text: //===- CodeGen/Analysis.h - CodeGen LLVM IR Analysis Utilities --*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file declares several CodeGen-specific LLVM IR analysis utilities.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_CODEGEN_ANALYSIS_H
  #define LLVM_CODEGEN_ANALYSIS_H
  
  #include "llvm/ADT/ArrayRef.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/CodeGen/ISDOpcodes.h"
  #include "llvm/IR/CallSite.h"
  #include "llvm/IR/InlineAsm.h"
  #include "llvm/IR/Instructions.h"
  
  namespace llvm {
  class GlobalVariable;
  class TargetLoweringBase;
  class TargetLowering;
  class TargetMachine;
  class SDNode;
  class SDValue;
  class SelectionDAG;
  struct EVT;
  
  /// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
  /// of insertvalue or extractvalue indices that identify a member, return
  /// the linearized index of the start of the member.
  ///
  unsigned ComputeLinearIndex(Type *Ty,
                              const unsigned *Indices,
                              const unsigned *IndicesEnd,
                              unsigned CurIndex = 0);
  
  inline unsigned ComputeLinearIndex(Type *Ty,
                                     ArrayRef<unsigned> Indices,
                                     unsigned CurIndex = 0) {
    return ComputeLinearIndex(Ty, Indices.begin(), Indices.end(), CurIndex);
  }
  
  /// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
  /// EVTs that represent all the individual underlying
  /// non-aggregate types that comprise it.
  ///
  /// If Offsets is non-null, it points to a vector to be filled in
  /// with the in-memory offsets of each of the individual values.
  ///
  void ComputeValueVTs(const TargetLowering &TLI, Type *Ty,
                       SmallVectorImpl<EVT> &ValueVTs,
                       SmallVectorImpl<uint64_t> *Offsets = nullptr,
                       uint64_t StartingOffset = 0);
  
  /// ExtractTypeInfo - Returns the type info, possibly bitcast, encoded in V.
  GlobalVariable *ExtractTypeInfo(Value *V);
  
  /// hasInlineAsmMemConstraint - Return true if the inline asm instruction being
  /// processed uses a memory 'm' constraint.
  bool hasInlineAsmMemConstraint(InlineAsm::ConstraintInfoVector &CInfos,
                                 const TargetLowering &TLI);
  
  /// getFCmpCondCode - Return the ISD condition code corresponding to
  /// the given LLVM IR floating-point condition code.  This includes
  /// consideration of global floating-point math flags.
  ///
  ISD::CondCode getFCmpCondCode(FCmpInst::Predicate Pred);
  
  /// getFCmpCodeWithoutNaN - Given an ISD condition code comparing floats,
  /// return the equivalent code if we're allowed to assume that NaNs won't occur.
  ISD::CondCode getFCmpCodeWithoutNaN(ISD::CondCode CC);
  
  /// getICmpCondCode - Return the ISD condition code corresponding to
  /// the given LLVM IR integer condition code.
  ///
  ISD::CondCode getICmpCondCode(ICmpInst::Predicate Pred);
  
  /// Test if the given instruction is in a position to be optimized
  /// with a tail-call. This roughly means that it's in a block with
  /// a return and there's nothing that needs to be scheduled
  /// between it and the return.
  ///
  /// This function only tests target-independent requirements.
  bool isInTailCallPosition(ImmutableCallSite CS, const TargetMachine &TM);
  
  /// Test if given that the input instruction is in the tail call position if the
  /// return type or any attributes of the function will inhibit tail call
  /// optimization.
  bool returnTypeIsEligibleForTailCall(const Function *F,
                                       const Instruction *I,
                                       const ReturnInst *Ret,
                                       const TargetLoweringBase &TLI);
  
  } // End llvm namespace
  
  #endif
  