN* pConstrainedResolvedToken, // Is this a "constrained." call
                                                                                         // on a type parameter?
                                      bool speculative // If true, won't throw if verificatoin fails. Instead it will
                                                       // return false to the caller.
                                                       // If false, it will throw.
                                      );
      bool verIsBoxedValueType(const typeInfo& ti);
  
      void verVerifyCall(OPCODE                  opcode,
                         CORINFO_RESOLVED_TOKEN* pResolvedToken,
                         CORINFO_RESOLVED_TOKEN* pConstrainedResolvedToken,
                         bool                    tailCall,
                         bool                    readonlyCall, // is this a "readonly." call?
                         const BYTE*             delegateCreateStart,
                         const BYTE*             codeAddr,
                         CORINFO_CALL_INFO* callInfo DEBUGARG(const char* methodName));
  
      bool verCheckDelegateCreation(const BYTE* delegateCreateStart, const BYTE* codeAddr, mdMemberRef& targetMemberRef);
  
      typeInfo verVerifySTIND(const typeInfo& ptr, const typeInfo& value, const typeInfo& instrType);
      typeInfo verVerifyLDIND(const typeInfo& ptr, const typeInfo& instrType);
      void verVerifyField(CORINFO_RESOLVED_TOKEN*   pResolvedToken,
                          const CORINFO_FIELD_INFO& fieldInfo,
                          const typeInfo*           tiThis,
                          bool                      mutator,
                          bool                      allowPlainStructAsThis = false);
      void verVerifyCond(const typeInfo& tiOp1, const typeInfo& tiOp2, unsigned opcode);
      void verVerifyThisPtrInitialised();
      bool verIsCallToInitThisPtr(CORINFO_CLASS_HANDLE context, CORINFO_CLASS_HANDLE target);
  
  #ifdef DEBUG
  
      // One line log function. Default level is 0. Increasing it gives you
      // more log information
  
      // levels are currently unused: #define JITDUMP(level,...)                     ();
      void JitLogEE(unsigned level, const char* fmt, ...);
  
      bool compDebugBreak;
  
      bool compJitHaltMethod();
  
  #endif
  
      /*
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XX                                                                           XX
      XX                   GS Security checks for unsafe buffers                   XX
      XX                                                                           XX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      */
  public:
      struct ShadowParamVarInfo
      {
          FixedBitVect* assignGroup; // the closure set of variables whose values depend on each other
          unsigned      shadowCopy;  // Lcl var num, if not valid set to BAD_VAR_NUM
  
          static bool mayNeedShadowCopy(LclVarDsc* varDsc)
          {
  #if defined(TARGET_AMD64)
              // GS cookie logic to create shadow slots, create trees to copy reg args to shadow
              // slots and update all trees to refer to shadow slots is done immediately after
              // fgMorph().  Lsra could potentially mark a param as DoNotEnregister after JIT determines
              // not to shadow a parameter.  Also, LSRA could potentially spill a param which is passed
              // in register. Therefore, conservatively all params may need a shadow copy.  Note that
              // GS cookie logic further checks whether the param is a ptr or an unsafe buffer before
              // creating a shadow slot even though this routine returns true.
              //
              // TODO-AMD64-CQ: Revisit this conservative approach as it could create more shadow slots than
              // required. There are two cases under which a reg arg could potentially be used from its
              // home location:
              //   a) LSRA marks it as DoNotEnregister (see LinearScan::identifyCandidates())
              //   b) LSRA spills it
              //
              // Possible solution to address case (a)
              //   - The conditions under which LSRA marks a varDsc as DoNotEnregister could be checked
              //     in this routine.  Note that live out of exception handler is something we may not be
              //     able to do it here since GS cookie logic is invoked ahead of liveness computation.
              //     Therefore, for methods with exception handling and need GS cookie check we might have
              //     to take conservative approach.
              //
              // Possible solution to address case (b)
              //   - Whenver a parameter passed in an argument register needs to be spilled by LSRA, we
              //     create a new spill temp if the method needs GS cookie check.
              return varDsc->lvIsParam;
  #else // !defined(TARGET_AMD64)
              return varDsc->lvIsParam && !varDsc->lvIsRegArg;
  #endif
          }
  
  #ifdef DEBUG
          void Print()
          {
              printf("assignGroup [%p]; shadowCopy: [%d];\n", assignGroup, shadowCopy);
          }
  #endif
      };
  
      GSCookie*           gsGlobalSecurityCookieAddr; // Address of global cookie for unsafe buffer checks
      GSCookie            gsGlobalSecurityCookieVal;  // Value of global cookie if addr is NULL
      ShadowParamVarInfo* gsShadowVarInfo;            // Table used by shadow param analysis code
  
      void gsGSChecksInitCookie();   // Grabs cookie variable
      void gsCopyShadowParams();     // Identify vulnerable params and create dhadow copies
      bool gsFindVulnerableParams(); // Shadow param analysis code
      void gsParamsToShadows();      // Insert copy code and replave param uses by shadow
  
      static fgWalkPreFn gsMarkPtrsAndAssignGroups; // Shadow param analysis tree-walk
      static fgWalkPreFn gsReplaceShadowParams;     // Shadow param replacement tree-walk
  
  #define DEFAULT_MAX_INLINE_SIZE 100 // Methods with >  DEFAULT_MAX_INLINE_SIZE IL bytes will never be inlined.
                                      // This can be overwritten by setting complus_JITInlineSize env variable.
  
