text: //===-- Instructions.cpp - Implement the LLVM instructions ----------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file implements all of the non-inline methods for the LLVM instruction
  // classes.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/IR/Instructions.h"
  #include "LLVMContextImpl.h"
  #include "llvm/IR/CallSite.h"
  #include "llvm/IR/ConstantRange.h"
  #include "llvm/IR/Constants.h"
  #include "llvm/IR/DataLayout.h"
  #include "llvm/IR/DerivedTypes.h"
  #include "llvm/IR/Function.h"
  #include "llvm/IR/Module.h"
  #include "llvm/IR/Operator.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/MathExtras.h"
  using namespace llvm;
  
  //===----------------------------------------------------------------------===//
  //                            CallSite Class
  //===----------------------------------------------------------------------===//
  
  User::op_iterator CallSite::getCallee() const {
    Instruction *II(getInstruction());
    return isCall()
      ? cast<CallInst>(II)->op_end() - 1 // Skip Callee
      : cast<InvokeInst>(II)->op_end() - 3; // Skip BB, BB, Callee
  }
  
  //===----------------------------------------------------------------------===//
  //                            TerminatorInst Class
  //===----------------------------------------------------------------------===//
  
  // Out of line virtual method, so the vtable, etc has a home.
  TerminatorInst::~TerminatorInst() {
  }
  
  //===----------------------------------------------------------------------===//
  //                           UnaryInstruction Class
  //===----------------------------------------------------------------------===//
  
  // Out of line virtual method, so the vtable, etc has a home.
  UnaryInstruction::~UnaryInstruction() {
  }
  
  //===----------------------------------------------------------------------===//
  //                              SelectInst Class
  //===----------------------------------------------------------------------===//
  
  /// areInvalidOperands - Return a string if the specified operands are invalid
  /// for a select operation, otherwise return null.
  const char *SelectInst::areInvalidOperands(Value *Op0, Value *Op1, Value *Op2) {
    if (Op1->getType() != Op2->getType())
      return "both values to select must have same type";
    
    if (VectorType *VT = dyn_cast<VectorType>(Op0->getType())) {
      // Vector select.
      if (VT->getElementType() != Type::getInt1Ty(Op0->getContext()))
        return "vector select condition element type must be i1";
      VectorType *ET = dyn_cast<VectorType>(Op1->getType());
      if (!ET)
        return "selected values for vector select must be vectors";
      if (ET->getNumElements() != VT->getNumElements())
        return "vector select requires selected vectors to have "
                     "the same vector length as select condition";
    } else if (Op0->getType() != Type::getInt1Ty(Op0->getContext())) {
      return "select condition must be i1 or <n x i1>";
    }
    return nullptr;
  }
  
  
  //===----------------------------------------------------------------------===//
  //                               PHINode Class
  //===----------------------------------------------------------------------===//
  
  PHINode::PHINode(const PHINode &PN)
      : Instruction(PN.getType(), Instruction::PHI, nullptr, PN.getNumOperands()),
        ReservedSpace(PN.getNumOperands()) {
    allocHungoffUses(PN.getNumOperands());
    std::copy(PN.op_begin(), PN.op_end(), op_begin());
    std::copy(PN.block_begin(), PN.block_end(), block_begin());
    SubclassOptionalData = PN.SubclassOptionalData;
  }
  
  // removeIncomingValue - Remove an incoming value.  This is useful if a
  // predecessor basic block is deleted.
  Value *PHINode::removeIncomingValue(unsigned Idx, bool DeletePHIIfEmpty) {
    Value *Removed = getIncomingValue(Idx);
  
    // Move everything after this operand down.
    //
    // FIXME: we could just swap with the end of the list, then erase.  However,
    // clients might not expect this to happen.  The code as it is thrashes the
    // use/def lists, which is kinda lame.
    std::copy(op_begin() + Idx + 1, op_end(), op_begin() + Idx);
    std::copy(block_begin() + Idx + 1, block_end(), block_begin() + Idx);
  
    // Nuke the last value.
    Op<-1>().set(nullptr);
    setNumHungOffUseOperands(getNumOperands() - 1);
  
    // If the PHI node is dead, because it has zero entries, nuke it now.
    if (getNumOperands() == 0 && DeletePHIIfEmpty) {
      // If anyone is using this PHI, make them use a dummy value instead...
      replaceAllUsesWith(UndefValue::get(getType()));
      eraseFromParent();
    }
    return Removed;
  }
  
  /// growOperands - grow operands - This grows the operand list in response
  /// to a push_back style of operation.  This grows the number of ops by 1.5
  /// times.
  ///
  void PHINode::growOperands() {
    unsigned e = getNumOperands();
    unsigned NumOps = e + e / 2;
    if (NumOps < 2) NumOps = 2;      // 2 op PHI nodes are VERY common.
  
    ReservedSpace = NumOps;
    growHungoffUses(ReservedSpace, /* IsPhi */ true);
  }
  
  /// hasConstantValue - If the specified PHI node always merges together the same
  /// value, return the value, otherwise return null.
  Value *PHINode::hasConstantValue() const {
    // Exploit the fact that phi nodes always have at least one entry.
    Value *ConstantValue = getIncomingValue(0);
    for (unsigned i = 1, e = getNumIncomingValues(); i != e; ++i)
      if (getIncomingValue(i) != ConstantValue && getIncomingValue(i) != this) {
        if (ConstantValue != this)
          return nullptr; // Incoming values not all the same.
         // The case where the first value is this PHI.
        ConstantValue = getIncomingValue(i);
      }
    if (ConstantValue == this)
      return UndefValue::get(getType());
    return ConstantValue;
  }
  
  //===----------------------------------------------------------------------===//
  //                       LandingPadInst Implementation
  //===----------------------------------------------------------------------===//
  
  LandingPadInst::LandingPadInst(Type *RetTy, unsigned NumReservedValues,
                                 const Twine &NameStr, Instruction *InsertBefore)
      : Instruction(RetTy, Instruction::LandingPad, nullptr, 0, InsertBefore) {
    init(NumReservedValues, NameStr);
  }
  
  LandingPadInst::LandingPadInst(Type *RetTy, unsigned NumReservedValues,
                                 const Twine &NameStr, BasicBlock *InsertAtEnd)
      : Instruction(RetTy, Instruction::LandingPad, nullptr, 0, InsertAtEnd) {
    init(NumReservedValues, NameStr);
  }
  
  LandingPadInst::LandingPadInst(const LandingPadInst &LP)
      : Instruction(LP.getType(), Instruction::LandingPad, nullptr,
                    LP.getNumOperands()),
        ReservedSpace(LP.getNumOperands()) {
    allocHungoffUses(LP.getNumOperands());
    Use *OL = getOperandList();
    const Use *InOL = LP.getOperandList();
    for (unsigned I = 0, E = ReservedSpace; I != E; ++I)
      OL[I] = InOL[I];
  
    setCleanup(LP.isCleanup());
  }
  
  LandingPadInst *LandingPadInst::Create(Type *RetTy, unsigned NumReservedClauses,
                                         const Twine &NameStr,
                                         Instruction *InsertBefore) {
    return new LandingPadInst(RetTy, NumReservedClauses, NameStr, InsertBefore);
  }
  
  LandingPadInst *LandingPadInst::Create(Type *RetTy, unsigned NumReservedClauses,
                                         const Twine &NameStr,
                                         BasicBlock *InsertAtEnd) {
    return new LandingPadInst(RetTy, NumReservedClauses, NameStr, InsertAtEnd);
  }
  
  void LandingPadInst::init(unsigned NumReservedValues, const Twine &NameStr) {
    ReservedSpace = NumReservedValues;
    setNumHungOffUseOperands(0);
    allocHungoffUses(ReservedSpace);
    setName(NameStr);
    setCleanup(false);
  }
  
  /// growOperands - grow operands - This grows the operand list in response to a
  /// push_back style of operation. This grows the number of ops by 2 times.
  void LandingPadInst::growOperands(unsigned Size) {
    unsigned e = getNumOperands();
    if (ReservedSpace >= e + Size) return;
    ReservedSpace = (std::max(e, 1U) + Size / 2) * 2;
    growHungoffUses(ReservedSpace);
  }
  
  void LandingPadInst::addClause(Constant *Val) {
    unsigned OpNo = getNumOperands();
    growOperands(1);
    assert(OpNo < ReservedSpace && "Growing didn't work!");
    setNumHungOffUseOperands(getNumOperands() + 1);
    getOperandList()[OpNo] = Val;
  }
  
  //===----------------------------------------------------------------------===//
  //                        CallInst Implementation
  //===----------------------------------------------------------------------===//
  
  CallInst::~CallInst() {
  }
  
  void CallInst::init(FunctionType *FTy, Value *Func, ArrayRef<Value *> Args,
                      const Twine &NameStr) {
    this->FTy = FTy;
    assert(getNumOperands() == Args.size() + 1 && "NumOperands not set up?");
    Op<-1>() = Func;
  
  #ifndef NDEBUG
    assert((Args.size() == FTy->getNumParams() ||
            (FTy->isVarArg() && Args.size() > FTy->getNumParams())) &&
           "Calling a function with bad signature!");
  
    for (unsigned i = 0; i != Args.size(); ++i)
      assert((i >= FTy->getNumParams() || 
              FTy->getParamType(i) == Args[i]->getType()) &&
             "Calling a function with a bad signature!");
  #endif
  
    std::copy(Args.begin(), Args.end(), op_begin());
    setName(NameStr);
  }
  
  void CallInst::init(Value *Func, const Twine &NameStr) {
    FTy =
        cast<FunctionType>(cast<PointerType>(Func->getType())->getElementType());
    assert(getNumOperands() == 1 && "NumOperands not set up?");
    Op<-1>() = Func;
  
    assert(FTy->getNumParams() == 0 && "Calling a function with bad signature");
  
    setName(NameStr);
  }
  
  CallInst::CallInst(Value *Func, const Twine &Name,
                     Instruction *InsertBefore)
    : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                     ->getElementType())->getReturnType(),
                  Instruction::Call,
                  OperandTraits<CallInst>::op_end(this) - 1,
                  1, InsertBefore) {
    init(Func, Name);
  }
  
  CallInst::CallInst(Value *Func, const Twine &Name,
                     BasicBlock *InsertAtEnd)
    : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                     ->getElementType())->getReturnType(),
                  Instruction::Call,
                  OperandTraits<CallInst>::op_end(this) - 1,
                  1, InsertAtEnd) {
    init(Func, Name);
  }
  
  CallInst::CallInst(const CallInst &CI)
      : Instruction(CI.getType(), Instruction::Call,
                    OperandTraits<CallInst>::op_end(this) - CI.getNumOperands(),
                    CI.getNumOperands()),
        AttributeList(CI.AttributeList), FTy(CI.FTy) {
    setTailCallKind(CI.getTailCallKind());
    setCallingConv(CI.getCallingConv());
      
    std::copy(CI.op_begin(), CI.op_end(), op_begin());
    SubclassOptionalData = CI.SubclassOptionalData;
  }
  
  void CallInst::addAttribute(unsigned i, Attribute::AttrKind attr) {
    AttributeSet PAL = getAttributes();
    PAL = PAL.addAttribute(getContext(), i, attr);
    setAttributes(PAL);
  }
  
  void CallInst::removeAttribute(unsigned i, Attribute attr) {
    AttributeSet PAL = getAttributes();
    AttrBuilder B(attr);
    LLVMContext &Context = getContext();
    PAL = PAL.removeAttributes(Context, i,
                               AttributeSet::get(Context, i, B));
    setAttributes(PAL);
  }
  
  void CallInst::addDereferenceableAttr(unsigned i, uint64_t Bytes) {
    AttributeSet PAL = getAttributes();
    PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
    setAttributes(PAL);
  }
  
  void CallInst::addDereferenceableOrNullAttr(unsigned i, uint64_t Bytes) {
    AttributeSet PAL = getAttributes();
    PAL = PAL.addDereferenceableOrNullAttr(getContext(), i, Bytes);
    setAttributes(PAL);
  }
  
  bool CallInst::hasFnAttrImpl(Attribute::AttrKind A) const {
    if (AttributeList.hasAttribute(AttributeSet::FunctionIndex, A))
      return true;
    if (const Function *F = getCalledFunction())
      return F->getAttributes().hasAttribute(AttributeSet::FunctionIndex, A);
    return false;
  }
  
  bool CallInst::paramHasAttr(unsigned i, Attribute::AttrKind A) const {
    if (AttributeList.hasAttribute(i, A))
      return true;
    if (const Function *F = getCalledFunction())
      return F->getAttributes().hasAttribute(i, A);
    return false;
  }
  
  /// IsConstantOne - Return true only if val is constant int 1
  static bool IsConstantOne(Value *val) {
    assert(val && "IsConstantOne does not work with nullptr val");
    const ConstantInt *CVal = dyn_cast<ConstantInt>(val);
    return CVal && CVal->isOne();
  }
  
  static Instruction *createMalloc(Instruction *InsertBefore,
                                   BasicBlock *InsertAtEnd, Type *IntPtrTy,
                                   Type *AllocTy, Value *AllocSize, 
                                   Value *ArraySize, Function *MallocF,
                                   const Twine &Name) {
    assert(((!InsertBefore && InsertAtEnd) || (InsertBefore && !InsertAtEnd)) &&
           "createMalloc needs either InsertBefore or InsertAtEnd");
  
    // malloc(type) becomes: 
    //       bitcast (i8* malloc(typeSize)) to type*
    // malloc(type, arraySize) becomes:
    //       bitcast (i8 *malloc(typeSize*arraySize)) to type*
    if (!ArraySize)
      ArraySize = ConstantInt::get(IntPtrTy, 1);
    else if (ArraySize->getType() != IntPtrTy) {
      if (InsertBefore)
        ArraySize = CastInst::CreateIntegerCast(ArraySize, IntPtrTy, false,
                                                "", InsertBefore);
      else
        ArraySize = CastInst::CreateIntegerCast(ArraySize, IntPtrTy, false,
                                                "", InsertAtEnd);
    }
  
    if (!IsConstantOne(ArraySize)) {
      if (IsConstantOne(AllocSize)) {
        AllocSize = ArraySize;         // Operand * 1 = Operand
      } else if (Constant *CO = dyn_cast<Constant>(ArraySize)) {
        Constant *Scale = ConstantExpr::getIntegerCast(CO, IntPtrTy,
                                                       false /*ZExt*/);
        // Malloc arg is constant product of type size and array size
        AllocSize = ConstantExpr::getMul(Scale, cast<Constant>(AllocSize));
      } else {
        // Multiply type size by the array size...
        if (InsertBefore)
          AllocSize = BinaryOperator::CreateMul(ArraySize, AllocSize,
                                                "mallocsize", InsertBefore);
        else
          AllocSize = BinaryOperator::CreateMul(ArraySize, AllocSize,
                                                "mallocsize", InsertAtEnd);
      }
    }
  
    assert(AllocSize->getType() == IntPtrTy && "malloc arg is wrong size");
    // Create the call to Malloc.
    BasicBlock* BB = InsertBefore ? InsertBefore->getParent() : InsertAtEnd;
    Module* M = BB->getParent()->getParent();
    Type *BPTy = Type::getInt8PtrTy(BB->getContext());
    Value *MallocFunc = MallocF;
    if (!MallocFunc)
      // prototype malloc as "void *malloc(size_t)"
      MallocFunc = M->getOrInsertFunction("malloc", BPTy, IntPtrTy, nullptr);
    PointerType *AllocPtrType = PointerType::getUnqual(AllocTy);
    CallInst *MCall = nullptr;
    Instruction *Result = nullptr;
    if (InsertBefore) {
      MCall = CallInst::Create(MallocFunc, AllocSize, "malloccall", InsertBefore);
      Result = MCall;
      if (Result->getType() != AllocPtrType)
        // Create a cast instruction to convert to the right type...
        Result = new BitCastInst(MCall, AllocPtrType, Name, InsertBefore);
    } else {
      MCall = CallInst::Create(MallocFunc, AllocSize, "malloccall");
      Result = MCall;
      if (Result->getType() != AllocPtrType) {
        InsertAtEnd->getInstList().push_back(MCall);
        // Create a cast instruction to convert to the right type...
        Result = new BitCastInst(MCall, AllocPtrType, Name);
      }
    }
    MCall->setTailCall();
    if (Function *F = dyn_cast<Function>(MallocFunc)) {
      MCall->setCallingConv(F->getCallingConv());
      if (!F->doesNotAlias(0)) F->setDoesNotAlias(0);
    }
    assert(!MCall->getType()->isVoidTy() && "Malloc has void return type");
  
    return Result;
  }
  
  /// CreateMalloc - Generate the IR for a call to malloc:
  /// 1. Compute the malloc call's argument as the specified type's size,
  ///    possibly multiplied by the array size if the array size is not
  ///    constant 1.
  /// 2. Call malloc with that argument.
  /// 3. Bitcast the result of the malloc call to the specified type.
  Instruction *CallInst::CreateMalloc(Instruction *InsertBefore,
                                      Type *IntPtrTy, Type *AllocTy,
                                      Value *AllocSize, Value *ArraySize,
                                      Function * MallocF,
                                      const Twine &Name) {
    return createMalloc(InsertBefore, nullptr, IntPtrTy, AllocTy, AllocSize,
                        ArraySize, MallocF, Name);
  }
  
  /// CreateMalloc - Generate the IR for a call to malloc:
  /// 1. Compute the malloc call's argument as the specified type's size,
  ///    possibly multiplied by the array size if the array size is not
  ///    constant 1.
  /// 2. Call malloc with that argument.
  /// 3. Bitcast the result of the malloc call to the specified type.
  /// Note: This function does not add the bitcast to the basic block, that is the
  /// responsibility of the caller.
  Instruction *CallInst::CreateMalloc(BasicBlock *InsertAtEnd,
                                      Type *IntPtrTy, Type *AllocTy,
                                      Value *AllocSize, Value *ArraySize, 
                                      Function *MallocF, const Twine &Name) {
    return createMalloc(nullptr, InsertAtEnd, IntPtrTy, AllocTy, AllocSize,
                        ArraySize, MallocF, Name);
  }
  
  static Instruction* createFree(Value* Source, Instruction *InsertBefore,
                                 BasicBlock *InsertAtEnd) {
    assert(((!InsertBefore && InsertAtEnd) || (InsertBefore && !InsertAtEnd)) &&
           "createFree needs either InsertBefore or InsertAtEnd");
    assert(Source->getType()->isPointerTy() &&
           "Can not free something of nonpointer type!");
  