  #define DEFAULT_MAX_INLINE_DEPTH 20 // Methods at more than this level deep will not be inlined
  
  #define DEFAULT_MAX_LOCALLOC_TO_LOCAL_SIZE 32 // fixed locallocs of this size or smaller will convert to local buffers
  
  private:
  #ifdef FEATURE_JIT_METHOD_PERF
      JitTimer*                  pCompJitTimer;         // Timer data structure (by phases) for current compilation.
      static CompTimeSummaryInfo s_compJitTimerSummary; // Summary of the Timer information for the whole run.
  
      static LPCWSTR JitTimeLogCsv();        // Retrieve the file name for CSV from ConfigDWORD.
      static LPCWSTR compJitTimeLogFilename; // If a log file for JIT time is desired, filename to write it to.
  #endif
      void BeginPhase(Phases phase); // Indicate the start of the given phase.
      void EndPhase(Phases phase);   // Indicate the end of the given phase.
  
  #if MEASURE_CLRAPI_CALLS
      // Thin wrappers that call into JitTimer (if present).
      inline void CLRApiCallEnter(unsigned apix);
      inline void CLRApiCallLeave(unsigned apix);
  
  public:
      inline void CLR_API_Enter(API_ICorJitInfo_Names ename);
      inline void CLR_API_Leave(API_ICorJitInfo_Names ename);
  
  private:
  #endif
  
  #if defined(DEBUG) || defined(INLINE_DATA)
      // These variables are associated with maintaining SQM data about compile time.
      unsigned __int64 m_compCyclesAtEndOfInlining; // The thread-virtualized cycle count at the end of the inlining phase
                                                    // in the current compilation.
      unsigned __int64 m_compCycles;                // Net cycle count for current compilation
      DWORD m_compTickCountAtEndOfInlining; // The result of GetTickCount() (# ms since some epoch marker) at the end of
                                            // the inlining phase in the current compilation.
  #endif                                    // defined(DEBUG) || defined(INLINE_DATA)
  
      // Records the SQM-relevant (cycles and tick count).  Should be called after inlining is complete.
      // (We do this after inlining because this marks the last point at which the JIT is likely to cause
      // type-loading and class initialization).
      void RecordStateAtEndOfInlining();
      // Assumes being called at the end of compilation.  Update the SQM state.
      void RecordStateAtEndOfCompilation();
  
  public:
  #if FUNC_INFO_LOGGING
      static LPCWSTR compJitFuncInfoFilename; // If a log file for per-function information is required, this is the
                                              // filename to write it to.
      static FILE* compJitFuncInfoFile;       // And this is the actual FILE* to write to.
  #endif                                      // FUNC_INFO_LOGGING
  
      Compiler* prevCompiler; // Previous compiler on stack for TLS Compiler* linked list for reentrant compilers.
  
  #if MEASURE_NOWAY
      void RecordNowayAssert(const char* filename, unsigned line, const char* condStr);
  #endif // MEASURE_NOWAY
  
  #ifndef FEATURE_TRACELOGGING
      // Should we actually fire the noway assert body and the exception handler?
      bool compShouldThrowOnNoway();
  #else  // FEATURE_TRACELOGGING
      // Should we actually fire the noway assert body and the exception handler?
      bool compShouldThrowOnNoway(const char* filename, unsigned line);
  
      // Telemetry instance to use per method compilation.
      JitTelemetry compJitTelemetry;
  
      // Get common parameters that have to be logged with most telemetry data.
      void compGetTelemetryDefaults(const char** assemblyName,
                                    const char** scopeName,
                                    const char** methodName,
                                    unsigned*    methodHash);
  #endif // !FEATURE_TRACELOGGING
  
  #ifdef DEBUG
  private:
      NodeToTestDataMap* m_nodeTestData;
  
      static const unsigned FIRST_LOOP_HOIST_CSE_CLASS = 1000;
      unsigned              m_loopHoistCSEClass; // LoopHoist test annotations turn into CSE requirements; we
                                                 // label them with CSE Class #'s starting at FIRST_LOOP_HOIST_CSE_CLASS.
                                                 // Current kept in this.
  public:
      NodeToTestDataMap* GetNodeTestData()
      {
          Compiler* compRoot = impInlineRoot();
          if (compRoot->m_nodeTestData == nullptr)
          {
              compRoot->m_nodeTestData = new (getAllocatorDebugOnly()) NodeToTestDataMap(getAllocatorDebugOnly());
          }
          return compRoot->m_nodeTestData;
      }
  
      typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, int> NodeToIntMap;
  
      // Returns the set (i.e., the domain of the result map) of nodes that are keys in m_nodeTestData, and
      // currently occur in the AST graph.
      NodeToIntMap* FindReachableNodesInNodeTestData();
  
      // Node "from" is being eliminated, and being replaced by node "to".  If "from" had any associated
      // test data, associate that data with "to".
      void TransferTestDataToNode(GenTree* from, GenTree* to);
  
      // These are the methods that test that the various conditions implied by the
      // test attributes are satisfied.
      void JitTestCheckSSA(); // SSA builder tests.
      void JitTestCheckVN();  // Value numbering tests.
  #endif                      // DEBUG
  
      // The "FieldSeqStore", for canonicalizing field sequences.  See the definition of FieldSeqStore for
      // operations.
      FieldSeqStore* m_fieldSeqStore;
  
      FieldSeqStore* GetFieldSeqStore()
      {
          Compiler* compRoot = impInlineRoot();
          if (compRoot->m_fieldSeqStore == nullptr)
          {
              // Create a CompAllocator that labels sub-structure with CMK_FieldSeqStore, and use that for allocation.
              CompAllocator ialloc(getAllocator(CMK_FieldSeqStore));
              compRoot->m_fieldSeqStore = new (ialloc) FieldSeqStore(ialloc);
          }
          return compRoot->m_fieldSeqStore;
      }
  
      typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, FieldSeqNode*> NodeToFieldSeqMap;
  