    BasicBlock* BB = InsertBefore ? InsertBefore->getParent() : InsertAtEnd;
    Module* M = BB->getParent()->getParent();
  
    Type *VoidTy = Type::getVoidTy(M->getContext());
    Type *IntPtrTy = Type::getInt8PtrTy(M->getContext());
    // prototype free as "void free(void*)"
    Value *FreeFunc = M->getOrInsertFunction("free", VoidTy, IntPtrTy, nullptr);
    CallInst* Result = nullptr;
    Value *PtrCast = Source;
    if (InsertBefore) {
      if (Source->getType() != IntPtrTy)
        PtrCast = new BitCastInst(Source, IntPtrTy, "", InsertBefore);
      Result = CallInst::Create(FreeFunc, PtrCast, "", InsertBefore);
    } else {
      if (Source->getType() != IntPtrTy)
        PtrCast = new BitCastInst(Source, IntPtrTy, "", InsertAtEnd);
      Result = CallInst::Create(FreeFunc, PtrCast, "");
    }
    Result->setTailCall();
    if (Function *F = dyn_cast<Function>(FreeFunc))
      Result->setCallingConv(F->getCallingConv());
  
    return Result;
  }
  
  /// CreateFree - Generate the IR for a call to the builtin free function.
  Instruction * CallInst::CreateFree(Value* Source, Instruction *InsertBefore) {
    return createFree(Source, InsertBefore, nullptr);
  }
  
  /// CreateFree - Generate the IR for a call to the builtin free function.
  /// Note: This function does not add the call to the basic block, that is the
  /// responsibility of the caller.
  Instruction* CallInst::CreateFree(Value* Source, BasicBlock *InsertAtEnd) {
    Instruction* FreeCall = createFree(Source, nullptr, InsertAtEnd);
    assert(FreeCall && "CreateFree did not create a CallInst");
    return FreeCall;
  }
  
  //===----------------------------------------------------------------------===//
  //                        InvokeInst Implementation
  //===----------------------------------------------------------------------===//
  
  void InvokeInst::init(FunctionType *FTy, Value *Fn, BasicBlock *IfNormal,
                        BasicBlock *IfException, ArrayRef<Value *> Args,
                        const Twine &NameStr) {
    this->FTy = FTy;
  
    assert(getNumOperands() == 3 + Args.size() && "NumOperands not set up?");
    Op<-3>() = Fn;
    Op<-2>() = IfNormal;
    Op<-1>() = IfException;
  
  #ifndef NDEBUG
    assert(((Args.size() == FTy->getNumParams()) ||
            (FTy->isVarArg() && Args.size() > FTy->getNumParams())) &&
           "Invoking a function with bad signature");
  
    for (unsigned i = 0, e = Args.size(); i != e; i++)
      assert((i >= FTy->getNumParams() || 
              FTy->getParamType(i) == Args[i]->getType()) &&
             "Invoking a function with a bad signature!");
  #endif
  
    std::copy(Args.begin(), Args.end(), op_begin());
    setName(NameStr);
  }
  
  InvokeInst::InvokeInst(const InvokeInst &II)
      : TerminatorInst(II.getType(), Instruction::Invoke,
                       OperandTraits<InvokeInst>::op_end(this) -
                           II.getNumOperands(),
                       II.getNumOperands()),
        AttributeList(II.AttributeList), FTy(II.FTy) {
    setCallingConv(II.getCallingConv());
    std::copy(II.op_begin(), II.op_end(), op_begin());
    SubclassOptionalData = II.SubclassOptionalData;
  }
  
  BasicBlock *InvokeInst::getSuccessorV(unsigned idx) const {
    return getSuccessor(idx);
  }
  unsigned InvokeInst::getNumSuccessorsV() const {
    return getNumSuccessors();
  }
  void InvokeInst::setSuccessorV(unsigned idx, BasicBlock *B) {
    return setSuccessor(idx, B);
  }
  
  bool InvokeInst::hasFnAttrImpl(Attribute::AttrKind A) const {
    if (AttributeList.hasAttribute(AttributeSet::FunctionIndex, A))
      return true;
    if (const Function *F = getCalledFunction())
      return F->getAttributes().hasAttribute(AttributeSet::FunctionIndex, A);
    return false;
  }
  
  bool InvokeInst::paramHasAttr(unsigned i, Attribute::AttrKind A) const {
    if (AttributeList.hasAttribute(i, A))
      return true;
    if (const Function *F = getCalledFunction())
      return F->getAttributes().hasAttribute(i, A);
    return false;
  }
  
  void InvokeInst::addAttribute(unsigned i, Attribute::AttrKind attr) {
    AttributeSet PAL = getAttributes();
    PAL = PAL.addAttribute(getContext(), i, attr);
    setAttributes(PAL);
  }
  
  void InvokeInst::removeAttribute(unsigned i, Attribute attr) {
    AttributeSet PAL = getAttributes();
    AttrBuilder B(attr);
    PAL = PAL.removeAttributes(getContext(), i,
                               AttributeSet::get(getContext(), i, B));
    setAttributes(PAL);
  }
  
  void InvokeInst::addDereferenceableAttr(unsigned i, uint64_t Bytes) {
    AttributeSet PAL = getAttributes();
    PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
    setAttributes(PAL);
  }
  
  void InvokeInst::addDereferenceableOrNullAttr(unsigned i, uint64_t Bytes) {
    AttributeSet PAL = getAttributes();
    PAL = PAL.addDereferenceableOrNullAttr(getContext(), i, Bytes);
    setAttributes(PAL);
  }
  
  LandingPadInst *InvokeInst::getLandingPadInst() const {
    return cast<LandingPadInst>(getUnwindDest()->getFirstNonPHI());
  }
  
  //===----------------------------------------------------------------------===//
  //                        ReturnInst Implementation
  //===----------------------------------------------------------------------===//
  
  ReturnInst::ReturnInst(const ReturnInst &RI)
    : TerminatorInst(Type::getVoidTy(RI.getContext()), Instruction::Ret,
                     OperandTraits<ReturnInst>::op_end(this) -
                       RI.getNumOperands(),
                     RI.getNumOperands()) {
    if (RI.getNumOperands())
      Op<0>() = RI.Op<0>();
    SubclassOptionalData = RI.SubclassOptionalData;
  }
  
  ReturnInst::ReturnInst(LLVMContext &C, Value *retVal, Instruction *InsertBefore)
    : TerminatorInst(Type::getVoidTy(C), Instruction::Ret,
                     OperandTraits<ReturnInst>::op_end(this) - !!retVal, !!retVal,
                     InsertBefore) {
    if (retVal)
      Op<0>() = retVal;
  }
  ReturnInst::ReturnInst(LLVMContext &C, Value *retVal, BasicBlock *InsertAtEnd)
    : TerminatorInst(Type::getVoidTy(C), Instruction::Ret,
                     OperandTraits<ReturnInst>::op_end(this) - !!retVal, !!retVal,
                     InsertAtEnd) {
    if (retVal)
      Op<0>() = retVal;
  }
  ReturnInst::ReturnInst(LLVMContext &Context, BasicBlock *InsertAtEnd)
    : TerminatorInst(Type::getVoidTy(Context), Instruction::Ret,
                     OperandTraits<ReturnInst>::op_end(this), 0, InsertAtEnd) {
  }
  
  unsigned ReturnInst::getNumSuccessorsV() const {
    return getNumSuccessors();
  }
  
  /// Out-of-line ReturnInst method, put here so the C++ compiler can choose to
  /// emit the vtable for the class in this translation unit.
  void ReturnInst::setSuccessorV(unsigned idx, BasicBlock *NewSucc) {
    llvm_unreachable("ReturnInst has no successors!");
  }
  
  BasicBlock *ReturnInst::getSuccessorV(unsigned idx) const {
    llvm_unreachable("ReturnInst has no successors!");
  }
  
  ReturnInst::~ReturnInst() {
  }
  
  //===----------------------------------------------------------------------===//
  //                        ResumeInst Implementation
  //===----------------------------------------------------------------------===//
  
  ResumeInst::ResumeInst(const ResumeInst &RI)
    : TerminatorInst(Type::getVoidTy(RI.getContext()), Instruction::Resume,
                     OperandTraits<ResumeInst>::op_begin(this), 1) {
    Op<0>() = RI.Op<0>();
  }
  
  ResumeInst::ResumeInst(Value *Exn, Instruction *InsertBefore)
    : TerminatorInst(Type::getVoidTy(Exn->getContext()), Instruction::Resume,
                     OperandTraits<ResumeInst>::op_begin(this), 1, InsertBefore) {
    Op<0>() = Exn;
  }
  
  ResumeInst::ResumeInst(Value *Exn, BasicBlock *InsertAtEnd)
    : TerminatorInst(Type::getVoidTy(Exn->getContext()), Instruction::Resume,
                     OperandTraits<ResumeInst>::op_begin(this), 1, InsertAtEnd) {
    Op<0>() = Exn;
  }
  
  unsigned ResumeInst::getNumSuccessorsV() const {
    return getNumSuccessors();
  }
  
  void ResumeInst::setSuccessorV(unsigned idx, BasicBlock *NewSucc) {
    llvm_unreachable("ResumeInst has no successors!");
  }
  
  BasicBlock *ResumeInst::getSuccessorV(unsigned idx) const {
    llvm_unreachable("ResumeInst has no successors!");
  }
  
  //===----------------------------------------------------------------------===//
  //                      UnreachableInst Implementation
  //===----------------------------------------------------------------------===//
  
  UnreachableInst::UnreachableInst(LLVMContext &Context, 
                                   Instruction *InsertBefore)
    : TerminatorInst(Type::getVoidTy(Context), Instruction::Unreachable,
                     nullptr, 0, InsertBefore) {
  }
  UnreachableInst::UnreachableInst(LLVMContext &Context, BasicBlock *InsertAtEnd)
    : TerminatorInst(Type::getVoidTy(Context), Instruction::Unreachable,
                     nullptr, 0, InsertAtEnd) {
  }
  
  unsigned UnreachableInst::getNumSuccessorsV() const {
    return getNumSuccessors();
  }
  
  void UnreachableInst::setSuccessorV(unsigned idx, BasicBlock *NewSucc) {
    llvm_unreachable("UnreachableInst has no successors!");
  }
  
  BasicBlock *UnreachableInst::getSuccessorV(unsigned idx) const {
    llvm_unreachable("UnreachableInst has no successors!");
  }
  
  //===----------------------------------------------------------------------===//
  //                        BranchInst Implementation
  //===----------------------------------------------------------------------===//
  
  void BranchInst::AssertOK() {
    if (isConditional())
      assert(getCondition()->getType()->isIntegerTy(1) &&
             "May only branch on boolean predicates!");
  }
  
  BranchInst::BranchInst(BasicBlock *IfTrue, Instruction *InsertBefore)
    : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                     OperandTraits<BranchInst>::op_end(this) - 1,
                     1, InsertBefore) {
    assert(IfTrue && "Branch destination may not be null!");
    Op<-1>() = IfTrue;
  }
  BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *IfFalse, Value *Cond,
                         Instruction *InsertBefore)
    : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                     OperandTraits<BranchInst>::op_end(this) - 3,
                     3, InsertBefore) {
    Op<-1>() = IfTrue;
    Op<-2>() = IfFalse;
    Op<-3>() = Cond;
  #ifndef NDEBUG
    AssertOK();
  #endif
  }
  
  BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *InsertAtEnd)
    : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                     OperandTraits<BranchInst>::op_end(this) - 1,
                     1, InsertAtEnd) {
    assert(IfTrue && "Branch destination may not be null!");
    Op<-1>() = IfTrue;
  }
  
  BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *IfFalse, Value *Cond,
             BasicBlock *InsertAtEnd)
    : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                     OperandTraits<BranchInst>::op_end(this) - 3,
                     3, InsertAtEnd) {
    Op<-1>() = IfTrue;
    Op<-2>() = IfFalse;
    Op<-3>() = Cond;
  #ifndef NDEBUG
    AssertOK();
  #endif
  }
  
  
  BranchInst::BranchInst(const BranchInst &BI) :
    TerminatorInst(Type::getVoidTy(BI.getContext()), Instruction::Br,
                   OperandTraits<BranchInst>::op_end(this) - BI.getNumOperands(),
                   BI.getNumOperands()) {
    Op<-1>() = BI.Op<-1>();
    if (BI.getNumOperands() != 1) {
      assert(BI.getNumOperands() == 3 && "BR can have 1 or 3 operands!");
      Op<-3>() = BI.Op<-3>();
      Op<-2>() = BI.Op<-2>();
    }
    SubclassOptionalData = BI.SubclassOptionalData;
  }
  
  void BranchInst::swapSuccessors() {
    assert(isConditional() &&
           "Cannot swap successors of an unconditional branch");
    Op<-1>().swap(Op<-2>());
  
    // Update profile metadata if present and it matches our structural
    // expectations.
    MDNode *ProfileData = getMetadata(LLVMContext::MD_prof);
    if (!ProfileData || ProfileData->getNumOperands() != 3)
      return;
  
    // The first operand is the name. Fetch them backwards and build a new one.
    Metadata *Ops[] = {ProfileData->getOperand(0), ProfileData->getOperand(2),
                       ProfileData->getOperand(1)};
    setMetadata(LLVMContext::MD_prof,
                MDNode::get(ProfileData->getContext(), Ops));
  }
  
  BasicBlock *BranchInst::getSuccessorV(unsigned idx) const {
    return getSuccessor(idx);
  }
  unsigned BranchInst::getNumSuccessorsV() const {
    return getNumSuccessors();
  }
  void BranchInst::setSuccessorV(unsigned idx, BasicBlock *B) {
    setSuccessor(idx, B);
  }
  
  
  //===----------------------------------------------------------------------===//
  //                        AllocaInst Implementation
  //===----------------------------------------------------------------------===//
  
  static Value *getAISize(LLVMContext &Context, Value *Amt) {
    if (!Amt)
      Amt = ConstantInt::get(Type::getInt32Ty(Context), 1);
    else {
      assert(!isa<BasicBlock>(Amt) &&
             "Passed basic block into allocation size parameter! Use other ctor");
      assert(Amt->getType()->isIntegerTy() &&
             "Allocation array size is not an integer!");
    }
    return Amt;
  }
  
  AllocaInst::AllocaInst(Type *Ty, const Twine &Name, Instruction *InsertBefore)
      : AllocaInst(Ty, /*ArraySize=*/nullptr, Name, InsertBefore) {}
  
  AllocaInst::AllocaInst(Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd)
      : AllocaInst(Ty, /*ArraySize=*/nullptr, Name, InsertAtEnd) {}
  
  AllocaInst::AllocaInst(Type *Ty, Value *ArraySize, const Twine &Name,
                         Instruction *InsertBefore)
      : AllocaInst(Ty, ArraySize, /*Align=*/0, Name, InsertBefore) {}
  
  AllocaInst::AllocaInst(Type *Ty, Value *ArraySize, const Twine &Name,
                         BasicBlock *InsertAtEnd)
      : AllocaInst(Ty, ArraySize, /*Align=*/0, Name, InsertAtEnd) {}
  
  AllocaInst::AllocaInst(Type *Ty, Value *ArraySize, unsigned Align,
                         const Twine &Name, Instruction *InsertBefore)
      : UnaryInstruction(PointerType::getUnqual(Ty), Alloca,
                         getAISize(Ty->getContext(), ArraySize), InsertBefore),
        AllocatedType(Ty) {
    setAlignment(Align);
    assert(!Ty->isVoidTy() && "Cannot allocate void!");
    setName(Name);
  }
  
  AllocaInst::AllocaInst(Type *Ty, Value *ArraySize, unsigned Align,
                         const Twine &Name, BasicBlock *InsertAtEnd)
      : UnaryInstruction(PointerType::getUnqual(Ty), Alloca,
                         getAISize(Ty->getContext(), ArraySize), InsertAtEnd),
        AllocatedType(Ty) {
    setAlignment(Align);
    assert(!Ty->isVoidTy() && "Cannot allocate void!");
    setName(Name);
  }
  
  // Out of line virtual method, so the vtable, etc has a home.
  AllocaInst::~AllocaInst() {
  }
  
  void AllocaInst::setAlignment(unsigned Align) {
    assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
    assert(Align <= MaximumAlignment &&
           "Alignment is greater than MaximumAlignment!");
    setInstructionSubclassData((getSubclassDataFromInstruction() & ~31) |
                               (Log2_32(Align) + 1));
    assert(getAlignment() == Align && "Alignment representation error!");
  }
  
  bool AllocaInst::isArrayAllocation() const {
    if (ConstantInt *CI = dyn_cast<ConstantInt>(getOperand(0)))
      return !CI->isOne();
    return true;
  }
  
  /// isStaticAlloca - Return true if this alloca is in the entry block of the
  /// function and is a constant size.  If so, the code generator will fold it
  /// into the prolog/epilog code, so it is basically free.
  bool AllocaInst::isStaticAlloca() const {
    // Must be constant size.
    if (!isa<ConstantInt>(getArraySize())) return false;
    
    // Must be in the entry block.
    const BasicBlock *Parent = getParent();
    return Parent == &Parent->getParent()->front() && !isUsedWithInAlloca();
  }
  
  //===----------------------------------------------------------------------===//
  //                           LoadInst Implementation
  //===----------------------------------------------------------------------===//
  
  void LoadInst::AssertOK() {
    assert(getOperand(0)->getType()->isPointerTy() &&
           "Ptr must have pointer type.");
    assert(!(isAtomic() && getAlignment() == 0) &&
           "Alignment required for atomic load");
  }
  
  LoadInst::LoadInst(Value *Ptr, const Twine &Name, Instruction *InsertBef)
      : LoadInst(Ptr, Name, /*isVolatile=*/false, InsertBef) {}
  
  LoadInst::LoadInst(Value *Ptr, const Twine &Name, BasicBlock *InsertAE)
      : LoadInst(Ptr, Name, /*isVolatile=*/false, InsertAE) {}
  
  LoadInst::LoadInst(Type *Ty, Value *Ptr, const Twine &Name, bool isVolatile,
                     Instruction *InsertBef)
      : LoadInst(Ty, Ptr, Name, isVolatile, /*Align=*/0, InsertBef) {}
  
  LoadInst::LoadInst(Value *Ptr, const Twine &Name, bool isVolatile,
                     BasicBlock *InsertAE)
      : LoadInst(Ptr, Name, isVolatile, /*Align=*/0, InsertAE) {}
  
  LoadInst::LoadInst(Type *Ty, Value *Ptr, const Twine &Name, bool isVolatile,
                     unsigned Align, Instruction *InsertBef)
      : LoadInst(Ty, Ptr, Name, isVolatile, Align, NotAtomic, CrossThread,
                 InsertBef) {}
  
  LoadInst::LoadInst(Value *Ptr, const Twine &Name, bool isVolatile,
                     unsigned Align, BasicBlock *InsertAE)
      : LoadInst(Ptr, Name, isVolatile, Align, NotAtomic, CrossThread, InsertAE) {
  }
  
  LoadInst::LoadInst(Type *Ty, Value *Ptr, const Twine &Name, bool isVolatile,
                     unsigned Align, AtomicOrdering Order,
                     SynchronizationScope SynchScope, Instruction *InsertBef)
      : UnaryInstruction(Ty, Load, Ptr, InsertBef) {
    assert(Ty == cast<PointerType>(Ptr->getType())->getElementType());
    setVolatile(isVolatile);
    setAlignment(Align);
    setAtomic(Order, SynchScope);
    AssertOK();
    setName(Name);
  }
  
  LoadInst::LoadInst(Value *Ptr, const Twine &Name, bool isVolatile, 
                     unsigned Align, AtomicOrdering Order,
                     SynchronizationScope SynchScope,
                     BasicBlock *InsertAE)
    : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                       Load, Ptr, InsertAE) {
    setVolatile(isVolatile);
    setAlignment(Align);
    setAtomic(Order, SynchScope);
    AssertOK();
    setName(Name);
  }
  
  LoadInst::LoadInst(Value *Ptr, const char *Name, Instruction *InsertBef)
    : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                       Load, Ptr, InsertBef) {
    setVolatile(false);
    setAlignment(0);
    setAtomic(NotAtomic);
    AssertOK();
    if (Name && Name[0]) setName(Name);
  }
  
  LoadInst::LoadInst(Value *Ptr, const char *Name, BasicBlock *InsertAE)
    : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                       Load, Ptr, InsertAE) {
    setVolatile(false);
    setAlignment(0);
    setAtomic(NotAtomic);
    AssertOK();
    if (Name && Name[0]) setName(Name);
  }
  
  LoadInst::LoadInst(Type *Ty, Value *Ptr, const char *Name, bool isVolatile,
                     Instruction *InsertBef)
      : UnaryInstruction(Ty, Load, Ptr, InsertBef) {
    assert(Ty == cast<PointerType>(Ptr->getType())->getElementType());
    setVolatile(isVolatile);
    setAlignment(0);
    setAtomic(NotAtomic);
    AssertOK();
    if (Name && Name[0]) setName(Name);
  }
  
  LoadInst::LoadInst(Value *Ptr, const char *Name, bool isVolatile,
                     BasicBlock *InsertAE)
    : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                       Load, Ptr, InsertAE) {
    setVolatile(isVolatile);
    setAlignment(0);
    setAtomic(NotAtomic);
    AssertOK();
    if (Name && Name[0]) setName(Name);
  }
  
  void LoadInst::setAlignment(unsigned Align) {
    assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
    assert(Align <= MaximumAlignment &&
           "Alignment is greater than MaximumAlignment!");
    setInstructionSubclassData((getSubclassDataFromInstruction() & ~(31 << 1)) |
                               ((Log2_32(Align)+1)<<1));
    assert(getAlignment() == Align && "Alignment representation error!");
  }
  
  //===----------------------------------------------------------------------===//
  //                           StoreInst Implementation
  //===----------------------------------------------------------------------===//
  
  void StoreInst::AssertOK() {
    assert(getOperand(0) && getOperand(1) && "Both operands must be non-null!");
    assert(getOperand(1)->getType()->isPointerTy() &&
           "Ptr must have pointer type!");
    assert(getOperand(0)->getType() ==
                   cast<PointerType>(getOperand(1)->getType())->getElementType()
           && "Ptr must be a pointer to Val type!");
    assert(!(isAtomic() && getAlignment() == 0) &&
           "Alignment required for atomic store");
  }
  
  StoreInst::StoreInst(Value *val, Value *addr, Instruction *InsertBefore)
      : StoreInst(val, addr, /*isVolatile=*/false, InsertBefore) {}
  
  StoreInst::StoreInst(Value *val, Value *addr, BasicBlock *InsertAtEnd)
      : StoreInst(val, addr, /*isVolatile=*/false, InsertAtEnd) {}
  
  StoreInst::StoreInst(Value *val, Value *addr, bool isVolatile,
                       Instruction *InsertBefore)
      : StoreInst(val, addr, isVolatile, /*Align=*/0, InsertBefore) {}
  
  StoreInst::StoreInst(Value *val, Value *addr, bool isVolatile,
                       BasicBlock *InsertAtEnd)
      : StoreInst(val, addr, isVolatile, /*Align=*/0, InsertAtEnd) {}
  
  StoreInst::StoreInst(Value *val, Value *addr, bool isVolatile, unsigned Align,
                       Instruction *InsertBefore)
      : StoreInst(val, addr, isVolatile, Align, NotAtomic, CrossThread,
                  InsertBefore) {}
  
  StoreInst::StoreInst(Value *val, Value *addr, bool isVolatile, unsigned Align,
                       BasicBlock *InsertAtEnd)
      : StoreInst(val, addr, isVolatile, Align, NotAtomic, CrossThread,
                  InsertAtEnd) {}
  
  StoreInst::StoreInst(Value *val, Value *addr, bool isVolatile,
                       unsigned Align, AtomicOrdering Order,
                       SynchronizationScope SynchScope,
                       Instruction *InsertBefore)
    : Instruction(Type::getVoidTy(val->getContext()), Store,
                  OperandTraits<StoreInst>::op_begin(this),
                  OperandTraits<StoreInst>::operands(this),
                  InsertBefore) {
    Op<0>() = val;
    Op<1>() = addr;
    setVolatile(isVolatile);
    setAlignment(Align);
    setAtomic(Order, SynchScope);
    AssertOK();
  }
  
  StoreInst::StoreInst(Value *val, Value *addr, bool isVolatile,
                       unsigned Align, AtomicOrdering Order,
                       SynchronizationScope SynchScope,
                       BasicBlock *InsertAtEnd)
    : Instruction(Type::getVoidTy(val->getContext()), Store,
                  OperandTraits<StoreInst>::op_begin(this),
                  OperandTraits<StoreInst>::operands(this),
                  InsertAtEnd) {
    Op<0>() = val;
    Op<1>() = addr;
    setVolatile(isVolatile);
    setAlignment(Align);
    setAtomic(Order, SynchScope);
    AssertOK();
  }
  
  void StoreInst::setAlignment(unsigned Align) {
    assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
    assert(Align <= MaximumAlignment &&
           "Alignment is greater than MaximumAlignment!");
    setInstructionSubclassData((getSubclassDataFromInstruction() & ~(31 << 1)) |
                               ((Log2_32(Align)+1) << 1));
    assert(getAlignment() == Align && "Alignment representation error!");
  }
  
  //===----------------------------------------------------------------------===//
  //                       AtomicCmpXchgInst Implementation
  //===----------------------------------------------------------------------===//
  
  void AtomicCmpXchgInst::Init(Value *Ptr, Value *Cmp, Value *NewVal,
                               AtomicOrdering SuccessOrdering,
                               AtomicOrdering FailureOrdering,
                               SynchronizationScope SynchScope) {
    Op<0>() = Ptr;
    Op<1>() = Cmp;
    Op<2>() = NewVal;
    setSuccessOrdering(SuccessOrdering);
    setFailureOrdering(FailureOrdering);
    setSynchScope(SynchScope);
  
    assert(getOperand(0) && getOperand(1) && getOperand(2) &&
           "All operands must be non-null!");
    assert(getOperand(0)->getType()->isPointerTy() &&
           "Ptr must have pointer type!");
    assert(getOperand(1)->getType() ==
                   cast<PointerType>(getOperand(0)->getType())->getElementType()
           && "Ptr must be a pointer to Cmp type!");
    assert(getOperand(2)->getType() ==
                   cast<PointerType>(getOperand(0)->getType())->getElementType()
           && "Ptr must be a pointer to NewVal type!");
    assert(SuccessOrdering != NotAtomic &&
           "AtomicCmpXchg instructions must be atomic!");
    assert(FailureOrdering != NotAtomic &&
           "AtomicCmpXchg instructions must be atomic!");
    assert(SuccessOrdering >= FailureOrdering &&
           "AtomicCmpXchg success ordering must be at least as strong as fail");
    assert(FailureOrdering != Release && FailureOrdering != AcquireRelease &&
           "AtomicCmpXchg failure ordering cannot include release semantics");
  }
  
  AtomicCmpXchgInst::AtomicCmpXchgInst(Value *Ptr, Value *Cmp, Value *NewVal,
                                       AtomicOrdering SuccessOrdering,
                                       AtomicOrdering FailureOrdering,
                                       SynchronizationScope SynchScope,
                                       Instruction *InsertBefore)
      : Instruction(
            StructType::get(Cmp->getType(), Type::getInt1Ty(Cmp->getContext()),
                            nullptr),
            AtomicCmpXchg, OperandTraits<AtomicCmpXchgInst>::op_begin(this),
            OperandTraits<AtomicCmpXchgInst>::operands(this), InsertBefore) {
    Init(Ptr, Cmp, NewVal, SuccessOrdering, FailureOrdering, SynchScope);
  }
  
  AtomicCmpXchgInst::AtomicCmpXchgInst(Value *Ptr, Value *Cmp, Value *NewVal,
                                       AtomicOrdering SuccessOrdering,
                                       AtomicOrdering FailureOrdering,
                                       SynchronizationScope SynchScope,
                                       BasicBlock *InsertAtEnd)
      : Instruction(
            StructType::get(Cmp->getType(), Type::getInt1Ty(Cmp->getContext()),
                            nullptr),
            AtomicCmpXchg, OperandTraits<AtomicCmpXchgInst>::op_begin(this),
            OperandTraits<AtomicCmpXchgInst>::operands(this), InsertAtEnd) {
    Init(Ptr, Cmp, NewVal, SuccessOrdering, FailureOrdering, SynchScope);
  }
  
  //===----------------------------------------------------------------------===//
  //                       AtomicRMWInst Implementation
  //===----------------------------------------------------------------------===//
  
  void AtomicRMWInst::Init(BinOp Operation, Value *Ptr, Value *Val,
                           AtomicOrdering Ordering,
                           SynchronizationScope SynchScope) {
    Op<0>() = Ptr;
    Op<1>() = Val;
    setOperation(Operation);
    setOrdering(Ordering);
    setSynchScope(SynchScope);
  
    assert(getOperand(0) && getOperand(1) &&
           "All operands must be non-null!");
    assert(getOperand(0)->getType()->isPointerTy() &&
           "Ptr must have pointer type!");
    assert(getOperand(1)->getType() ==
           cast<PointerType>(getOperand(0)->getType())->getElementType()
           && "Ptr must be a pointer to Val type!");
    assert(Ordering != NotAtomic &&
           "AtomicRMW instructions must be atomic!");
  }
  
  AtomicRMWInst::AtomicRMWInst(BinOp Operation, Value *Ptr, Value *Val,
                               AtomicOrdering Ordering,
                               SynchronizationScope SynchScope,
                               Instruction *InsertBefore)
    : Instruction(Val->getType(), AtomicRMW,
                  OperandTraits<AtomicRMWInst>::op_begin(this),
                  OperandTraits<AtomicRMWInst>::operands(this),
                  InsertBefore) {
    Init(Operation, Ptr, Val, Ordering, SynchScope);
  }
  
  AtomicRMWInst::AtomicRMWInst(BinOp Operation, Value *Ptr, Value *Val,
                               AtomicOrdering Ordering,
                               SynchronizationScope SynchScope,
                               BasicBlock *InsertAtEnd)
    : Instruction(Val->getType(), AtomicRMW,
                  OperandTraits<AtomicRMWInst>::op_begin(this),
                  OperandTraits<AtomicRMWInst>::operands(this),
                  InsertAtEnd) {
    Init(Operation, Ptr, Val, Ordering, SynchScope);
  }
  
  //===----------------------------------------------------------------------===//
  //                       FenceInst Implementation
  //===----------------------------------------------------------------------===//
  
  FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering, 
                       SynchronizationScope SynchScope,
                       Instruction *InsertBefore)
    : Instruction(Type::getVoidTy(C), Fence, nullptr, 0, InsertBefore) {
    setOrdering(Ordering);
    setSynchScope(SynchScope);
  }
  
  FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering, 
                       SynchronizationScope SynchScope,
                       BasicBlock *InsertAtEnd)
    : Instruction(Type::getVoidTy(C), Fence, nullptr, 0, InsertAtEnd) {
    setOrdering(Ordering);
    setSynchScope(SynchScope);
  }
  
  //===----------------------------------------------------------------------===//
  //                       GetElementPtrInst Implementation
  //===----------------------------------------------------------------------===//
  
  void GetElementPtrInst::init(Value *Ptr, ArrayRef<Value *> IdxList,
                               const Twine &Name) {
    assert(getNumOperands() == 1 + IdxList.size() &&
           "NumOperands not initialized?");
    Op<0>() = Ptr;
    std::copy(IdxList.begin(), IdxList.end(), op_begin() + 1);
    setName(Name);
  }
  
  GetElementPtrInst::GetElementPtrInst(const GetElementPtrInst &GEPI)
      : Instruction(GEPI.getType(), GetElementPtr,
                    OperandTraits<GetElementPtrInst>::op_end(this) -
                        GEPI.getNumOperands(),
                    GEPI.getNumOperands()),
        SourceElementType(GEPI.SourceElementType),
        ResultElementType(GEPI.ResultElementType) {
    std::copy(GEPI.op_begin(), GEPI.op_end(), op_begin());
    SubclassOptionalData = GEPI.SubclassOptionalData;
  }
  
  /// getIndexedType - Returns the type of the element that would be accessed with
  /// a gep instruction with the specified parameters.
  ///
  /// The Idxs pointer should point to a continuous piece of memory containing the
  /// indices, either as Value* or uint64_t.
  ///
  /// A null type is returned if the indices are invalid for the specified
  /// pointer type.
  ///
  template <typename IndexTy>
  static Type *getIndexedTypeInternal(Type *Agg, ArrayRef<IndexTy> IdxList) {
    // Handle the special case of the empty set index set, which is always valid.
    if (IdxList.empty())
      return Agg;
  
    // If there is at least one index, the top level type must be sized, otherwise
    // it cannot be 'stepped over'.
    if (!Agg->isSized())
      return nullptr;
  
    unsigned CurIdx = 1;
    for (; CurIdx != IdxList.size(); ++CurIdx) {
      CompositeType *CT = dyn_cast<CompositeType>(Agg);
      if (!CT || CT->isPointerTy()) return nullptr;
      IndexTy Index = IdxList[CurIdx];
      if (!CT->indexValid(Index)) return nullptr;
      Agg = CT->getTypeAtIndex(Index);
    }
    return CurIdx == IdxList.size() ? Agg : nullptr;
  }
  
  Type *GetElementPtrInst::getIndexedType(Type *Ty, ArrayRef<Value *> IdxList) {
    return getIndexedTypeInternal(Ty, IdxList);
  }
  
  Type *GetElementPtrInst::getIndexedType(Type *Ty,
                                          ArrayRef<Constant *> IdxList) {
    return getIndexedTypeInternal(Ty, IdxList);
  }
  
  Type *GetElementPtrInst::getIndexedType(Type *Ty, ArrayRef<uint64_t> IdxList) {
    return getIndexedTypeInternal(Ty, IdxList);
  }
  
  /// hasAllZeroIndices - Return true if all of the indices of this GEP are
  /// zeros.  If so, the result pointer and the first operand have the same
  /// value, just potentially different types.
  bool GetElementPtrInst::hasAllZeroIndices() const {
    for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
      if (ConstantInt *CI = dyn_cast<ConstantInt>(getOperand(i))) {
        if (!CI->isZero()) return false;
      } else {
        return false;
      }
    }
    return true;
  }
  
  /// hasAllConstantIndices - Return true if all of the indices of this GEP are
  /// constant integers.  If so, the result pointer and the first operand have
  /// a constant offset between them.
  bool GetElementPtrInst::hasAllConstantIndices() const {
    for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
      if (!isa<ConstantInt>(getOperand(i)))
        return false;
    }
    return true;
  }
  
  void GetElementPtrInst::setIsInBounds(bool B) {
    cast<GEPOperator>(this)->setIsInBounds(B);
  }
  
  bool GetElementPtrInst::isInBounds() const {
    return cast<GEPOperator>(this)->isInBounds();
  }
  
  bool GetElementPtrInst::accumulateConstantOffset(const DataLayout &DL,
                                                   APInt &Offset) const {
    // Delegate to the generic GEPOperator implementation.
    return cast<GEPOperator>(this)->accumulateConstantOffset(DL, Offset);
  }
  