      // Some nodes of "TYP_BYREF" or "TYP_I_IMPL" actually represent the address of a field within a struct, but since
      // the offset of the field is zero, there's no "GT_ADD" node.  We normally attach a field sequence to the constant
      // that is added, but what do we do when that constant is zero, and is thus not present?  We use this mechanism to
      // attach the field sequence directly to the address node.
      NodeToFieldSeqMap* m_zeroOffsetFieldMap;
  
      NodeToFieldSeqMap* GetZeroOffsetFieldMap()
      {
          // Don't need to worry about inlining here
          if (m_zeroOffsetFieldMap == nullptr)
          {
              // Create a CompAllocator that labels sub-structure with CMK_ZeroOffsetFieldMap, and use that for
              // allocation.
              CompAllocator ialloc(getAllocator(CMK_ZeroOffsetFieldMap));
              m_zeroOffsetFieldMap = new (ialloc) NodeToFieldSeqMap(ialloc);
          }
          return m_zeroOffsetFieldMap;
      }
  
      // Requires that "op1" is a node of type "TYP_BYREF" or "TYP_I_IMPL".  We are dereferencing this with the fields in
      // "fieldSeq", whose offsets are required all to be zero.  Ensures that any field sequence annotation currently on
      // "op1" or its components is augmented by appending "fieldSeq".  In practice, if "op1" is a GT_LCL_FLD, it has
      // a field sequence as a member; otherwise, it may be the addition of an a byref and a constant, where the const
      // has a field sequence -- in this case "fieldSeq" is appended to that of the constant; otherwise, we
      // record the the field sequence using the ZeroOffsetFieldMap described above.
      //
      // One exception above is that "op1" is a node of type "TYP_REF" where "op1" is a GT_LCL_VAR.
      // This happens when System.Object vtable pointer is a regular field at offset 0 in System.Private.CoreLib in
      // CoreRT. Such case is handled same as the default case.
      void fgAddFieldSeqForZeroOffset(GenTree* op1, FieldSeqNode* fieldSeq);
  
      typedef JitHashTable<const GenTree*, JitPtrKeyFuncs<GenTree>, ArrayInfo> NodeToArrayInfoMap;
      NodeToArrayInfoMap* m_arrayInfoMap;
  
      NodeToArrayInfoMap* GetArrayInfoMap()
      {
          Compiler* compRoot = impInlineRoot();
          if (compRoot->m_arrayInfoMap == nullptr)
          {
              // Create a CompAllocator that labels sub-structure with CMK_ArrayInfoMap, and use that for allocation.
              CompAllocator ialloc(getAllocator(CMK_ArrayInfoMap));
              compRoot->m_arrayInfoMap = new (ialloc) NodeToArrayInfoMap(ialloc);
          }
          return compRoot->m_arrayInfoMap;
      }
  
      //-----------------------------------------------------------------------------------------------------------------
      // Compiler::TryGetArrayInfo:
      //    Given an indirection node, checks to see whether or not that indirection represents an array access, and
      //    if so returns information about the array.
      //
      // Arguments:
      //    indir           - The `GT_IND` node.
      //    arrayInfo (out) - Information about the accessed array if this function returns true. Undefined otherwise.
      //
      // Returns:
      //    True if the `GT_IND` node represents an array access; false otherwise.
      bool TryGetArrayInfo(GenTreeIndir* indir, ArrayInfo* arrayInfo)
      {
          if ((indir->gtFlags & GTF_IND_ARR_INDEX) == 0)
          {
              return false;
          }
  
          if (indir->gtOp1->OperIs(GT_INDEX_ADDR))
          {
              GenTreeIndexAddr* const indexAddr = indir->gtOp1->AsIndexAddr();
              *arrayInfo = ArrayInfo(indexAddr->gtElemType, indexAddr->gtElemSize, indexAddr->gtElemOffset,
                                     indexAddr->gtStructElemClass);
              return true;
          }
  
          bool found = GetArrayInfoMap()->Lookup(indir, arrayInfo);
          assert(found);
          return true;
      }
  
      NodeToUnsignedMap* m_memorySsaMap[MemoryKindCount];
  
      // In some cases, we want to assign intermediate SSA #'s to memory states, and know what nodes create those memory
      // states. (We do this for try blocks, where, if the try block doesn't do a call that loses track of the memory
      // state, all the possible memory states are possible initial states of the corresponding catch block(s).)
      NodeToUnsignedMap* GetMemorySsaMap(MemoryKind memoryKind)
      {
          if (memoryKind == GcHeap && byrefStatesMatchGcHeapStates)
          {
              // Use the same map for GCHeap and ByrefExposed when their states match.
              memoryKind = ByrefExposed;
          }
  
          assert(memoryKind < MemoryKindCount);
          Compiler* compRoot = impInlineRoot();
          if (compRoot->m_memorySsaMap[memoryKind] == nullptr)
          {
              // Create a CompAllocator that labels sub-structure with CMK_ArrayInfoMap, and use that for allocation.
              CompAllocator ialloc(getAllocator(CMK_ArrayInfoMap));
              compRoot->m_memorySsaMap[memoryKind] = new (ialloc) NodeToUnsignedMap(ialloc);
          }
          return compRoot->m_memorySsaMap[memoryKind];
      }
  