  //===----------------------------------------------------------------------===//
  //                           ExtractElementInst Implementation
  //===----------------------------------------------------------------------===//
  
  ExtractElementInst::ExtractElementInst(Value *Val, Value *Index,
                                         const Twine &Name,
                                         Instruction *InsertBef)
    : Instruction(cast<VectorType>(Val->getType())->getElementType(),
                  ExtractElement,
                  OperandTraits<ExtractElementInst>::op_begin(this),
                  2, InsertBef) {
    assert(isValidOperands(Val, Index) &&
           "Invalid extractelement instruction operands!");
    Op<0>() = Val;
    Op<1>() = Index;
    setName(Name);
  }
  
  ExtractElementInst::ExtractElementInst(Value *Val, Value *Index,
                                         const Twine &Name,
                                         BasicBlock *InsertAE)
    : Instruction(cast<VectorType>(Val->getType())->getElementType(),
                  ExtractElement,
                  OperandTraits<ExtractElementInst>::op_begin(this),
                  2, InsertAE) {
    assert(isValidOperands(Val, Index) &&
           "Invalid extractelement instruction operands!");
  
    Op<0>() = Val;
    Op<1>() = Index;
    setName(Name);
  }
  
  
  bool ExtractElementInst::isValidOperands(const Value *Val, const Value *Index) {
    if (!Val->getType()->isVectorTy() || !Index->getType()->isIntegerTy())
      return false;
    return true;
  }
  
  
  //===----------------------------------------------------------------------===//
  //                           InsertElementInst Implementation
  //===----------------------------------------------------------------------===//
  
  InsertElementInst::InsertElementInst(Value *Vec, Value *Elt, Value *Index,
                                       const Twine &Name,
                                       Instruction *InsertBef)
    : Instruction(Vec->getType(), InsertElement,
                  OperandTraits<InsertElementInst>::op_begin(this),
                  3, InsertBef) {
    assert(isValidOperands(Vec, Elt, Index) &&
           "Invalid insertelement instruction operands!");
    Op<0>() = Vec;
    Op<1>() = Elt;
    Op<2>() = Index;
    setName(Name);
  }
  
  InsertElementInst::InsertElementInst(Value *Vec, Value *Elt, Value *Index,
                                       const Twine &Name,
                                       BasicBlock *InsertAE)
    : Instruction(Vec->getType(), InsertElement,
                  OperandTraits<InsertElementInst>::op_begin(this),
                  3, InsertAE) {
    assert(isValidOperands(Vec, Elt, Index) &&
           "Invalid insertelement instruction operands!");
  
    Op<0>() = Vec;
    Op<1>() = Elt;
    Op<2>() = Index;
    setName(Name);
  }
  
  bool InsertElementInst::isValidOperands(const Value *Vec, const Value *Elt, 
                                          const Value *Index) {
    if (!Vec->getType()->isVectorTy())
      return false;   // First operand of insertelement must be vector type.
    
    if (Elt->getType() != cast<VectorType>(Vec->getType())->getElementType())
      return false;// Second operand of insertelement must be vector element type.
      
    if (!Index->getType()->isIntegerTy())
      return false;  // Third operand of insertelement must be i32.
    return true;
  }
  
  
  //===----------------------------------------------------------------------===//
  //                      ShuffleVectorInst Implementation
  //===----------------------------------------------------------------------===//
  
  ShuffleVectorInst::ShuffleVectorInst(Value *V1, Value *V2, Value *Mask,
                                       const Twine &Name,
                                       Instruction *InsertBefore)
  : Instruction(VectorType::get(cast<VectorType>(V1->getType())->getElementType(),
                  cast<VectorType>(Mask->getType())->getNumElements()),
                ShuffleVector,
                OperandTraits<ShuffleVectorInst>::op_begin(this),
                OperandTraits<ShuffleVectorInst>::operands(this),
                InsertBefore) {
    assert(isValidOperands(V1, V2, Mask) &&
           "Invalid shuffle vector instruction operands!");
    Op<0>() = V1;
    Op<1>() = V2;
    Op<2>() = Mask;
    setName(Name);
  }
  
  ShuffleVectorInst::ShuffleVectorInst(Value *V1, Value *V2, Value *Mask,
                                       const Twine &Name,
                                       BasicBlock *InsertAtEnd)
  : Instruction(VectorType::get(cast<VectorType>(V1->getType())->getElementType(),
                  cast<VectorType>(Mask->getType())->getNumElements()),
                ShuffleVector,
                OperandTraits<ShuffleVectorInst>::op_begin(this),
                OperandTraits<ShuffleVectorInst>::operands(this),
                InsertAtEnd) {
    assert(isValidOperands(V1, V2, Mask) &&
           "Invalid shuffle vector instruction operands!");
  
    Op<0>() = V1;
    Op<1>() = V2;
    Op<2>() = Mask;
    setName(Name);
  }
  
  bool ShuffleVectorInst::isValidOperands(const Value *V1, const Value *V2,
                                          const Value *Mask) {
    // V1 and V2 must be vectors of the same type.
    if (!V1->getType()->isVectorTy() || V1->getType() != V2->getType())
      return false;
    
    // Mask must be vector of i32.
    VectorType *MaskTy = dyn_cast<VectorType>(Mask->getType());
    if (!MaskTy || !MaskTy->getElementType()->isIntegerTy(32))
      return false;
  
    // Check to see if Mask is valid.
    if (isa<UndefValue>(Mask) || isa<ConstantAggregateZero>(Mask))
      return true;
  
    if (const ConstantVector *MV = dyn_cast<ConstantVector>(Mask)) {
      unsigned V1Size = cast<VectorType>(V1->getType())->getNumElements();
      for (Value *Op : MV->operands()) {
        if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
          if (CI->uge(V1Size*2))
            return false;
        } else if (!isa<UndefValue>(Op)) {
          return false;
        }
      }
      return true;
    }
    
    if (const ConstantDataSequential *CDS =
          dyn_cast<ConstantDataSequential>(Mask)) {
      unsigned V1Size = cast<VectorType>(V1->getType())->getNumElements();
      for (unsigned i = 0, e = MaskTy->getNumElements(); i != e; ++i)
        if (CDS->getElementAsInteger(i) >= V1Size*2)
          return false;
      return true;
    }
    
    // The bitcode reader can create a place holder for a forward reference
    // used as the shuffle mask. When this occurs, the shuffle mask will
    // fall into this case and fail. To avoid this error, do this bit of
    // ugliness to allow such a mask pass.
    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Mask))
      if (CE->getOpcode() == Instruction::UserOp1)
        return true;
  
    return false;
  }
  
  /// getMaskValue - Return the index from the shuffle mask for the specified
  /// output result.  This is either -1 if the element is undef or a number less
  /// than 2*numelements.
  int ShuffleVectorInst::getMaskValue(Constant *Mask, unsigned i) {
    assert(i < Mask->getType()->getVectorNumElements() && "Index out of range");
    if (ConstantDataSequential *CDS =dyn_cast<ConstantDataSequential>(Mask))
      return CDS->getElementAsInteger(i);
    Constant *C = Mask->getAggregateElement(i);
    if (isa<UndefValue>(C))
      return -1;
    return cast<ConstantInt>(C)->getZExtValue();
  }
  
  /// getShuffleMask - Return the full mask for this instruction, where each
  /// element is the element number and undef's are returned as -1.
  void ShuffleVectorInst::getShuffleMask(Constant *Mask,
                                         SmallVectorImpl<int> &Result) {
    unsigned NumElts = Mask->getType()->getVectorNumElements();
    
    if (ConstantDataSequential *CDS=dyn_cast<ConstantDataSequential>(Mask)) {
      for (unsigned i = 0; i != NumElts; ++i)
        Result.push_back(CDS->getElementAsInteger(i));
      return;
    }    
    for (unsigned i = 0; i != NumElts; ++i) {
      Constant *C = Mask->getAggregateElement(i);
      Result.push_back(isa<UndefValue>(C) ? -1 :
                       cast<ConstantInt>(C)->getZExtValue());
    }
  }
  
  
  //===----------------------------------------------------------------------===//
  //                             InsertValueInst Class
  //===----------------------------------------------------------------------===//
  
  void InsertValueInst::init(Value *Agg, Value *Val, ArrayRef<unsigned> Idxs, 
                             const Twine &Name) {
    assert(getNumOperands() == 2 && "NumOperands not initialized?");
  
    // There's no fundamental reason why we require at least one index
    // (other than weirdness with &*IdxBegin being invalid; see
    // getelementptr's init routine for example). But there's no
    // present need to support it.
    assert(Idxs.size() > 0 && "InsertValueInst must have at least one index");
  
    assert(ExtractValueInst::getIndexedType(Agg->getType(), Idxs) ==
           Val->getType() && "Inserted value must match indexed type!");
    Op<0>() = Agg;
    Op<1>() = Val;
  
    Indices.append(Idxs.begin(), Idxs.end());
    setName(Name);
  }
  
  InsertValueInst::InsertValueInst(const InsertValueInst &IVI)
    : Instruction(IVI.getType(), InsertValue,
                  OperandTraits<InsertValueInst>::op_begin(this), 2),
      Indices(IVI.Indices) {
    Op<0>() = IVI.getOperand(0);
    Op<1>() = IVI.getOperand(1);
    SubclassOptionalData = IVI.SubclassOptionalData;
  }
  
  //===----------------------------------------------------------------------===//
  //                             ExtractValueInst Class
  //===----------------------------------------------------------------------===//
  
  void ExtractValueInst::init(ArrayRef<unsigned> Idxs, const Twine &Name) {
    assert(getNumOperands() == 1 && "NumOperands not initialized?");
  
    // There's no fundamental reason why we require at least one index.
    // But there's no present need to support it.
    assert(Idxs.size() > 0 && "ExtractValueInst must have at least one index");
  
    Indices.append(Idxs.begin(), Idxs.end());
    setName(Name);
  }
  
  ExtractValueInst::ExtractValueInst(const ExtractValueInst &EVI)
    : UnaryInstruction(EVI.getType(), ExtractValue, EVI.getOperand(0)),
      Indices(EVI.Indices) {
    SubclassOptionalData = EVI.SubclassOptionalData;
  }
  
  // getIndexedType - Returns the type of the element that would be extracted
  // with an extractvalue instruction with the specified parameters.
  //
  // A null type is returned if the indices are invalid for the specified
  // pointer type.
  //
  Type *ExtractValueInst::getIndexedType(Type *Agg,
                                         ArrayRef<unsigned> Idxs) {
    for (unsigned Index : Idxs) {
      // We can't use CompositeType::indexValid(Index) here.
      // indexValid() always returns true for arrays because getelementptr allows
      // out-of-bounds indices. Since we don't allow those for extractvalue and
      // insertvalue we need to check array indexing manually.
      // Since the only other types we can index into are struct types it's just
      // as easy to check those manually as well.
      if (ArrayType *AT = dyn_cast<ArrayType>(Agg)) {
        if (Index >= AT->getNumElements())
          return nullptr;
      } else if (StructType *ST = dyn_cast<StructType>(Agg)) {
        if (Index >= ST->getNumElements())
          return nullptr;
      } else {
        // Not a valid type to index into.
        return nullptr;
      }
  
      Agg = cast<CompositeType>(Agg)->getTypeAtIndex(Index);
    }
    return const_cast<Type*>(Agg);
  }
  
  //===----------------------------------------------------------------------===//
  //                             BinaryOperator Class
  //===----------------------------------------------------------------------===//
  
  BinaryOperator::BinaryOperator(BinaryOps iType, Value *S1, Value *S2,
                                 Type *Ty, const Twine &Name,
                                 Instruction *InsertBefore)
    : Instruction(Ty, iType,
                  OperandTraits<BinaryOperator>::op_begin(this),
                  OperandTraits<BinaryOperator>::operands(this),
                  InsertBefore) {
    Op<0>() = S1;
    Op<1>() = S2;
    init(iType);
    setName(Name);
  }
  
  BinaryOperator::BinaryOperator(BinaryOps iType, Value *S1, Value *S2, 
                                 Type *Ty, const Twine &Name,
                                 BasicBlock *InsertAtEnd)
    : Instruction(Ty, iType,
                  OperandTraits<BinaryOperator>::op_begin(this),
                  OperandTraits<BinaryOperator>::operands(this),
                  InsertAtEnd) {
    Op<0>() = S1;
    Op<1>() = S2;
    init(iType);
    setName(Name);
  }
  
  
  void BinaryOperator::init(BinaryOps iType) {
    Value *LHS = getOperand(0), *RHS = getOperand(1);
    (void)LHS; (void)RHS; // Silence warnings.
    assert(LHS->getType() == RHS->getType() &&
           "Binary operator operand types must match!");
  #ifndef NDEBUG
    switch (iType) {
    case Add: case Sub:
    case Mul:
      assert(getType() == LHS->getType() &&
             "Arithmetic operation should return same type as operands!");
      assert(getType()->isIntOrIntVectorTy() &&
             "Tried to create an integer operation on a non-integer type!");
      break;
    case FAdd: case FSub:
    case FMul:
      assert(getType() == LHS->getType() &&
             "Arithmetic operation should return same type as operands!");
      assert(getType()->isFPOrFPVectorTy() &&
             "Tried to create a floating-point operation on a "
             "non-floating-point type!");
      break;
    case UDiv: 
    case SDiv: 
      assert(getType() == LHS->getType() &&
             "Arithmetic operation should return same type as operands!");
      assert((getType()->isIntegerTy() || (getType()->isVectorTy() && 
              cast<VectorType>(getType())->getElementType()->isIntegerTy())) &&
             "Incorrect operand type (not integer) for S/UDIV");
      break;
    case FDiv:
      assert(getType() == LHS->getType() &&
             "Arithmetic operation should return same type as operands!");
      assert(getType()->isFPOrFPVectorTy() &&
             "Incorrect operand type (not floating point) for FDIV");
      break;
    case URem: 
    case SRem: 
      assert(getType() == LHS->getType() &&
             "Arithmetic operation should return same type as operands!");
      assert((getType()->isIntegerTy() || (getType()->isVectorTy() && 
              cast<VectorType>(getType())->getElementType()->isIntegerTy())) &&
             "Incorrect operand type (not integer) for S/UREM");
      break;
    case FRem:
      assert(getType() == LHS->getType() &&
             "Arithmetic operation should return same type as operands!");
      assert(getType()->isFPOrFPVectorTy() &&
             "Incorrect operand type (not floating point) for FREM");
      break;
    case Shl:
    case LShr:
    case AShr:
      assert(getType() == LHS->getType() &&
             "Shift operation should return same type as operands!");
      assert((getType()->isIntegerTy() ||
              (getType()->isVectorTy() && 
               cast<VectorType>(getType())->getElementType()->isIntegerTy())) &&
             "Tried to create a shift operation on a non-integral type!");
      break;
    case And: case Or:
    case Xor:
      assert(getType() == LHS->getType() &&
             "Logical operation should return same type as operands!");
      assert((getType()->isIntegerTy() ||
              (getType()->isVectorTy() && 
               cast<VectorType>(getType())->getElementType()->isIntegerTy())) &&
             "Tried to create a logical operation on a non-integral type!");
      break;
    default:
      break;
    }
  #endif
  }
  
  BinaryOperator *BinaryOperator::Create(BinaryOps Op, Value *S1, Value *S2,
                                         const Twine &Name,
                                         Instruction *InsertBefore) {
    assert(S1->getType() == S2->getType() &&
           "Cannot create binary operator with two operands of differing type!");
    return new BinaryOperator(Op, S1, S2, S1->getType(), Name, InsertBefore);
  }
  
  BinaryOperator *BinaryOperator::Create(BinaryOps Op, Value *S1, Value *S2,
                                         const Twine &Name,
                                         BasicBlock *InsertAtEnd) {
    BinaryOperator *Res = Create(Op, S1, S2, Name);
    InsertAtEnd->getInstList().push_back(Res);
    return Res;
  }
  
  BinaryOperator *BinaryOperator::CreateNeg(Value *Op, const Twine &Name,
                                            Instruction *InsertBefore) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return new BinaryOperator(Instruction::Sub,
                              zero, Op,
                              Op->getType(), Name, InsertBefore);
  }
  
  BinaryOperator *BinaryOperator::CreateNeg(Value *Op, const Twine &Name,
                                            BasicBlock *InsertAtEnd) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return new BinaryOperator(Instruction::Sub,
                              zero, Op,
                              Op->getType(), Name, InsertAtEnd);
  }
  
  BinaryOperator *BinaryOperator::CreateNSWNeg(Value *Op, const Twine &Name,
                                               Instruction *InsertBefore) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return BinaryOperator::CreateNSWSub(zero, Op, Name, InsertBefore);
  }
  
  BinaryOperator *BinaryOperator::CreateNSWNeg(Value *Op, const Twine &Name,
                                               BasicBlock *InsertAtEnd) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return BinaryOperator::CreateNSWSub(zero, Op, Name, InsertAtEnd);
  }
  
  BinaryOperator *BinaryOperator::CreateNUWNeg(Value *Op, const Twine &Name,
                                               Instruction *InsertBefore) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return BinaryOperator::CreateNUWSub(zero, Op, Name, InsertBefore);
  }
  
  BinaryOperator *BinaryOperator::CreateNUWNeg(Value *Op, const Twine &Name,
                                               BasicBlock *InsertAtEnd) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return BinaryOperator::CreateNUWSub(zero, Op, Name, InsertAtEnd);
  }
  
  BinaryOperator *BinaryOperator::CreateFNeg(Value *Op, const Twine &Name,
                                             Instruction *InsertBefore) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return new BinaryOperator(Instruction::FSub, zero, Op,
                              Op->getType(), Name, InsertBefore);
  }
  
  BinaryOperator *BinaryOperator::CreateFNeg(Value *Op, const Twine &Name,
                                             BasicBlock *InsertAtEnd) {
    Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
    return new BinaryOperator(Instruction::FSub, zero, Op,
                              Op->getType(), Name, InsertAtEnd);
  }
  
  BinaryOperator *BinaryOperator::CreateNot(Value *Op, const Twine &Name,
                                            Instruction *InsertBefore) {
    Constant *C = Constant::getAllOnesValue(Op->getType());
    return new BinaryOperator(Instruction::Xor, Op, C,
                              Op->getType(), Name, InsertBefore);
  }
  
  BinaryOperator *BinaryOperator::CreateNot(Value *Op, const Twine &Name,
                                            BasicBlock *InsertAtEnd) {
    Constant *AllOnes = Constant::getAllOnesValue(Op->getType());
    return new BinaryOperator(Instruction::Xor, Op, AllOnes,
                              Op->getType(), Name, InsertAtEnd);
  }
  
  
  // isConstantAllOnes - Helper function for several functions below
  static inline bool isConstantAllOnes(const Value *V) {
    if (const Constant *C = dyn_cast<Constant>(V))
      return C->isAllOnesValue();
    return false;
  }
  
  bool BinaryOperator::isNeg(const Value *V) {
    if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(V))
      if (Bop->getOpcode() == Instruction::Sub)
        if (Constant* C = dyn_cast<Constant>(Bop->getOperand(0)))
          return C->isNegativeZeroValue();
    return false;
  }
  
  bool BinaryOperator::isFNeg(const Value *V, bool IgnoreZeroSign) {
    if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(V))
      if (Bop->getOpcode() == Instruction::FSub)
        if (Constant* C = dyn_cast<Constant>(Bop->getOperand(0))) {
          if (!IgnoreZeroSign)
            IgnoreZeroSign = cast<Instruction>(V)->hasNoSignedZeros();
          return !IgnoreZeroSign ? C->isNegativeZeroValue() : C->isZeroValue();
        }
    return false;
  }
  
  bool BinaryOperator::isNot(const Value *V) {
    if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(V))
      return (Bop->getOpcode() == Instruction::Xor &&
              (isConstantAllOnes(Bop->getOperand(1)) ||
               isConstantAllOnes(Bop->getOperand(0))));
    return false;
  }
  
  Value *BinaryOperator::getNegArgument(Value *BinOp) {
    return cast<BinaryOperator>(BinOp)->getOperand(1);
  }
  
  const Value *BinaryOperator::getNegArgument(const Value *BinOp) {
    return getNegArgument(const_cast<Value*>(BinOp));
  }
  
  Value *BinaryOperator::getFNegArgument(Value *BinOp) {
    return cast<BinaryOperator>(BinOp)->getOperand(1);
  }
  
  const Value *BinaryOperator::getFNegArgument(const Value *BinOp) {
    return getFNegArgument(const_cast<Value*>(BinOp));
  }
  
  Value *BinaryOperator::getNotArgument(Value *BinOp) {
    assert(isNot(BinOp) && "getNotArgument on non-'not' instruction!");
    BinaryOperator *BO = cast<BinaryOperator>(BinOp);
    Value *Op0 = BO->getOperand(0);
    Value *Op1 = BO->getOperand(1);
    if (isConstantAllOnes(Op0)) return Op1;
  
    assert(isConstantAllOnes(Op1));
    return Op0;
  }
  
  const Value *BinaryOperator::getNotArgument(const Value *BinOp) {
    return getNotArgument(const_cast<Value*>(BinOp));
  }
  
  
  // swapOperands - Exchange the two operands to this instruction.  This
  // instruction is safe to use on any binary instruction and does not
  // modify the semantics of the instruction.  If the instruction is
  // order dependent (SetLT f.e.) the opcode is changed.
  //
  bool BinaryOperator::swapOperands() {
    if (!isCommutative())
      return true; // Can't commute operands
    Op<0>().swap(Op<1>());
    return false;
  }
  
  void BinaryOperator::setHasNoUnsignedWrap(bool b) {
    cast<OverflowingBinaryOperator>(this)->setHasNoUnsignedWrap(b);
  }
  
  void BinaryOperator::setHasNoSignedWrap(bool b) {
    cast<OverflowingBinaryOperator>(this)->setHasNoSignedWrap(b);
  }
  
  void BinaryOperator::setIsExact(bool b) {
    cast<PossiblyExactOperator>(this)->setIsExact(b);
  }
  
  bool BinaryOperator::hasNoUnsignedWrap() const {
    return cast<OverflowingBinaryOperator>(this)->hasNoUnsignedWrap();
  }
  
  bool BinaryOperator::hasNoSignedWrap() const {
    return cast<OverflowingBinaryOperator>(this)->hasNoSignedWrap();
  }
  
  bool BinaryOperator::isExact() const {
    return cast<PossiblyExactOperator>(this)->isExact();
  }
  
  void BinaryOperator::copyIRFlags(const Value *V) {
    // Copy the wrapping flags.
    if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
      setHasNoSignedWrap(OB->hasNoSignedWrap());
      setHasNoUnsignedWrap(OB->hasNoUnsignedWrap());
    }
  
    // Copy the exact flag.
    if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
      setIsExact(PE->isExact());
    
    // Copy the fast-math flags.
    if (auto *FP = dyn_cast<FPMathOperator>(V))
      copyFastMathFlags(FP->getFastMathFlags());
  }
  
  void BinaryOperator::andIRFlags(const Value *V) {
    if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
      setHasNoSignedWrap(hasNoSignedWrap() & OB->hasNoSignedWrap());
      setHasNoUnsignedWrap(hasNoUnsignedWrap() & OB->hasNoUnsignedWrap());
    }
    
    if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
      setIsExact(isExact() & PE->isExact());
    
    if (auto *FP = dyn_cast<FPMathOperator>(V)) {
      FastMathFlags FM = getFastMathFlags();
      FM &= FP->getFastMathFlags();
      copyFastMathFlags(FM);
    }
  }
  
  
  //===----------------------------------------------------------------------===//
  //                             FPMathOperator Class
  //===----------------------------------------------------------------------===//
  
  /// getFPAccuracy - Get the maximum error permitted by this operation in ULPs.
  /// An accuracy of 0.0 means that the operation should be performed with the
  /// default precision.
  float FPMathOperator::getFPAccuracy() const {
    const MDNode *MD =
        cast<Instruction>(this)->getMetadata(LLVMContext::MD_fpmath);
    if (!MD)
      return 0.0;
    ConstantFP *Accuracy = mdconst::extract<ConstantFP>(MD->getOperand(0));
    return Accuracy->getValueAPF().convertToFloat();
  }
  
  
  //===----------------------------------------------------------------------===//
  //                                CastInst Class
  //===----------------------------------------------------------------------===//
  
  void CastInst::anchor() {}
  
  // Just determine if this cast only deals with integral->integral conversion.
  bool CastInst::isIntegerCast() const {
    switch (getOpcode()) {
      default: return false;
      case Instruction::ZExt:
      case Instruction::SExt:
      case Instruction::Trunc:
        return true;
      case Instruction::BitCast:
        return getOperand(0)->getType()->isIntegerTy() &&
          getType()->isIntegerTy();
    }
  }
  
  bool CastInst::isLosslessCast() const {
    // Only BitCast can be lossless, exit fast if we're not BitCast
    if (getOpcode() != Instruction::BitCast)
      return false;
  
    // Identity cast is always lossless
    Type* SrcTy = getOperand(0)->getType();
    Type* DstTy = getType();
    if (SrcTy == DstTy)
      return true;
    
    // Pointer to pointer is always lossless.
    if (SrcTy->isPointerTy())
      return DstTy->isPointerTy();
    return false;  // Other types have no identity values
  }
  
  /// This function determines if the CastInst does not require any bits to be
  /// changed in order to effect the cast. Essentially, it identifies cases where
  /// no code gen is necessary for the cast, hence the name no-op cast.  For 
  /// example, the following are all no-op casts:
  /// # bitcast i32* %x to i8*
  /// # bitcast <2 x i32> %x to <4 x i16> 
  /// # ptrtoint i32* %x to i32     ; on 32-bit plaforms only
  /// @brief Determine if the described cast is a no-op.
  bool CastInst::isNoopCast(Instruction::CastOps Opcode,
                            Type *SrcTy,
                            Type *DestTy,
                            Type *IntPtrTy) {
    switch (Opcode) {
      default: llvm_unreachable("Invalid CastOp");
      case Instruction::Trunc:
      case Instruction::ZExt:
      case Instruction::SExt: 
      case Instruction::FPTrunc:
      case Instruction::FPExt:
      case Instruction::UIToFP:
      case Instruction::SIToFP:
      case Instruction::FPToUI:
      case Instruction::FPToSI:
      case Instruction::AddrSpaceCast:
        // TODO: Target informations may give a more accurate answer here.
        return false;
      case Instruction::BitCast:
        return true;  // BitCast never modifies bits.
      case Instruction::PtrToInt:
        return IntPtrTy->getScalarSizeInBits() ==
               DestTy->getScalarSizeInBits();
      case Instruction::IntToPtr:
        return IntPtrTy->getScalarSizeInBits() ==
               SrcTy->getScalarSizeInBits();
    }
  }
  
  /// @brief Determine if a cast is a no-op.
  bool CastInst::isNoopCast(Type *IntPtrTy) const {
    return isNoopCast(getOpcode(), getOperand(0)->getType(), getType(), IntPtrTy);
  }
  
  bool CastInst::isNoopCast(const DataLayout &DL) const {
    Type *PtrOpTy = nullptr;
    if (getOpcode() == Instruction::PtrToInt)
      PtrOpTy = getOperand(0)->getType();
    else if (getOpcode() == Instruction::IntToPtr)
      PtrOpTy = getType();
  
    Type *IntPtrTy =
        PtrOpTy ? DL.getIntPtrType(PtrOpTy) : DL.getIntPtrType(getContext(), 0);
  
    return isNoopCast(getOpcode(), getOperand(0)->getType(), getType(), IntPtrTy);
  }
  
  /// This function determines if a pair of casts can be eliminated and what
  /// opcode should be used in the elimination. This assumes that there are two
  /// instructions like this:
  /// *  %F = firstOpcode SrcTy %x to MidTy
  /// *  %S = secondOpcode MidTy %F to DstTy
  /// The function returns a resultOpcode so these two casts can be replaced with:
  /// *  %Replacement = resultOpcode %SrcTy %x to DstTy
  /// If no such cast is permited, the function returns 0.
  unsigned CastInst::isEliminableCastPair(
    Instruction::CastOps firstOp, Instruction::CastOps secondOp,
    Type *SrcTy, Type *MidTy, Type *DstTy, Type *SrcIntPtrTy, Type *MidIntPtrTy,
    Type *DstIntPtrTy) {
    // Define the 144 possibilities for these two cast instructions. The values
    // in this matrix determine what to do in a given situation and select the
    // case in the switch below.  The rows correspond to firstOp, the columns 
    // correspond to secondOp.  In looking at the table below, keep in  mind
    // the following cast properties:
    //
    //          Size Compare       Source               Destination
    // Operator  Src ? Size   Type       Sign         Type       Sign
    // -------- ------------ -------------------   ---------------------
    // TRUNC         >       Integer      Any        Integral     Any
    // ZEXT          <       Integral   Unsigned     Integer      Any
    // SEXT          <       Integral    Signed      Integer      Any
    // FPTOUI       n/a      FloatPt      n/a        Integral   Unsigned
    // FPTOSI       n/a      FloatPt      n/a        Integral    Signed
    // UITOFP       n/a      Integral   Unsigned     FloatPt      n/a
    // SITOFP       n/a      Integral    Signed      FloatPt      n/a
    // FPTRUNC       >       FloatPt      n/a        FloatPt      n/a
    // FPEXT         <       FloatPt      n/a        FloatPt      n/a
    // PTRTOINT     n/a      Pointer      n/a        Integral   Unsigned
    // INTTOPTR     n/a      Integral   Unsigned     Pointer      n/a
    // BITCAST       =       FirstClass   n/a       FirstClass    n/a
    // ADDRSPCST    n/a      Pointer      n/a        Pointer      n/a
    //
    // NOTE: some transforms are safe, but we consider them to be non-profitable.
    // For example, we could merge "fptoui double to i32" + "zext i32 to i64",
    // into "fptoui double to i64", but this loses information about the range
    // of the produced value (we no longer know the top-part is all zeros).
    // Further this conversion is often much more expensive for typical hardware,
    // and causes issues when building libgcc.  We disallow fptosi+sext for the
    // same reason.
    const unsigned numCastOps =
      Instruction::CastOpsEnd - Instruction::CastOpsBegin;
    static const uint8_t CastResults[numCastOps][numCastOps] = {
      // T        F  F  U  S  F  F  P  I  B  A  -+
      // R  Z  S  P  P  I  I  T  P  2  N  T  S   |
      // U  E  E  2  2  2  2  R  E  I  T  C  C   +- secondOp
      // N  X  X  U  S  F  F  N  X  N  2  V  V   |
      // C  T  T  I  I  P  P  C  T  T  P  T  T  -+
      {  1, 0, 0,99,99, 0, 0,99,99,99, 0, 3, 0}, // Trunc         -+
      {  8, 1, 9,99,99, 2,17,99,99,99, 2, 3, 0}, // ZExt           |
      {  8, 0, 1,99,99, 0, 2,99,99,99, 0, 3, 0}, // SExt           |
      {  0, 0, 0,99,99, 0, 0,99,99,99, 0, 3, 0}, // FPToUI         |
      {  0, 0, 0,99,99, 0, 0,99,99,99, 0, 3, 0}, // FPToSI         |
      { 99,99,99, 0, 0,99,99, 0, 0,99,99, 4, 0}, // UIToFP         +- firstOp
      { 99,99,99, 0, 0,99,99, 0, 0,99,99, 4, 0}, // SIToFP         |
      { 99,99,99, 0, 0,99,99, 0, 0,99,99, 4, 0}, // FPTrunc        |
      { 99,99,99, 2, 2,99,99,10, 2,99,99, 4, 0}, // FPExt          |
      {  1, 0, 0,99,99, 0, 0,99,99,99, 7, 3, 0}, // PtrToInt       |
      { 99,99,99,99,99,99,99,99,99,11,99,15, 0}, // IntToPtr       |
      {  5, 5, 5, 6, 6, 5, 5, 6, 6,16, 5, 1,14}, // BitCast        |
      {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,13,12}, // AddrSpaceCast -+
    };
  
    // If either of the casts are a bitcast from scalar to vector, disallow the
    // merging. However, bitcast of A->B->A are allowed.
    bool isFirstBitcast  = (firstOp == Instruction::BitCast);
    bool isSecondBitcast = (secondOp == Instruction::BitCast);
    bool chainedBitcast  = (SrcTy == DstTy && isFirstBitcast && isSecondBitcast);
  
    // Check if any of the bitcasts convert scalars<->vectors.
    if ((isFirstBitcast  && isa<VectorType>(SrcTy) != isa<VectorType>(MidTy)) ||
        (isSecondBitcast && isa<VectorType>(MidTy) != isa<VectorType>(DstTy)))
      // Unless we are bitcasing to the original type, disallow optimizations.
      if (!chainedBitcast) return 0;
  
    int ElimCase = CastResults[firstOp-Instruction::CastOpsBegin]
                              [secondOp-Instruction::CastOpsBegin];
    switch (ElimCase) {
      case 0: 
        // Categorically disallowed.
        return 0;
      case 1: 
        // Allowed, use first cast's opcode.
        return firstOp;
      case 2: 
        // Allowed, use second cast's opcode.
        return secondOp;
      case 3: 
        // No-op cast in second op implies firstOp as long as the DestTy
        // is integer and we are not converting between a vector and a
        // non-vector type.
        if (!SrcTy->isVectorTy() && DstTy->isIntegerTy())
          return firstOp;
        return 0;
      case 4:
        // No-op cast in second op implies firstOp as long as the DestTy
        // is floating point.
        if (DstTy->isFloatingPointTy())
          return firstOp;
        return 0;
      case 5: 
        // No-op cast in first op implies secondOp as long as the SrcTy
        // is an integer.
        if (SrcTy->isIntegerTy())
          return secondOp;
        return 0;
      case 6:
        // No-op cast in first op implies secondOp as long as the SrcTy
        // is a floating point.
        if (SrcTy->isFloatingPointTy())
          return secondOp;
        return 0;
      case 7: {
        // Cannot simplify if address spaces are different!
        if (SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace())
          return 0;
  
        unsigned MidSize = MidTy->getScalarSizeInBits();
        // We can still fold this without knowing the actual sizes as long we
        // know that the intermediate pointer is the largest possible
        // pointer size.
        // FIXME: Is this always true?
        if (MidSize == 64)
          return Instruction::BitCast;
  