      // The Refany type is the only struct type whose structure is implicitly assumed by IL.  We need its fields.
      CORINFO_CLASS_HANDLE m_refAnyClass;
      CORINFO_FIELD_HANDLE GetRefanyDataField()
      {
          if (m_refAnyClass == nullptr)
          {
              m_refAnyClass = info.compCompHnd->getBuiltinClass(CLASSID_TYPED_BYREF);
          }
          return info.compCompHnd->getFieldInClass(m_refAnyClass, 0);
      }
      CORINFO_FIELD_HANDLE GetRefanyTypeField()
      {
          if (m_refAnyClass == nullptr)
          {
              m_refAnyClass = info.compCompHnd->getBuiltinClass(CLASSID_TYPED_BYREF);
          }
          return info.compCompHnd->getFieldInClass(m_refAnyClass, 1);
      }
  
  #if VARSET_COUNTOPS
      static BitSetSupport::BitSetOpCounter m_varsetOpCounter;
  #endif
  #if ALLVARSET_COUNTOPS
      static BitSetSupport::BitSetOpCounter m_allvarsetOpCounter;
  #endif
  
      static HelperCallProperties s_helperCallProperties;
  
  #ifdef UNIX_AMD64_ABI
      static var_types GetTypeFromClassificationAndSizes(SystemVClassificationType classType, int size);
      static var_types GetEightByteType(const SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR& structDesc,
                                        unsigned                                                   slotNum);
  
      static void GetStructTypeOffset(const SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR& structDesc,
                                      var_types*                                                 type0,
                                      var_types*                                                 type1,
                                      unsigned __int8*                                           offset0,
                                      unsigned __int8*                                           offset1);
  
      void GetStructTypeOffset(CORINFO_CLASS_HANDLE typeHnd,
                               var_types*           type0,
                               var_types*           type1,
                               unsigned __int8*     offset0,
                               unsigned __int8*     offset1);
  
  #endif // defined(UNIX_AMD64_ABI)
  
      void fgMorphMultiregStructArgs(GenTreeCall* call);
      GenTree* fgMorphMultiregStructArg(GenTree* arg, fgArgTabEntry* fgEntryPtr);
  
      bool killGCRefs(GenTree* tree);
  }; // end of class Compiler
  
  //---------------------------------------------------------------------------------------------------------------------
  // GenTreeVisitor: a flexible tree walker implemented using the curiously-recurring-template pattern.
  //
  // This class implements a configurable walker for IR trees. There are five configuration options (defaults values are
  // shown in parentheses):
  //
  // - ComputeStack (false): when true, the walker will push each node onto the `m_ancestors` stack. "Ancestors" is a bit
  //                         of a misnomer, as the first entry will always be the current node.
  //
  // - DoPreOrder (false): when true, the walker will invoke `TVisitor::PreOrderVisit` with the current node as an
  //                       argument before visiting the node's operands.
  //
  // - DoPostOrder (false): when true, the walker will invoke `TVisitor::PostOrderVisit` with the current node as an
  //                        argument after visiting the node's operands.
  //
  // - DoLclVarsOnly (false): when true, the walker will only invoke `TVisitor::PreOrderVisit` for lclVar nodes.
  //                          `DoPreOrder` must be true if this option is true.
  //
  // - UseExecutionOrder (false): when true, then walker will visit a node's operands in execution order (e.g. if a
  //                              binary operator has the `GTF_REVERSE_OPS` flag set, the second operand will be
  //                              visited before the first).
  //
  // At least one of `DoPreOrder` and `DoPostOrder` must be specified.
  //
  // A simple pre-order visitor might look something like the following:
  //
  //     class CountingVisitor final : public GenTreeVisitor<CountingVisitor>
  //     {
  //     public:
  //         enum
  //         {
  //             DoPreOrder = true
  //         };
  //
  //         unsigned m_count;
  //
  //         CountingVisitor(Compiler* compiler)
  //             : GenTreeVisitor<CountingVisitor>(compiler), m_count(0)
  //         {
  //         }
  //
  //         Compiler::fgWalkResult PreOrderVisit(GenTree* node)
  //         {
  //             m_count++;
  //         }
  //     };
  //
  // This visitor would then be used like so:
  //
  //     CountingVisitor countingVisitor(compiler);
  //     countingVisitor.WalkTree(root);
  //
  template <typename TVisitor>
  class GenTreeVisitor
  {
  protected:
      typedef Compiler::fgWalkResult fgWalkResult;
  
      enum
      {
          ComputeStack      = false,
          DoPreOrder        = false,
          DoPostOrder       = false,
          DoLclVarsOnly     = false,
          UseExecutionOrder = false,
      };
  
      Compiler*            m_compiler;
      ArrayStack<GenTree*> m_ancestors;
  
      GenTreeVisitor(Compiler* compiler) : m_compiler(compiler), m_ancestors(compiler->getAllocator(CMK_ArrayStack))
      {
          assert(compiler != nullptr);
  
          static_assert_no_msg(TVisitor::DoPreOrder || TVisitor::DoPostOrder);
          static_assert_no_msg(!TVisitor::DoLclVarsOnly || TVisitor::DoPreOrder);
      }
  
      fgWalkResult PreOrderVisit(GenTree** use, GenTree* user)
      {
          return fgWalkResult::WALK_CONTINUE;
      }
  
      fgWalkResult PostOrderVisit(GenTree** use, GenTree* user)
      {
          return fgWalkResult::WALK_CONTINUE;
      }
  
  public:
      fgWalkResult WalkTree(GenTree** use, GenTree* user)
      {
          assert(use != nullptr);
  