        // ptrtoint, inttoptr -> bitcast (ptr -> ptr) if int size is >= ptr size.
        if (!SrcIntPtrTy || DstIntPtrTy != SrcIntPtrTy)
          return 0;
        unsigned PtrSize = SrcIntPtrTy->getScalarSizeInBits();
        if (MidSize >= PtrSize)
          return Instruction::BitCast;
        return 0;
      }
      case 8: {
        // ext, trunc -> bitcast,    if the SrcTy and DstTy are same size
        // ext, trunc -> ext,        if sizeof(SrcTy) < sizeof(DstTy)
        // ext, trunc -> trunc,      if sizeof(SrcTy) > sizeof(DstTy)
        unsigned SrcSize = SrcTy->getScalarSizeInBits();
        unsigned DstSize = DstTy->getScalarSizeInBits();
        if (SrcSize == DstSize)
          return Instruction::BitCast;
        else if (SrcSize < DstSize)
          return firstOp;
        return secondOp;
      }
      case 9:
        // zext, sext -> zext, because sext can't sign extend after zext
        return Instruction::ZExt;
      case 10:
        // fpext followed by ftrunc is allowed if the bit size returned to is
        // the same as the original, in which case its just a bitcast
        if (SrcTy == DstTy)
          return Instruction::BitCast;
        return 0; // If the types are not the same we can't eliminate it.
      case 11: {
        // inttoptr, ptrtoint -> bitcast if SrcSize<=PtrSize and SrcSize==DstSize
        if (!MidIntPtrTy)
          return 0;
        unsigned PtrSize = MidIntPtrTy->getScalarSizeInBits();
        unsigned SrcSize = SrcTy->getScalarSizeInBits();
        unsigned DstSize = DstTy->getScalarSizeInBits();
        if (SrcSize <= PtrSize && SrcSize == DstSize)
          return Instruction::BitCast;
        return 0;
      }
      case 12: {
        // addrspacecast, addrspacecast -> bitcast,       if SrcAS == DstAS
        // addrspacecast, addrspacecast -> addrspacecast, if SrcAS != DstAS
        if (SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace())
          return Instruction::AddrSpaceCast;
        return Instruction::BitCast;
      }
      case 13:
        // FIXME: this state can be merged with (1), but the following assert
        // is useful to check the correcteness of the sequence due to semantic
        // change of bitcast.
        assert(
          SrcTy->isPtrOrPtrVectorTy() &&
          MidTy->isPtrOrPtrVectorTy() &&
          DstTy->isPtrOrPtrVectorTy() &&
          SrcTy->getPointerAddressSpace() != MidTy->getPointerAddressSpace() &&
          MidTy->getPointerAddressSpace() == DstTy->getPointerAddressSpace() &&
          "Illegal addrspacecast, bitcast sequence!");
        // Allowed, use first cast's opcode
        return firstOp;
      case 14:
        // bitcast, addrspacecast -> addrspacecast if the element type of
        // bitcast's source is the same as that of addrspacecast's destination.
        if (SrcTy->getPointerElementType() == DstTy->getPointerElementType())
          return Instruction::AddrSpaceCast;
        return 0;
  
      case 15:
        // FIXME: this state can be merged with (1), but the following assert
        // is useful to check the correcteness of the sequence due to semantic
        // change of bitcast.
        assert(
          SrcTy->isIntOrIntVectorTy() &&
          MidTy->isPtrOrPtrVectorTy() &&
          DstTy->isPtrOrPtrVectorTy() &&
          MidTy->getPointerAddressSpace() == DstTy->getPointerAddressSpace() &&
          "Illegal inttoptr, bitcast sequence!");
        // Allowed, use first cast's opcode
        return firstOp;
      case 16:
        // FIXME: this state can be merged with (2), but the following assert
        // is useful to check the correcteness of the sequence due to semantic
        // change of bitcast.
        assert(
          SrcTy->isPtrOrPtrVectorTy() &&
          MidTy->isPtrOrPtrVectorTy() &&
          DstTy->isIntOrIntVectorTy() &&
          SrcTy->getPointerAddressSpace() == MidTy->getPointerAddressSpace() &&
          "Illegal bitcast, ptrtoint sequence!");
        // Allowed, use second cast's opcode
        return secondOp;
      case 17:
        // (sitofp (zext x)) -> (uitofp x)
        return Instruction::UIToFP;
      case 99: 
        // Cast combination can't happen (error in input). This is for all cases
        // where the MidTy is not the same for the two cast instructions.
        llvm_unreachable("Invalid Cast Combination");
      default:
        llvm_unreachable("Error in CastResults table!!!");
    }
  }
  
  CastInst *CastInst::Create(Instruction::CastOps op, Value *S, Type *Ty, 
    const Twine &Name, Instruction *InsertBefore) {
    assert(castIsValid(op, S, Ty) && "Invalid cast!");
    // Construct and return the appropriate CastInst subclass
    switch (op) {
    case Trunc:         return new TruncInst         (S, Ty, Name, InsertBefore);
    case ZExt:          return new ZExtInst          (S, Ty, Name, InsertBefore);
    case SExt:          return new SExtInst          (S, Ty, Name, InsertBefore);
    case FPTrunc:       return new FPTruncInst       (S, Ty, Name, InsertBefore);
    case FPExt:         return new FPExtInst         (S, Ty, Name, InsertBefore);
    case UIToFP:        return new UIToFPInst        (S, Ty, Name, InsertBefore);
    case SIToFP:        return new SIToFPInst        (S, Ty, Name, InsertBefore);
    case FPToUI:        return new FPToUIInst        (S, Ty, Name, InsertBefore);
    case FPToSI:        return new FPToSIInst        (S, Ty, Name, InsertBefore);
    case PtrToInt:      return new PtrToIntInst      (S, Ty, Name, InsertBefore);
    case IntToPtr:      return new IntToPtrInst      (S, Ty, Name, InsertBefore);
    case BitCast:       return new BitCastInst       (S, Ty, Name, InsertBefore);
    case AddrSpaceCast: return new AddrSpaceCastInst (S, Ty, Name, InsertBefore);
    default: llvm_unreachable("Invalid opcode provided");
    }
  }
  
  CastInst *CastInst::Create(Instruction::CastOps op, Value *S, Type *Ty,
    const Twine &Name, BasicBlock *InsertAtEnd) {
    assert(castIsValid(op, S, Ty) && "Invalid cast!");
    // Construct and return the appropriate CastInst subclass
    switch (op) {
    case Trunc:         return new TruncInst         (S, Ty, Name, InsertAtEnd);
    case ZExt:          return new ZExtInst          (S, Ty, Name, InsertAtEnd);
    case SExt:          return new SExtInst          (S, Ty, Name, InsertAtEnd);
    case FPTrunc:       return new FPTruncInst       (S, Ty, Name, InsertAtEnd);
    case FPExt:         return new FPExtInst         (S, Ty, Name, InsertAtEnd);
    case UIToFP:        return new UIToFPInst        (S, Ty, Name, InsertAtEnd);
    case SIToFP:        return new SIToFPInst        (S, Ty, Name, InsertAtEnd);
    case FPToUI:        return new FPToUIInst        (S, Ty, Name, InsertAtEnd);
    case FPToSI:        return new FPToSIInst        (S, Ty, Name, InsertAtEnd);
    case PtrToInt:      return new PtrToIntInst      (S, Ty, Name, InsertAtEnd);
    case IntToPtr:      return new IntToPtrInst      (S, Ty, Name, InsertAtEnd);
    case BitCast:       return new BitCastInst       (S, Ty, Name, InsertAtEnd);
    case AddrSpaceCast: return new AddrSpaceCastInst (S, Ty, Name, InsertAtEnd);
    default: llvm_unreachable("Invalid opcode provided");
    }
  }
  
  CastInst *CastInst::CreateZExtOrBitCast(Value *S, Type *Ty, 
                                          const Twine &Name,
                                          Instruction *InsertBefore) {
    if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
      return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
    return Create(Instruction::ZExt, S, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreateZExtOrBitCast(Value *S, Type *Ty, 
                                          const Twine &Name,
                                          BasicBlock *InsertAtEnd) {
    if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
      return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
    return Create(Instruction::ZExt, S, Ty, Name, InsertAtEnd);
  }
  
  CastInst *CastInst::CreateSExtOrBitCast(Value *S, Type *Ty, 
                                          const Twine &Name,
                                          Instruction *InsertBefore) {
    if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
      return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
    return Create(Instruction::SExt, S, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreateSExtOrBitCast(Value *S, Type *Ty, 
                                          const Twine &Name,
                                          BasicBlock *InsertAtEnd) {
    if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
      return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
    return Create(Instruction::SExt, S, Ty, Name, InsertAtEnd);
  }
  
  CastInst *CastInst::CreateTruncOrBitCast(Value *S, Type *Ty,
                                           const Twine &Name,
                                           Instruction *InsertBefore) {
    if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
      return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
    return Create(Instruction::Trunc, S, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreateTruncOrBitCast(Value *S, Type *Ty,
                                           const Twine &Name, 
                                           BasicBlock *InsertAtEnd) {
    if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
      return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
    return Create(Instruction::Trunc, S, Ty, Name, InsertAtEnd);
  }
  
  CastInst *CastInst::CreatePointerCast(Value *S, Type *Ty,
                                        const Twine &Name,
                                        BasicBlock *InsertAtEnd) {
    assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
    assert((Ty->isIntOrIntVectorTy() || Ty->isPtrOrPtrVectorTy()) &&
           "Invalid cast");
    assert(Ty->isVectorTy() == S->getType()->isVectorTy() && "Invalid cast");
    assert((!Ty->isVectorTy() ||
            Ty->getVectorNumElements() == S->getType()->getVectorNumElements()) &&
           "Invalid cast");
  
    if (Ty->isIntOrIntVectorTy())
      return Create(Instruction::PtrToInt, S, Ty, Name, InsertAtEnd);
  
    return CreatePointerBitCastOrAddrSpaceCast(S, Ty, Name, InsertAtEnd);
  }
  
  /// @brief Create a BitCast or a PtrToInt cast instruction
  CastInst *CastInst::CreatePointerCast(Value *S, Type *Ty,
                                        const Twine &Name,
                                        Instruction *InsertBefore) {
    assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
    assert((Ty->isIntOrIntVectorTy() || Ty->isPtrOrPtrVectorTy()) &&
           "Invalid cast");
    assert(Ty->isVectorTy() == S->getType()->isVectorTy() && "Invalid cast");
    assert((!Ty->isVectorTy() ||
            Ty->getVectorNumElements() == S->getType()->getVectorNumElements()) &&
           "Invalid cast");
  
    if (Ty->isIntOrIntVectorTy())
      return Create(Instruction::PtrToInt, S, Ty, Name, InsertBefore);
  
    return CreatePointerBitCastOrAddrSpaceCast(S, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreatePointerBitCastOrAddrSpaceCast(
    Value *S, Type *Ty,
    const Twine &Name,
    BasicBlock *InsertAtEnd) {
    assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
    assert(Ty->isPtrOrPtrVectorTy() && "Invalid cast");
  
    if (S->getType()->getPointerAddressSpace() != Ty->getPointerAddressSpace())
      return Create(Instruction::AddrSpaceCast, S, Ty, Name, InsertAtEnd);
  
    return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
  }
  
  CastInst *CastInst::CreatePointerBitCastOrAddrSpaceCast(
    Value *S, Type *Ty,
    const Twine &Name,
    Instruction *InsertBefore) {
    assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
    assert(Ty->isPtrOrPtrVectorTy() && "Invalid cast");
  
    if (S->getType()->getPointerAddressSpace() != Ty->getPointerAddressSpace())
      return Create(Instruction::AddrSpaceCast, S, Ty, Name, InsertBefore);
  
    return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreateBitOrPointerCast(Value *S, Type *Ty,
                                             const Twine &Name,
                                             Instruction *InsertBefore) {
    if (S->getType()->isPointerTy() && Ty->isIntegerTy())
      return Create(Instruction::PtrToInt, S, Ty, Name, InsertBefore);
    if (S->getType()->isIntegerTy() && Ty->isPointerTy())
      return Create(Instruction::IntToPtr, S, Ty, Name, InsertBefore);
  
    return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreateIntegerCast(Value *C, Type *Ty,
                                        bool isSigned, const Twine &Name,
                                        Instruction *InsertBefore) {
    assert(C->getType()->isIntOrIntVectorTy() && Ty->isIntOrIntVectorTy() &&
           "Invalid integer cast");
    unsigned SrcBits = C->getType()->getScalarSizeInBits();
    unsigned DstBits = Ty->getScalarSizeInBits();
    Instruction::CastOps opcode =
      (SrcBits == DstBits ? Instruction::BitCast :
       (SrcBits > DstBits ? Instruction::Trunc :
        (isSigned ? Instruction::SExt : Instruction::ZExt)));
    return Create(opcode, C, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreateIntegerCast(Value *C, Type *Ty, 
                                        bool isSigned, const Twine &Name,
                                        BasicBlock *InsertAtEnd) {
    assert(C->getType()->isIntOrIntVectorTy() && Ty->isIntOrIntVectorTy() &&
           "Invalid cast");
    unsigned SrcBits = C->getType()->getScalarSizeInBits();
    unsigned DstBits = Ty->getScalarSizeInBits();
    Instruction::CastOps opcode =
      (SrcBits == DstBits ? Instruction::BitCast :
       (SrcBits > DstBits ? Instruction::Trunc :
        (isSigned ? Instruction::SExt : Instruction::ZExt)));
    return Create(opcode, C, Ty, Name, InsertAtEnd);
  }
  
  CastInst *CastInst::CreateFPCast(Value *C, Type *Ty, 
                                   const Twine &Name, 
                                   Instruction *InsertBefore) {
    assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
           "Invalid cast");
    unsigned SrcBits = C->getType()->getScalarSizeInBits();
    unsigned DstBits = Ty->getScalarSizeInBits();
    Instruction::CastOps opcode =
      (SrcBits == DstBits ? Instruction::BitCast :
       (SrcBits > DstBits ? Instruction::FPTrunc : Instruction::FPExt));
    return Create(opcode, C, Ty, Name, InsertBefore);
  }
  
  CastInst *CastInst::CreateFPCast(Value *C, Type *Ty, 
                                   const Twine &Name, 
                                   BasicBlock *InsertAtEnd) {
    assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
           "Invalid cast");
    unsigned SrcBits = C->getType()->getScalarSizeInBits();
    unsigned DstBits = Ty->getScalarSizeInBits();
    Instruction::CastOps opcode =
      (SrcBits == DstBits ? Instruction::BitCast :
       (SrcBits > DstBits ? Instruction::FPTrunc : Instruction::FPExt));
    return Create(opcode, C, Ty, Name, InsertAtEnd);
  }
  
  // Check whether it is valid to call getCastOpcode for these types.
  // This routine must be kept in sync with getCastOpcode.
  bool CastInst::isCastable(Type *SrcTy, Type *DestTy) {
    if (!SrcTy->isFirstClassType() || !DestTy->isFirstClassType())
      return false;
  
    if (SrcTy == DestTy)
      return true;
  
    if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy))
      if (VectorType *DestVecTy = dyn_cast<VectorType>(DestTy))
        if (SrcVecTy->getNumElements() == DestVecTy->getNumElements()) {
          // An element by element cast.  Valid if casting the elements is valid.
          SrcTy = SrcVecTy->getElementType();
          DestTy = DestVecTy->getElementType();
        }
  
    // Get the bit sizes, we'll need these
    unsigned SrcBits = SrcTy->getPrimitiveSizeInBits();   // 0 for ptr
    unsigned DestBits = DestTy->getPrimitiveSizeInBits(); // 0 for ptr
  
    // Run through the possibilities ...
    if (DestTy->isIntegerTy()) {               // Casting to integral
      if (SrcTy->isIntegerTy())                // Casting from integral
          return true;
      if (SrcTy->isFloatingPointTy())   // Casting from floating pt
        return true;
      if (SrcTy->isVectorTy())          // Casting from vector
        return DestBits == SrcBits;
                                        // Casting from something else
      return SrcTy->isPointerTy();
    } 
    if (DestTy->isFloatingPointTy()) {  // Casting to floating pt
      if (SrcTy->isIntegerTy())                // Casting from integral
        return true;
      if (SrcTy->isFloatingPointTy())   // Casting from floating pt
        return true;
      if (SrcTy->isVectorTy())          // Casting from vector
        return DestBits == SrcBits;
                                      // Casting from something else
      return false;
    }
    if (DestTy->isVectorTy())         // Casting to vector
      return DestBits == SrcBits;
    if (DestTy->isPointerTy()) {        // Casting to pointer
      if (SrcTy->isPointerTy())                // Casting from pointer
        return true;
      return SrcTy->isIntegerTy();             // Casting from integral
    } 
    if (DestTy->isX86_MMXTy()) {
      if (SrcTy->isVectorTy())
        return DestBits == SrcBits;       // 64-bit vector to MMX
      return false;
    }                                    // Casting to something else
    return false;
  }
  
  bool CastInst::isBitCastable(Type *SrcTy, Type *DestTy) {
    if (!SrcTy->isFirstClassType() || !DestTy->isFirstClassType())
      return false;
  
    if (SrcTy == DestTy)
      return true;
  
    if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy)) {
      if (VectorType *DestVecTy = dyn_cast<VectorType>(DestTy)) {
        if (SrcVecTy->getNumElements() == DestVecTy->getNumElements()) {
          // An element by element cast. Valid if casting the elements is valid.
          SrcTy = SrcVecTy->getElementType();
          DestTy = DestVecTy->getElementType();
        }
      }
    }
  
    if (PointerType *DestPtrTy = dyn_cast<PointerType>(DestTy)) {
      if (PointerType *SrcPtrTy = dyn_cast<PointerType>(SrcTy)) {
        return SrcPtrTy->getAddressSpace() == DestPtrTy->getAddressSpace();
      }
    }
  
    unsigned SrcBits = SrcTy->getPrimitiveSizeInBits();   // 0 for ptr
    unsigned DestBits = DestTy->getPrimitiveSizeInBits(); // 0 for ptr
  
    // Could still have vectors of pointers if the number of elements doesn't
    // match
    if (SrcBits == 0 || DestBits == 0)
      return false;
  
    if (SrcBits != DestBits)
      return false;
  
    if (DestTy->isX86_MMXTy() || SrcTy->isX86_MMXTy())
      return false;
  
    return true;
  }
  
  bool CastInst::isBitOrNoopPointerCastable(Type *SrcTy, Type *DestTy,
                                            const DataLayout &DL) {
    if (auto *PtrTy = dyn_cast<PointerType>(SrcTy))
      if (auto *IntTy = dyn_cast<IntegerType>(DestTy))
        return IntTy->getBitWidth() == DL.getPointerTypeSizeInBits(PtrTy);
    if (auto *PtrTy = dyn_cast<PointerType>(DestTy))
      if (auto *IntTy = dyn_cast<IntegerType>(SrcTy))
        return IntTy->getBitWidth() == DL.getPointerTypeSizeInBits(PtrTy);
  
    return isBitCastable(SrcTy, DestTy);
  }
  
  // Provide a way to get a "cast" where the cast opcode is inferred from the
  // types and size of the operand. This, basically, is a parallel of the
  // logic in the castIsValid function below.  This axiom should hold:
  //   castIsValid( getCastOpcode(Val, Ty), Val, Ty)
  // should not assert in castIsValid. In other words, this produces a "correct"
  // casting opcode for the arguments passed to it.
  // This routine must be kept in sync with isCastable.
  Instruction::CastOps
  CastInst::getCastOpcode(
    const Value *Src, bool SrcIsSigned, Type *DestTy, bool DestIsSigned) {
    Type *SrcTy = Src->getType();
  
    assert(SrcTy->isFirstClassType() && DestTy->isFirstClassType() &&
           "Only first class types are castable!");
  
    if (SrcTy == DestTy)
      return BitCast;
  