          GenTree* node = *use;
  
          if (TVisitor::ComputeStack)
          {
              m_ancestors.Push(node);
          }
  
          fgWalkResult result = fgWalkResult::WALK_CONTINUE;
          if (TVisitor::DoPreOrder && !TVisitor::DoLclVarsOnly)
          {
              result = reinterpret_cast<TVisitor*>(this)->PreOrderVisit(use, user);
              if (result == fgWalkResult::WALK_ABORT)
              {
                  return result;
              }
  
              node = *use;
              if ((node == nullptr) || (result == fgWalkResult::WALK_SKIP_SUBTREES))
              {
                  goto DONE;
              }
          }
  
          switch (node->OperGet())
          {
              // Leaf lclVars
              case GT_LCL_VAR:
              case GT_LCL_FLD:
              case GT_LCL_VAR_ADDR:
              case GT_LCL_FLD_ADDR:
                  if (TVisitor::DoLclVarsOnly)
                  {
                      result = reinterpret_cast<TVisitor*>(this)->PreOrderVisit(use, user);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  FALLTHROUGH;
  
              // Leaf nodes
              case GT_CATCH_ARG:
              case GT_LABEL:
              case GT_FTN_ADDR:
              case GT_RET_EXPR:
              case GT_CNS_INT:
              case GT_CNS_LNG:
              case GT_CNS_DBL:
              case GT_CNS_STR:
              case GT_MEMORYBARRIER:
              case GT_JMP:
              case GT_JCC:
              case GT_SETCC:
              case GT_NO_OP:
              case GT_START_NONGC:
              case GT_START_PREEMPTGC:
              case GT_PROF_HOOK:
  #if !defined(FEATURE_EH_FUNCLETS)
              case GT_END_LFIN:
  #endif // !FEATURE_EH_FUNCLETS
              case GT_PHI_ARG:
              case GT_JMPTABLE:
              case GT_CLS_VAR:
              case GT_CLS_VAR_ADDR:
              case GT_ARGPLACE:
              case GT_PHYSREG:
              case GT_EMITNOP:
              case GT_PINVOKE_PROLOG:
              case GT_PINVOKE_EPILOG:
              case GT_IL_OFFSET:
                  break;
  
              // Lclvar unary operators
              case GT_STORE_LCL_VAR:
              case GT_STORE_LCL_FLD:
                  if (TVisitor::DoLclVarsOnly)
                  {
                      result = reinterpret_cast<TVisitor*>(this)->PreOrderVisit(use, user);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  FALLTHROUGH;
  
              // Standard unary operators
              case GT_NOT:
              case GT_NEG:
              case GT_BSWAP:
              case GT_BSWAP16:
              case GT_COPY:
              case GT_RELOAD:
              case GT_ARR_LENGTH:
              case GT_CAST:
              case GT_BITCAST:
              case GT_CKFINITE:
              case GT_LCLHEAP:
              case GT_ADDR:
              case GT_IND:
              case GT_OBJ:
              case GT_BLK:
              case GT_BOX:
              case GT_ALLOCOBJ:
              case GT_INIT_VAL:
              case GT_JTRUE:
              case GT_SWITCH:
              case GT_NULLCHECK:
              case GT_PUTARG_REG:
              case GT_PUTARG_STK:
              case GT_PUTARG_TYPE:
              case GT_RETURNTRAP:
              case GT_NOP:
              case GT_FIELD:
              case GT_RETURN:
              case GT_RETFILT:
              case GT_RUNTIMELOOKUP:
              case GT_KEEPALIVE:
              case GT_INC_SATURATE:
              {
                  GenTreeUnOp* const unOp = node->AsUnOp();
                  if (unOp->gtOp1 != nullptr)
                  {
                      result = WalkTree(&unOp->gtOp1, unOp);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  break;
              }
  
              // Special nodes
              case GT_PHI:
                  for (GenTreePhi::Use& use : node->AsPhi()->Uses())
                  {
                      result = WalkTree(&use.NodeRef(), node);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  break;
  
              case GT_FIELD_LIST:
                  for (GenTreeFieldList::Use& use : node->AsFieldList()->Uses())
                  {
                      result = WalkTree(&use.NodeRef(), node);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  break;
  
              case GT_CMPXCHG:
              {
                  GenTreeCmpXchg* const cmpXchg = node->AsCmpXchg();
  
                  result = WalkTree(&cmpXchg->gtOpLocation, cmpXchg);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  result = WalkTree(&cmpXchg->gtOpValue, cmpXchg);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  result = WalkTree(&cmpXchg->gtOpComparand, cmpXchg);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  break;
              }
  
              case GT_ARR_ELEM:
              {
                  GenTreeArrElem* const arrElem = node->AsArrElem();
  
                  result = WalkTree(&arrElem->gtArrObj, arrElem);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
  
                  const unsigned rank = arrElem->gtArrRank;
                  for (unsigned dim = 0; dim < rank; dim++)
                  {
                      result = WalkTree(&arrElem->gtArrInds[dim], arrElem);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  break;
              }
  
              case GT_ARR_OFFSET:
              {
                  GenTreeArrOffs* const arrOffs = node->AsArrOffs();
  
                  result = WalkTree(&arrOffs->gtOffset, arrOffs);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  result = WalkTree(&arrOffs->gtIndex, arrOffs);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  result = WalkTree(&arrOffs->gtArrObj, arrOffs);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  break;
              }
  
              case GT_STORE_DYN_BLK:
              {
                  GenTreeStoreDynBlk* const dynBlock = node->AsStoreDynBlk();
  
                  GenTree** op1Use = &dynBlock->gtOp1;
                  GenTree** op2Use = &dynBlock->gtOp2;
                  GenTree** op3Use = &dynBlock->gtDynamicSize;
  
                  result = WalkTree(op1Use, dynBlock);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  result = WalkTree(op2Use, dynBlock);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  result = WalkTree(op3Use, dynBlock);
                  if (result == fgWalkResult::WALK_ABORT)
                  {
                      return result;
                  }
                  break;
              }
  
              case GT_CALL:
              {
                  GenTreeCall* const call = node->AsCall();
  
                  if (call->gtCallThisArg != nullptr)
                  {
                      result = WalkTree(&call->gtCallThisArg->NodeRef(), call);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
  
                  for (GenTreeCall::Use& use : call->Args())
                  {
                      result = WalkTree(&use.NodeRef(), call);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
  
                  for (GenTreeCall::Use& use : call->LateArgs())
                  {
                      result = WalkTree(&use.NodeRef(), call);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
  
                  if (call->gtCallType == CT_INDIRECT)
                  {
                      if (call->gtCallCookie != nullptr)
                      {
                          result = WalkTree(&call->gtCallCookie, call);
                          if (result == fgWalkResult::WALK_ABORT)
                          {
                              return result;
                          }
                      }
  
                      result = WalkTree(&call->gtCallAddr, call);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
  
                  if (call->gtControlExpr != nullptr)
                  {
                      result = WalkTree(&call->gtControlExpr, call);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
  
                  break;
              }
  
  #if defined(FEATURE_SIMD) || defined(FEATURE_HW_INTRINSICS)
  #if defined(FEATURE_SIMD)
              case GT_SIMD:
  #endif
  #if defined(FEATURE_HW_INTRINSICS)
              case GT_HWINTRINSIC:
  #endif
                  if (TVisitor::UseExecutionOrder && node->IsReverseOp())
                  {
                      assert(node->AsMultiOp()->GetOperandCount() == 2);
  
                      result = WalkTree(&node->AsMultiOp()->Op(2), node);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                      result = WalkTree(&node->AsMultiOp()->Op(1), node);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  else
                  {
                      for (GenTree** use : node->AsMultiOp()->UseEdges())
                      {
                          result = WalkTree(use, node);
                          if (result == fgWalkResult::WALK_ABORT)
                          {
                              return result;
                          }
                      }
                  }
                  break;
  #endif // defined(FEATURE_SIMD) || defined(FEATURE_HW_INTRINSICS)
  
              // Binary nodes
              default:
              {
                  assert(node->OperIsBinary());
  
                  GenTreeOp* const op = node->AsOp();
  
                  GenTree** op1Use = &op->gtOp1;
                  GenTree** op2Use = &op->gtOp2;
  
                  if (TVisitor::UseExecutionOrder && node->IsReverseOp())
                  {
                      std::swap(op1Use, op2Use);
                  }
  
                  if (*op1Use != nullptr)
                  {
                      result = WalkTree(op1Use, op);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
  
                  if (*op2Use != nullptr)
                  {
                      result = WalkTree(op2Use, op);
                      if (result == fgWalkResult::WALK_ABORT)
                      {
                          return result;
                      }
                  }
                  break;
              }
          }
  
      DONE:
          // Finally, visit the current node
          if (TVisitor::DoPostOrder)
          {
              result = reinterpret_cast<TVisitor*>(this)->PostOrderVisit(use, user);
          }
  
          if (TVisitor::ComputeStack)
          {
              m_ancestors.Pop();
          }
  
          return result;
      }
  };
  
  template <bool computeStack, bool doPreOrder, bool doPostOrder, bool doLclVarsOnly, bool useExecutionOrder>
  class GenericTreeWalker final
      : public GenTreeVisitor<GenericTreeWalker<computeStack, doPreOrder, doPostOrder, doLclVarsOnly, useExecutionOrder>>
  {
  public:
      enum
      {
          ComputeStack      = computeStack,
          DoPreOrder        = doPreOrder,
          DoPostOrder       = doPostOrder,
          DoLclVarsOnly     = doLclVarsOnly,
          UseExecutionOrder = useExecutionOrder,
      };
  
  private:
      Compiler::fgWalkData* m_walkData;
  
  public:
      GenericTreeWalker(Compiler::fgWalkData* walkData)
          : GenTreeVisitor<GenericTreeWalker<computeStack, doPreOrder, doPostOrder, doLclVarsOnly, useExecutionOrder>>(
                walkData->compiler)
          , m_walkData(walkData)
      {
          assert(walkData != nullptr);
  
          if (computeStack)
          {
              walkData->parentStack = &this->m_ancestors;
          }
      }
  
      Compiler::fgWalkResult PreOrderVisit(GenTree** use, GenTree* user)
      {
          m_walkData->parent = user;
          return m_walkData->wtprVisitorFn(use, m_walkData);
      }
  
      Compiler::fgWalkResult PostOrderVisit(GenTree** use, GenTree* user)
      {
          m_walkData->parent = user;
          return m_walkData->wtpoVisitorFn(use, m_walkData);
      }
  };
  
  // A dominator tree visitor implemented using the curiously-recurring-template pattern, similar to GenTreeVisitor.
  template <typename TVisitor>
  class DomTreeVisitor
  {
  protected:
      Compiler* const    m_compiler;
      DomTreeNode* const m_domTree;
  