    // FIXME: Check address space sizes here
    if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy))
      if (VectorType *DestVecTy = dyn_cast<VectorType>(DestTy))
        if (SrcVecTy->getNumElements() == DestVecTy->getNumElements()) {
          // An element by element cast.  Find the appropriate opcode based on the
          // element types.
          SrcTy = SrcVecTy->getElementType();
          DestTy = DestVecTy->getElementType();
        }
  
    // Get the bit sizes, we'll need these
    unsigned SrcBits = SrcTy->getPrimitiveSizeInBits();   // 0 for ptr
    unsigned DestBits = DestTy->getPrimitiveSizeInBits(); // 0 for ptr
  
    // Run through the possibilities ...
    if (DestTy->isIntegerTy()) {                      // Casting to integral
      if (SrcTy->isIntegerTy()) {                     // Casting from integral
        if (DestBits < SrcBits)
          return Trunc;                               // int -> smaller int
        else if (DestBits > SrcBits) {                // its an extension
          if (SrcIsSigned)
            return SExt;                              // signed -> SEXT
          else
            return ZExt;                              // unsigned -> ZEXT
        } else {
          return BitCast;                             // Same size, No-op cast
        }
      } else if (SrcTy->isFloatingPointTy()) {        // Casting from floating pt
        if (DestIsSigned) 
          return FPToSI;                              // FP -> sint
        else
          return FPToUI;                              // FP -> uint 
      } else if (SrcTy->isVectorTy()) {
        assert(DestBits == SrcBits &&
               "Casting vector to integer of different width");
        return BitCast;                             // Same size, no-op cast
      } else {
        assert(SrcTy->isPointerTy() &&
               "Casting from a value that is not first-class type");
        return PtrToInt;                              // ptr -> int
      }
    } else if (DestTy->isFloatingPointTy()) {         // Casting to floating pt
      if (SrcTy->isIntegerTy()) {                     // Casting from integral
        if (SrcIsSigned)
          return SIToFP;                              // sint -> FP
        else
          return UIToFP;                              // uint -> FP
      } else if (SrcTy->isFloatingPointTy()) {        // Casting from floating pt
        if (DestBits < SrcBits) {
          return FPTrunc;                             // FP -> smaller FP
        } else if (DestBits > SrcBits) {
          return FPExt;                               // FP -> larger FP
        } else  {
          return BitCast;                             // same size, no-op cast
        }
      } else if (SrcTy->isVectorTy()) {
        assert(DestBits == SrcBits &&
               "Casting vector to floating point of different width");
        return BitCast;                             // same size, no-op cast
      }
      llvm_unreachable("Casting pointer or non-first class to float");
    } else if (DestTy->isVectorTy()) {
      assert(DestBits == SrcBits &&
             "Illegal cast to vector (wrong type or size)");
      return BitCast;
    } else if (DestTy->isPointerTy()) {
      if (SrcTy->isPointerTy()) {
        if (DestTy->getPointerAddressSpace() != SrcTy->getPointerAddressSpace())
          return AddrSpaceCast;
        return BitCast;                               // ptr -> ptr
      } else if (SrcTy->isIntegerTy()) {
        return IntToPtr;                              // int -> ptr
      }
      llvm_unreachable("Casting pointer to other than pointer or int");
    } else if (DestTy->isX86_MMXTy()) {
      if (SrcTy->isVectorTy()) {
        assert(DestBits == SrcBits && "Casting vector of wrong width to X86_MMX");
        return BitCast;                               // 64-bit vector to MMX
      }
      llvm_unreachable("Illegal cast to X86_MMX");
    }
    llvm_unreachable("Casting to type that is not first-class");
  }
  
  //===----------------------------------------------------------------------===//
  //                    CastInst SubClass Constructors
  //===----------------------------------------------------------------------===//
  
  /// Check that the construction parameters for a CastInst are correct. This
  /// could be broken out into the separate constructors but it is useful to have
  /// it in one place and to eliminate the redundant code for getting the sizes
  /// of the types involved.
  bool 
  CastInst::castIsValid(Instruction::CastOps op, Value *S, Type *DstTy) {
  
    // Check for type sanity on the arguments
    Type *SrcTy = S->getType();
  
    if (!SrcTy->isFirstClassType() || !DstTy->isFirstClassType() ||
        SrcTy->isAggregateType() || DstTy->isAggregateType())
      return false;
  
    // Get the size of the types in bits, we'll need this later
    unsigned SrcBitSize = SrcTy->getScalarSizeInBits();
    unsigned DstBitSize = DstTy->getScalarSizeInBits();
  
    // If these are vector types, get the lengths of the vectors (using zero for
    // scalar types means that checking that vector lengths match also checks that
    // scalars are not being converted to vectors or vectors to scalars).
    unsigned SrcLength = SrcTy->isVectorTy() ?
      cast<VectorType>(SrcTy)->getNumElements() : 0;
    unsigned DstLength = DstTy->isVectorTy() ?
      cast<VectorType>(DstTy)->getNumElements() : 0;
  
    // Switch on the opcode provided
    switch (op) {
    default: return false; // This is an input error
    case Instruction::Trunc:
      return SrcTy->isIntOrIntVectorTy() && DstTy->isIntOrIntVectorTy() &&
        SrcLength == DstLength && SrcBitSize > DstBitSize;
    case Instruction::ZExt:
      return SrcTy->isIntOrIntVectorTy() && DstTy->isIntOrIntVectorTy() &&
        SrcLength == DstLength && SrcBitSize < DstBitSize;
    case Instruction::SExt: 
      return SrcTy->isIntOrIntVectorTy() && DstTy->isIntOrIntVectorTy() &&
        SrcLength == DstLength && SrcBitSize < DstBitSize;
    case Instruction::FPTrunc:
      return SrcTy->isFPOrFPVectorTy() && DstTy->isFPOrFPVectorTy() &&
        SrcLength == DstLength && SrcBitSize > DstBitSize;
    case Instruction::FPExt:
      return SrcTy->isFPOrFPVectorTy() && DstTy->isFPOrFPVectorTy() &&
        SrcLength == DstLength && SrcBitSize < DstBitSize;
    case Instruction::UIToFP:
    case Instruction::SIToFP:
      return SrcTy->isIntOrIntVectorTy() && DstTy->isFPOrFPVectorTy() &&
        SrcLength == DstLength;
    case Instruction::FPToUI:
    case Instruction::FPToSI:
      return SrcTy->isFPOrFPVectorTy() && DstTy->isIntOrIntVectorTy() &&
        SrcLength == DstLength;
    case Instruction::PtrToInt:
      if (isa<VectorType>(SrcTy) != isa<VectorType>(DstTy))
        return false;
      if (VectorType *VT = dyn_cast<VectorType>(SrcTy))
        if (VT->getNumElements() != cast<VectorType>(DstTy)->getNumElements())
          return false;
      return SrcTy->getScalarType()->isPointerTy() &&
             DstTy->getScalarType()->isIntegerTy();
    case Instruction::IntToPtr:
      if (isa<VectorType>(SrcTy) != isa<VectorType>(DstTy))
        return false;
      if (VectorType *VT = dyn_cast<VectorType>(SrcTy))
        if (VT->getNumElements() != cast<VectorType>(DstTy)->getNumElements())
          return false;
      return SrcTy->getScalarType()->isIntegerTy() &&
             DstTy->getScalarType()->isPointerTy();
    case Instruction::BitCast: {
      PointerType *SrcPtrTy = dyn_cast<PointerType>(SrcTy->getScalarType());
      PointerType *DstPtrTy = dyn_cast<PointerType>(DstTy->getScalarType());
  
      // BitCast implies a no-op cast of type only. No bits change.
      // However, you can't cast pointers to anything but pointers.
      if (!SrcPtrTy != !DstPtrTy)
        return false;
  
      // For non-pointer cases, the cast is okay if the source and destination bit
      // widths are identical.
      if (!SrcPtrTy)
        return SrcTy->getPrimitiveSizeInBits() == DstTy->getPrimitiveSizeInBits();
  
      // If both are pointers then the address spaces must match.
      if (SrcPtrTy->getAddressSpace() != DstPtrTy->getAddressSpace())
        return false;
  
      // A vector of pointers must have the same number of elements.
      if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy)) {
        if (VectorType *DstVecTy = dyn_cast<VectorType>(DstTy))
          return (SrcVecTy->getNumElements() == DstVecTy->getNumElements());
  
        return false;
      }
  
      return true;
    }
    case Instruction::AddrSpaceCast: {
      PointerType *SrcPtrTy = dyn_cast<PointerType>(SrcTy->getScalarType());
      if (!SrcPtrTy)
        return false;
  
      PointerType *DstPtrTy = dyn_cast<PointerType>(DstTy->getScalarType());
      if (!DstPtrTy)
        return false;
  
      if (SrcPtrTy->getAddressSpace() == DstPtrTy->getAddressSpace())
        return false;
  
      if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy)) {
        if (VectorType *DstVecTy = dyn_cast<VectorType>(DstTy))
          return (SrcVecTy->getNumElements() == DstVecTy->getNumElements());
  
        return false;
      }
  
      return true;
    }
    }
  }
  
  TruncInst::TruncInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, Trunc, S, Name, InsertBefore) {
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal Trunc");
  }
  
  TruncInst::TruncInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, Trunc, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal Trunc");
  }
  
  ZExtInst::ZExtInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  )  : CastInst(Ty, ZExt, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal ZExt");
  }
  
  ZExtInst::ZExtInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  )  : CastInst(Ty, ZExt, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal ZExt");
  }
  SExtInst::SExtInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, SExt, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal SExt");
  }
  
  SExtInst::SExtInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  )  : CastInst(Ty, SExt, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal SExt");
  }
  
  FPTruncInst::FPTruncInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, FPTrunc, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPTrunc");
  }
  
  FPTruncInst::FPTruncInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, FPTrunc, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPTrunc");
  }
  
  FPExtInst::FPExtInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, FPExt, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPExt");
  }
  
  FPExtInst::FPExtInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, FPExt, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPExt");
  }
  
  UIToFPInst::UIToFPInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, UIToFP, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal UIToFP");
  }
  
  UIToFPInst::UIToFPInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, UIToFP, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal UIToFP");
  }
  
  SIToFPInst::SIToFPInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, SIToFP, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal SIToFP");
  }
  
  SIToFPInst::SIToFPInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, SIToFP, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal SIToFP");
  }
  
  FPToUIInst::FPToUIInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, FPToUI, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToUI");
  }
  
  FPToUIInst::FPToUIInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, FPToUI, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToUI");
  }
  
  FPToSIInst::FPToSIInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, FPToSI, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToSI");
  }
  
  FPToSIInst::FPToSIInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, FPToSI, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToSI");
  }
  
  PtrToIntInst::PtrToIntInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, PtrToInt, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal PtrToInt");
  }
  
  PtrToIntInst::PtrToIntInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, PtrToInt, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal PtrToInt");
  }
  
  IntToPtrInst::IntToPtrInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, IntToPtr, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal IntToPtr");
  }
  
  IntToPtrInst::IntToPtrInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, IntToPtr, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal IntToPtr");
  }
  
  BitCastInst::BitCastInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, BitCast, S, Name, InsertBefore) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal BitCast");
  }
  
  BitCastInst::BitCastInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, BitCast, S, Name, InsertAtEnd) { 
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal BitCast");
  }
  
  AddrSpaceCastInst::AddrSpaceCastInst(
    Value *S, Type *Ty, const Twine &Name, Instruction *InsertBefore
  ) : CastInst(Ty, AddrSpaceCast, S, Name, InsertBefore) {
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal AddrSpaceCast");
  }
  
  AddrSpaceCastInst::AddrSpaceCastInst(
    Value *S, Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
  ) : CastInst(Ty, AddrSpaceCast, S, Name, InsertAtEnd) {
    assert(castIsValid(getOpcode(), S, Ty) && "Illegal AddrSpaceCast");
  }
  
  //===----------------------------------------------------------------------===//
  //                               CmpInst Classes
  //===----------------------------------------------------------------------===//
  
  void CmpInst::anchor() {}
  
  CmpInst::CmpInst(Type *ty, OtherOps op, unsigned short predicate,
                   Value *LHS, Value *RHS, const Twine &Name,
                   Instruction *InsertBefore)
    : Instruction(ty, op,
                  OperandTraits<CmpInst>::op_begin(this),
                  OperandTraits<CmpInst>::operands(this),
                  InsertBefore) {
      Op<0>() = LHS;
      Op<1>() = RHS;
    setPredicate((Predicate)predicate);
    setName(Name);
  }
  
  CmpInst::CmpInst(Type *ty, OtherOps op, unsigned short predicate,
                   Value *LHS, Value *RHS, const Twine &Name,
                   BasicBlock *InsertAtEnd)
    : Instruction(ty, op,
                  OperandTraits<CmpInst>::op_begin(this),
                  OperandTraits<CmpInst>::operands(this),
                  InsertAtEnd) {
    Op<0>() = LHS;
    Op<1>() = RHS;
    setPredicate((Predicate)predicate);
    setName(Name);
  }
  
  CmpInst *
  CmpInst::Create(OtherOps Op, unsigned short predicate,
                  Value *S1, Value *S2, 
                  const Twine &Name, Instruction *InsertBefore) {
    if (Op == Instruction::ICmp) {
      if (InsertBefore)
        return new ICmpInst(InsertBefore, CmpInst::Predicate(predicate),
                            S1, S2, Name);
      else
        return new ICmpInst(CmpInst::Predicate(predicate),
                            S1, S2, Name);
    }
    
    if (InsertBefore)
      return new FCmpInst(InsertBefore, CmpInst::Predicate(predicate),
                          S1, S2, Name);
    else
      return new FCmpInst(CmpInst::Predicate(predicate),
                          S1, S2, Name);
  }
  
  CmpInst *
  CmpInst::Create(OtherOps Op, unsigned short predicate, Value *S1, Value *S2, 
                  const Twine &Name, BasicBlock *InsertAtEnd) {
    if (Op == Instruction::ICmp) {
      return new ICmpInst(*InsertAtEnd, CmpInst::Predicate(predicate),
                          S1, S2, Name);
    }
    return new FCmpInst(*InsertAtEnd, CmpInst::Predicate(predicate),
                        S1, S2, Name);
  }
  
  void CmpInst::swapOperands() {
    if (ICmpInst *IC = dyn_cast<ICmpInst>(this))
      IC->swapOperands();
    else
      cast<FCmpInst>(this)->swapOperands();
  }
  
  bool CmpInst::isCommutative() const {
    if (const ICmpInst *IC = dyn_cast<ICmpInst>(this))
      return IC->isCommutative();
    return cast<FCmpInst>(this)->isCommutative();
  }
  
  bool CmpInst::isEquality() const {
    if (const ICmpInst *IC = dyn_cast<ICmpInst>(this))
      return IC->isEquality();
    return cast<FCmpInst>(this)->isEquality();
  }
  
  
  CmpInst::Predicate CmpInst::getInversePredicate(Predicate pred) {
    switch (pred) {
      default: llvm_unreachable("Unknown cmp predicate!");
      case ICMP_EQ: return ICMP_NE;
      case ICMP_NE: return ICMP_EQ;
      case ICMP_UGT: return ICMP_ULE;
      case ICMP_ULT: return ICMP_UGE;
      case ICMP_UGE: return ICMP_ULT;
      case ICMP_ULE: return ICMP_UGT;
      case ICMP_SGT: return ICMP_SLE;
      case ICMP_SLT: return ICMP_SGE;
      case ICMP_SGE: return ICMP_SLT;
      case ICMP_SLE: return ICMP_SGT;
  
      case FCMP_OEQ: return FCMP_UNE;
      case FCMP_ONE: return FCMP_UEQ;
      case FCMP_OGT: return FCMP_ULE;
      case FCMP_OLT: return FCMP_UGE;
      case FCMP_OGE: return FCMP_ULT;
      case FCMP_OLE: return FCMP_UGT;
      case FCMP_UEQ: return FCMP_ONE;
      case FCMP_UNE: return FCMP_OEQ;
      case FCMP_UGT: return FCMP_OLE;
      case FCMP_ULT: return FCMP_OGE;
      case FCMP_UGE: return FCMP_OLT;
      case FCMP_ULE: return FCMP_OGT;
      case FCMP_ORD: return FCMP_UNO;
      case FCMP_UNO: return FCMP_ORD;
      case FCMP_TRUE: return FCMP_FALSE;
      case FCMP_FALSE: return FCMP_TRUE;
    }
  }
  
  ICmpInst::Predicate ICmpInst::getSignedPredicate(Predicate pred) {
    switch (pred) {
      default: llvm_unreachable("Unknown icmp predicate!");
      case ICMP_EQ: case ICMP_NE: 
      case ICMP_SGT: case ICMP_SLT: case ICMP_SGE: case ICMP_SLE: 
         return pred;
      case ICMP_UGT: return ICMP_SGT;
      case ICMP_ULT: return ICMP_SLT;
      case ICMP_UGE: return ICMP_SGE;
      case ICMP_ULE: return ICMP_SLE;
    }
  }
  