      DomTreeVisitor(Compiler* compiler, DomTreeNode* domTree) : m_compiler(compiler), m_domTree(domTree)
      {
      }
  
      void Begin()
      {
      }
  
      void PreOrderVisit(BasicBlock* block)
      {
      }
  
      void PostOrderVisit(BasicBlock* block)
      {
      }
  
      void End()
      {
      }
  
  public:
      //------------------------------------------------------------------------
      // WalkTree: Walk the dominator tree, starting from fgFirstBB.
      //
      // Notes:
      //    This performs a non-recursive, non-allocating walk of the tree by using
      //    DomTreeNode's firstChild and nextSibling links to locate the children of
      //    a node and BasicBlock's bbIDom parent link to go back up the tree when
      //    no more children are left.
      //
      //    Forests are also supported, provided that all the roots are chained via
      //    DomTreeNode::nextSibling to fgFirstBB.
      //
      void WalkTree()
      {
          static_cast<TVisitor*>(this)->Begin();
  
          for (BasicBlock *next, *block = m_compiler->fgFirstBB; block != nullptr; block = next)
          {
              static_cast<TVisitor*>(this)->PreOrderVisit(block);
  
              next = m_domTree[block->bbNum].firstChild;
  
              if (next != nullptr)
              {
                  assert(next->bbIDom == block);
                  continue;
              }
  
              do
              {
                  static_cast<TVisitor*>(this)->PostOrderVisit(block);
  
                  next = m_domTree[block->bbNum].nextSibling;
  
                  if (next != nullptr)
                  {
                      assert(next->bbIDom == block->bbIDom);
                      break;
                  }
  
                  block = block->bbIDom;
  
              } while (block != nullptr);
          }
  
          static_cast<TVisitor*>(this)->End();
      }
  };
  
  // EHClauses: adapter class for forward iteration of the exception handling table using range-based `for`, e.g.:
  //    for (EHblkDsc* const ehDsc : EHClauses(compiler))
  //
  class EHClauses
  {
      EHblkDsc* m_begin;
      EHblkDsc* m_end;
  
      // Forward iterator for the exception handling table entries. Iteration is in table order.
      //
      class iterator
      {
          EHblkDsc* m_ehDsc;
  
      public:
          iterator(EHblkDsc* ehDsc) : m_ehDsc(ehDsc)
          {
          }
  
          EHblkDsc* operator*() const
          {
              return m_ehDsc;
          }
  
          iterator& operator++()
          {
              ++m_ehDsc;
              return *this;
          }
  
          bool operator!=(const iterator& i) const
          {
              return m_ehDsc != i.m_ehDsc;
          }
      };
  
  public:
      EHClauses(Compiler* comp) : m_begin(comp->compHndBBtab), m_end(comp->compHndBBtab + comp->compHndBBtabCount)
      {
          assert((m_begin != nullptr) || (m_begin == m_end));
      }
  
      iterator begin() const
      {
          return iterator(m_begin);
      }
  
      iterator end() const
      {
          return iterator(m_end);
      }
  };
  
  /*
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XX                                                                           XX
  XX                   Miscellaneous Compiler stuff                            XX
  XX                                                                           XX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  */
  
  // Values used to mark the types a stack slot is used for
  
  const unsigned TYPE_REF_INT      = 0x01; // slot used as a 32-bit int
  const unsigned TYPE_REF_LNG      = 0x02; // slot used as a 64-bit long
  const unsigned TYPE_REF_FLT      = 0x04; // slot used as a 32-bit float
  const unsigned TYPE_REF_DBL      = 0x08; // slot used as a 64-bit float
  const unsigned TYPE_REF_PTR      = 0x10; // slot used as a 32-bit pointer
  const unsigned TYPE_REF_BYR      = 0x20; // slot used as a byref pointer
  const unsigned TYPE_REF_STC      = 0x40; // slot used as a struct
  const unsigned TYPE_REF_TYPEMASK = 0x7F; // bits that represent the type
  
  // const unsigned TYPE_REF_ADDR_TAKEN  = 0x80; // slots address was taken
  
  /*****************************************************************************
   *
   *  Variables to keep track of total code amounts.
   */
  
  #if DISPLAY_SIZES
  
  extern size_t grossVMsize;
  extern size_t grossNCsize;
  extern size_t totalNCsize;
  
  extern unsigned genMethodICnt;
  extern unsigned genMethodNCnt;
  extern size_t   gcHeaderISize;
  extern size_t   gcPtrMapISize;
  extern size_t   gcHeaderNSize;
  extern size_t   gcPtrMapNSize;
  
  #endif // DISPLAY_SIZES
  
  /*****************************************************************************
   *
   *  Variables to keep track of basic block counts (more data on 1 BB methods)
   */
  
  #if COUNT_BASIC_BLOCKS
  extern Histogram bbCntTable;
  extern Histogram bbOneBBSizeTable;
  #endif
  
  /*****************************************************************************
   *
   *  Used by optFindNaturalLoops to gather statistical information such as
   *   - total number of natural loops
   *   - number of loops with 1, 2, ... exit conditions
   *   - number of loops that have an iterator (for like)
   *   - number of loops that have a constant iterator
   */
  
  #if COUNT_LOOPS
  
  extern unsigned totalLoopMethods;        // counts the total number of methods that have natural loops
  extern unsigned maxLoopsPerMethod;       // counts the maximum number of loops a method has
  extern unsigned totalLoopOverflows;      // # of methods that identified more loops than we can represent
  extern unsigned totalLoopCount;          // counts the total number of natural loops
  extern unsigned totalUnnatLoopCount;     // counts the total number of (not-necessarily natural) loops
  extern unsigned totalUnnatLoopOverflows; // # of methods that identified more unnatural loops than we can represent
  extern unsigned iterLoopCount;           // counts the # of loops with an iterator (for like)
  extern unsigned simpleTestLoopCount;     // counts the # of loops with an iterator and a simple loop condition (iter <
                                           // const)
  extern unsigned  constIterLoopCount;     // counts the # of loops with a constant iterator (for like)
  extern bool      hasMethodLoops;         // flag to keep track if we already counted a method as having loops
  extern unsigned  loopsThisMethod;        // counts the number of loops in the current method
  extern bool      loopOverflowThisMethod; // True if we exceeded the max # of loops in the method.
  extern Histogram loopCountTable;         // Histogram of loop counts
  extern Histogram loopExitCountTable;     // Histogram of loop exit counts
  
  #endif // COUNT_LOOPS
  
  /*****************************************************************************
   * variables to keep track of how many iterations we go in a dataflow pass
   */
  
  #if DATAFLOW_ITER
  
  extern unsigned CSEiterCount; // counts the # of iteration for the CSE dataflow
  extern unsigned CFiterCount;  // counts the # of iteration for the Const Folding dataflow
  
  #endif // DATAFLOW_ITER
  
  #if MEASURE_BLOCK_SIZE
  extern size_t genFlowNodeSize;
  extern size_t genFlowNodeCnt;
  #endif // MEASURE_BLOCK_SIZE
  
  #if MEASURE_NODE_SIZE
  struct NodeSizeStats
  {
      void Init()
      {
          genTreeNodeCnt        = 0;
          genTreeNodeSize       = 0;
          genTreeNodeActualSize = 0;
      }
  
      // Count of tree nodes allocated.
      unsigned __int64 genTreeNodeCnt;
  
      // The size we allocate.
      unsigned __int64 genTreeNodeSize;
  
      // The actual size of the node. Note that the actual size will likely be smaller
      // than the allocated size, but we sometimes use SetOper()/ChangeOper() to change
      // a smaller node to a larger one. TODO-Cleanup: add stats on
      // SetOper()/ChangeOper() usage to quantify this.
      unsigned __int64 genTreeNodeActualSize;
  };
  extern NodeSizeStats genNodeSizeStats;        // Total node size stats
  extern NodeSizeStats genNodeSizeStatsPerFunc; // Per-function node size stats
  extern Histogram     genTreeNcntHist;
  extern Histogram     genTreeNsizHist;
  #endif // MEASURE_NODE_SIZE
  
  /*****************************************************************************
   *  Count fatal errors (including noway_asserts).
   */
  
  #if MEASURE_FATAL
  extern unsigned fatal_badCode;
  extern unsigned fatal_noWay;
  extern unsigned fatal_implLimitation;
  extern unsigned fatal_NOMEM;
  extern unsigned fatal_noWayAssertBody;
  #ifdef DEBUG
  extern unsigned fatal_noWayAssertBodyArgs;
  #endif // DEBUG
  extern unsigned fatal_NYI;
  #endif // MEASURE_FATAL
  
  /*****************************************************************************
   * Codegen
   */
  
  #ifdef TARGET_XARCH
  
  const instruction INS_SHIFT_LEFT_LOGICAL  = INS_shl;
  const instruction INS_SHIFT_RIGHT_LOGICAL = INS_shr;
  const instruction INS_SHIFT_RIGHT_ARITHM  = INS_sar;
  
  const instruction INS_AND             = INS_and;
  const instruction INS_OR              = INS_or;
  const instruction INS_XOR             = INS_xor;
  const instruction INS_NEG             = INS_neg;
  const instruction INS_TEST            = INS_test;
  const instruction INS_MUL             = INS_imul;
  const instruction INS_SIGNED_DIVIDE   = INS_idiv;
  const instruction INS_UNSIGNED_DIVIDE = INS_div;
  const instruction INS_BREAKPOINT      = INS_int3;
  const instruction INS_ADDC            = INS_adc;
  const instruction INS_SUBC            = INS_sbb;
  const instruction INS_NOT             = INS_not;
  
  #endif // TARGET_XARCH
  
  #ifdef TARGET_ARM
  
  const instruction INS_SHIFT_LEFT_LOGICAL  = INS_lsl;
  const instruction INS_SHIFT_RIGHT_LOGICAL = INS_lsr;
  const instruction INS_SHIFT_RIGHT_ARITHM  = INS_asr;
  
  const instruction INS_AND             = INS_and;
  const instruction INS_OR              = INS_orr;
  const instruction INS_XOR             = INS_eor;
  const instruction INS_NEG             = INS_rsb;
  const instruction INS_TEST            = INS_tst;
  const instruction INS_MUL             = INS_mul;
  const instruction INS_MULADD          = INS_mla;
  const instruction INS_SIGNED_DIVIDE   = INS_sdiv;
  const instruction INS_UNSIGNED_DIVIDE = INS_udiv;
  const instruction INS_BREAKPOINT      = INS_bkpt;
  const instruction INS_ADDC            = INS_adc;
  const instruction INS_SUBC            = INS_sbc;
  const instruction INS_NOT             = INS_mvn;
  
  const instruction INS_ABS  = INS_vabs;
  const instruction INS_SQRT = INS_vsqrt;
  
  #endif // TARGET_ARM
  
  #ifdef TARGET_ARM64
  
  const instruction        INS_MULADD = INS_madd;
  inline const instruction INS_BREAKPOINT_osHelper()
  {
      // GDB needs the encoding of brk #0
      // Windbg needs the encoding of brk #F000
      return TargetOS::IsUnix ? INS_brk_unix : INS_brk_windows;
  }
  #define INS_BREAKPOINT INS_BREAKPOINT_osHelper()
  
  const instruction INS_ABS  = INS_fabs;
  const instruction INS_SQRT = INS_fsqrt;
  
  #endif // TARGET_ARM64
  
  /*****************************************************************************/
  
  extern const BYTE genTypeSizes[];
  extern const BYTE genTypeAlignments[];
  extern const BYTE genTypeStSzs[];
  extern const BYTE genActualTypes[];
  
  /*****************************************************************************/
  
  #ifdef DEBUG
  void dumpConvertedVarSet(Compiler* comp, VARSET_VALARG_TP vars);
  #endif // DEBUG
  
  #include "compiler.hpp" // All the shared inline functions
  
  /*****************************************************************************/
  #endif //_COMPILER_H_
  /*****************************************************************************/
  