  ICmpInst::Predicate ICmpInst::getUnsignedPredicate(Predicate pred) {
    switch (pred) {
      default: llvm_unreachable("Unknown icmp predicate!");
      case ICMP_EQ: case ICMP_NE: 
      case ICMP_UGT: case ICMP_ULT: case ICMP_UGE: case ICMP_ULE: 
         return pred;
      case ICMP_SGT: return ICMP_UGT;
      case ICMP_SLT: return ICMP_ULT;
      case ICMP_SGE: return ICMP_UGE;
      case ICMP_SLE: return ICMP_ULE;
    }
  }
  
  /// Initialize a set of values that all satisfy the condition with C.
  ///
  ConstantRange 
  ICmpInst::makeConstantRange(Predicate pred, const APInt &C) {
    APInt Lower(C);
    APInt Upper(C);
    uint32_t BitWidth = C.getBitWidth();
    switch (pred) {
    default: llvm_unreachable("Invalid ICmp opcode to ConstantRange ctor!");
    case ICmpInst::ICMP_EQ: ++Upper; break;
    case ICmpInst::ICMP_NE: ++Lower; break;
    case ICmpInst::ICMP_ULT:
      Lower = APInt::getMinValue(BitWidth);
      // Check for an empty-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/false);
      break;
    case ICmpInst::ICMP_SLT:
      Lower = APInt::getSignedMinValue(BitWidth);
      // Check for an empty-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/false);
      break;
    case ICmpInst::ICMP_UGT: 
      ++Lower; Upper = APInt::getMinValue(BitWidth);        // Min = Next(Max)
      // Check for an empty-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/false);
      break;
    case ICmpInst::ICMP_SGT:
      ++Lower; Upper = APInt::getSignedMinValue(BitWidth);  // Min = Next(Max)
      // Check for an empty-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/false);
      break;
    case ICmpInst::ICMP_ULE: 
      Lower = APInt::getMinValue(BitWidth); ++Upper; 
      // Check for a full-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/true);
      break;
    case ICmpInst::ICMP_SLE: 
      Lower = APInt::getSignedMinValue(BitWidth); ++Upper; 
      // Check for a full-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/true);
      break;
    case ICmpInst::ICMP_UGE:
      Upper = APInt::getMinValue(BitWidth);        // Min = Next(Max)
      // Check for a full-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/true);
      break;
    case ICmpInst::ICMP_SGE:
      Upper = APInt::getSignedMinValue(BitWidth);  // Min = Next(Max)
      // Check for a full-set condition.
      if (Lower == Upper)
        return ConstantRange(BitWidth, /*isFullSet=*/true);
      break;
    }
    return ConstantRange(Lower, Upper);
  }
  
  CmpInst::Predicate CmpInst::getSwappedPredicate(Predicate pred) {
    switch (pred) {
      default: llvm_unreachable("Unknown cmp predicate!");
      case ICMP_EQ: case ICMP_NE:
        return pred;
      case ICMP_SGT: return ICMP_SLT;
      case ICMP_SLT: return ICMP_SGT;
      case ICMP_SGE: return ICMP_SLE;
      case ICMP_SLE: return ICMP_SGE;
      case ICMP_UGT: return ICMP_ULT;
      case ICMP_ULT: return ICMP_UGT;
      case ICMP_UGE: return ICMP_ULE;
      case ICMP_ULE: return ICMP_UGE;
    
      case FCMP_FALSE: case FCMP_TRUE:
      case FCMP_OEQ: case FCMP_ONE:
      case FCMP_UEQ: case FCMP_UNE:
      case FCMP_ORD: case FCMP_UNO:
        return pred;
      case FCMP_OGT: return FCMP_OLT;
      case FCMP_OLT: return FCMP_OGT;
      case FCMP_OGE: return FCMP_OLE;
      case FCMP_OLE: return FCMP_OGE;
      case FCMP_UGT: return FCMP_ULT;
      case FCMP_ULT: return FCMP_UGT;
      case FCMP_UGE: return FCMP_ULE;
      case FCMP_ULE: return FCMP_UGE;
    }
  }
  
  bool CmpInst::isUnsigned(unsigned short predicate) {
    switch (predicate) {
      default: return false;
      case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_ULE: case ICmpInst::ICMP_UGT: 
      case ICmpInst::ICMP_UGE: return true;
    }
  }
  
  bool CmpInst::isSigned(unsigned short predicate) {
    switch (predicate) {
      default: return false;
      case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_SLE: case ICmpInst::ICMP_SGT: 
      case ICmpInst::ICMP_SGE: return true;
    }
  }
  
  bool CmpInst::isOrdered(unsigned short predicate) {
    switch (predicate) {
      default: return false;
      case FCmpInst::FCMP_OEQ: case FCmpInst::FCMP_ONE: case FCmpInst::FCMP_OGT: 
      case FCmpInst::FCMP_OLT: case FCmpInst::FCMP_OGE: case FCmpInst::FCMP_OLE: 
      case FCmpInst::FCMP_ORD: return true;
    }
  }
        
  bool CmpInst::isUnordered(unsigned short predicate) {
    switch (predicate) {
      default: return false;
      case FCmpInst::FCMP_UEQ: case FCmpInst::FCMP_UNE: case FCmpInst::FCMP_UGT: 
      case FCmpInst::FCMP_ULT: case FCmpInst::FCMP_UGE: case FCmpInst::FCMP_ULE: 
      case FCmpInst::FCMP_UNO: return true;
    }
  }
  
  bool CmpInst::isTrueWhenEqual(unsigned short predicate) {
    switch(predicate) {
      default: return false;
      case ICMP_EQ:   case ICMP_UGE: case ICMP_ULE: case ICMP_SGE: case ICMP_SLE:
      case FCMP_TRUE: case FCMP_UEQ: case FCMP_UGE: case FCMP_ULE: return true;
    }
  }
  
  bool CmpInst::isFalseWhenEqual(unsigned short predicate) {
    switch(predicate) {
    case ICMP_NE:    case ICMP_UGT: case ICMP_ULT: case ICMP_SGT: case ICMP_SLT:
    case FCMP_FALSE: case FCMP_ONE: case FCMP_OGT: case FCMP_OLT: return true;
    default: return false;
    }
  }
  
  
  //===----------------------------------------------------------------------===//
  //                        SwitchInst Implementation
  //===----------------------------------------------------------------------===//
  
  void SwitchInst::init(Value *Value, BasicBlock *Default, unsigned NumReserved) {
    assert(Value && Default && NumReserved);
    ReservedSpace = NumReserved;
    setNumHungOffUseOperands(2);
    allocHungoffUses(ReservedSpace);
  
    Op<0>() = Value;
    Op<1>() = Default;
  }
  
  /// SwitchInst ctor - Create a new switch instruction, specifying a value to
  /// switch on and a default destination.  The number of additional cases can
  /// be specified here to make memory allocation more efficient.  This
  /// constructor can also autoinsert before another instruction.
  SwitchInst::SwitchInst(Value *Value, BasicBlock *Default, unsigned NumCases,
                         Instruction *InsertBefore)
    : TerminatorInst(Type::getVoidTy(Value->getContext()), Instruction::Switch,
                     nullptr, 0, InsertBefore) {
    init(Value, Default, 2+NumCases*2);
  }
  
  /// SwitchInst ctor - Create a new switch instruction, specifying a value to
  /// switch on and a default destination.  The number of additional cases can
  /// be specified here to make memory allocation more efficient.  This
  /// constructor also autoinserts at the end of the specified BasicBlock.
  SwitchInst::SwitchInst(Value *Value, BasicBlock *Default, unsigned NumCases,
                         BasicBlock *InsertAtEnd)
    : TerminatorInst(Type::getVoidTy(Value->getContext()), Instruction::Switch,
                     nullptr, 0, InsertAtEnd) {
    init(Value, Default, 2+NumCases*2);
  }
  
  SwitchInst::SwitchInst(const SwitchInst &SI)
    : TerminatorInst(SI.getType(), Instruction::Switch, nullptr, 0) {
    init(SI.getCondition(), SI.getDefaultDest(), SI.getNumOperands());
    setNumHungOffUseOperands(SI.getNumOperands());
    Use *OL = getOperandList();
    const Use *InOL = SI.getOperandList();
    for (unsigned i = 2, E = SI.getNumOperands(); i != E; i += 2) {
      OL[i] = InOL[i];
      OL[i+1] = InOL[i+1];
    }
    SubclassOptionalData = SI.SubclassOptionalData;
  }
  
  
  /// addCase - Add an entry to the switch instruction...
  ///
  void SwitchInst::addCase(ConstantInt *OnVal, BasicBlock *Dest) {
    unsigned NewCaseIdx = getNumCases();
    unsigned OpNo = getNumOperands();
    if (OpNo+2 > ReservedSpace)
      growOperands();  // Get more space!
    // Initialize some new operands.
    assert(OpNo+1 < ReservedSpace && "Growing didn't work!");
    setNumHungOffUseOperands(OpNo+2);
    CaseIt Case(this, NewCaseIdx);
    Case.setValue(OnVal);
    Case.setSuccessor(Dest);
  }
  
  /// removeCase - This method removes the specified case and its successor
  /// from the switch instruction.
  void SwitchInst::removeCase(CaseIt i) {
    unsigned idx = i.getCaseIndex();
    
    assert(2 + idx*2 < getNumOperands() && "Case index out of range!!!");
  
    unsigned NumOps = getNumOperands();
    Use *OL = getOperandList();
  
    // Overwrite this case with the end of the list.
    if (2 + (idx + 1) * 2 != NumOps) {
      OL[2 + idx * 2] = OL[NumOps - 2];
      OL[2 + idx * 2 + 1] = OL[NumOps - 1];
    }
  
    // Nuke the last value.
    OL[NumOps-2].set(nullptr);
    OL[NumOps-2+1].set(nullptr);
    setNumHungOffUseOperands(NumOps-2);
  }
  
  /// growOperands - grow operands - This grows the operand list in response
  /// to a push_back style of operation.  This grows the number of ops by 3 times.
  ///
  void SwitchInst::growOperands() {
    unsigned e = getNumOperands();
    unsigned NumOps = e*3;
  
    ReservedSpace = NumOps;
    growHungoffUses(ReservedSpace);
  }
  
  
  BasicBlock *SwitchInst::getSuccessorV(unsigned idx) const {
    return getSuccessor(idx);
  }
  unsigned SwitchInst::getNumSuccessorsV() const {
    return getNumSuccessors();
  }
  void SwitchInst::setSuccessorV(unsigned idx, BasicBlock *B) {
    setSuccessor(idx, B);
  }
  
  //===----------------------------------------------------------------------===//
  //                        IndirectBrInst Implementation
  //===----------------------------------------------------------------------===//
  
  void IndirectBrInst::init(Value *Address, unsigned NumDests) {
    assert(Address && Address->getType()->isPointerTy() &&
           "Address of indirectbr must be a pointer");
    ReservedSpace = 1+NumDests;
    setNumHungOffUseOperands(1);
    allocHungoffUses(ReservedSpace);
  
    Op<0>() = Address;
  }
  
  
  /// growOperands - grow operands - This grows the operand list in response
  /// to a push_back style of operation.  This grows the number of ops by 2 times.
  ///
  void IndirectBrInst::growOperands() {
    unsigned e = getNumOperands();
    unsigned NumOps = e*2;
    
    ReservedSpace = NumOps;
    growHungoffUses(ReservedSpace);
  }
  
  IndirectBrInst::IndirectBrInst(Value *Address, unsigned NumCases,
                                 Instruction *InsertBefore)
  : TerminatorInst(Type::getVoidTy(Address->getContext()),Instruction::IndirectBr,
                   nullptr, 0, InsertBefore) {
    init(Address, NumCases);
  }
  
  IndirectBrInst::IndirectBrInst(Value *Address, unsigned NumCases,
                                 BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::getVoidTy(Address->getContext()),Instruction::IndirectBr,
                   nullptr, 0, InsertAtEnd) {
    init(Address, NumCases);
  }
  
  IndirectBrInst::IndirectBrInst(const IndirectBrInst &IBI)
      : TerminatorInst(Type::getVoidTy(IBI.getContext()), Instruction::IndirectBr,
                       nullptr, IBI.getNumOperands()) {
    allocHungoffUses(IBI.getNumOperands());
    Use *OL = getOperandList();
    const Use *InOL = IBI.getOperandList();
    for (unsigned i = 0, E = IBI.getNumOperands(); i != E; ++i)
      OL[i] = InOL[i];
    SubclassOptionalData = IBI.SubclassOptionalData;
  }
  
  /// addDestination - Add a destination.
  ///
  void IndirectBrInst::addDestination(BasicBlock *DestBB) {
    unsigned OpNo = getNumOperands();
    if (OpNo+1 > ReservedSpace)
      growOperands();  // Get more space!
    // Initialize some new operands.
    assert(OpNo < ReservedSpace && "Growing didn't work!");
    setNumHungOffUseOperands(OpNo+1);
    getOperandList()[OpNo] = DestBB;
  }
  
  /// removeDestination - This method removes the specified successor from the
  /// indirectbr instruction.
  void IndirectBrInst::removeDestination(unsigned idx) {
    assert(idx < getNumOperands()-1 && "Successor index out of range!");
    
    unsigned NumOps = getNumOperands();
    Use *OL = getOperandList();
  
    // Replace this value with the last one.
    OL[idx+1] = OL[NumOps-1];
    
    // Nuke the last value.
    OL[NumOps-1].set(nullptr);
    setNumHungOffUseOperands(NumOps-1);
  }
  
  BasicBlock *IndirectBrInst::getSuccessorV(unsigned idx) const {
    return getSuccessor(idx);
  }
  unsigned IndirectBrInst::getNumSuccessorsV() const {
    return getNumSuccessors();
  }
  void IndirectBrInst::setSuccessorV(unsigned idx, BasicBlock *B) {
    setSuccessor(idx, B);
  }
  
  //===----------------------------------------------------------------------===//
  //                           clone_impl() implementations
  //===----------------------------------------------------------------------===//
  
  // Define these methods here so vtables don't get emitted into every translation
  // unit that uses these classes.
  
  GetElementPtrInst *GetElementPtrInst::clone_impl() const {
    return new (getNumOperands()) GetElementPtrInst(*this);
  }
  
  BinaryOperator *BinaryOperator::clone_impl() const {
    return Create(getOpcode(), Op<0>(), Op<1>());
  }
  
  FCmpInst* FCmpInst::clone_impl() const {
    return new FCmpInst(getPredicate(), Op<0>(), Op<1>());
  }
  
  ICmpInst* ICmpInst::clone_impl() const {
    return new ICmpInst(getPredicate(), Op<0>(), Op<1>());
  }
  
  ExtractValueInst *ExtractValueInst::clone_impl() const {
    return new ExtractValueInst(*this);
  }
  
  InsertValueInst *InsertValueInst::clone_impl() const {
    return new InsertValueInst(*this);
  }
  
  AllocaInst *AllocaInst::clone_impl() const {
    AllocaInst *Result = new AllocaInst(getAllocatedType(),
                                        (Value *)getOperand(0), getAlignment());
    Result->setUsedWithInAlloca(isUsedWithInAlloca());
    return Result;
  }
  
  LoadInst *LoadInst::clone_impl() const {
    return new LoadInst(getOperand(0), Twine(), isVolatile(),
                        getAlignment(), getOrdering(), getSynchScope());
  }
  
  StoreInst *StoreInst::clone_impl() const {
    return new StoreInst(getOperand(0), getOperand(1), isVolatile(),
                         getAlignment(), getOrdering(), getSynchScope());
    
  }
  
  AtomicCmpXchgInst *AtomicCmpXchgInst::clone_impl() const {
    AtomicCmpXchgInst *Result =
      new AtomicCmpXchgInst(getOperand(0), getOperand(1), getOperand(2),
                            getSuccessOrdering(), getFailureOrdering(),
                            getSynchScope());
    Result->setVolatile(isVolatile());
    Result->setWeak(isWeak());
    return Result;
  }
  
  AtomicRMWInst *AtomicRMWInst::clone_impl() const {
    AtomicRMWInst *Result =
      new AtomicRMWInst(getOperation(),getOperand(0), getOperand(1),
                        getOrdering(), getSynchScope());
    Result->setVolatile(isVolatile());
    return Result;
  }
  
  FenceInst *FenceInst::clone_impl() const {
    return new FenceInst(getContext(), getOrdering(), getSynchScope());
  }
  
  TruncInst *TruncInst::clone_impl() const {
    return new TruncInst(getOperand(0), getType());
  }
  
  ZExtInst *ZExtInst::clone_impl() const {
    return new ZExtInst(getOperand(0), getType());
  }
  
  SExtInst *SExtInst::clone_impl() const {
    return new SExtInst(getOperand(0), getType());
  }
  
  FPTruncInst *FPTruncInst::clone_impl() const {
    return new FPTruncInst(getOperand(0), getType());
  }
  
  FPExtInst *FPExtInst::clone_impl() const {
    return new FPExtInst(getOperand(0), getType());
  }
  
  UIToFPInst *UIToFPInst::clone_impl() const {
    return new UIToFPInst(getOperand(0), getType());
  }
  
  SIToFPInst *SIToFPInst::clone_impl() const {
    return new SIToFPInst(getOperand(0), getType());
  }
  
  FPToUIInst *FPToUIInst::clone_impl() const {
    return new FPToUIInst(getOperand(0), getType());
  }
  
  FPToSIInst *FPToSIInst::clone_impl() const {
    return new FPToSIInst(getOperand(0), getType());
  }
  
  PtrToIntInst *PtrToIntInst::clone_impl() const {
    return new PtrToIntInst(getOperand(0), getType());
  }
  
  IntToPtrInst *IntToPtrInst::clone_impl() const {
    return new IntToPtrInst(getOperand(0), getType());
  }
  
  BitCastInst *BitCastInst::clone_impl() const {
    return new BitCastInst(getOperand(0), getType());
  }
  
  AddrSpaceCastInst *AddrSpaceCastInst::clone_impl() const {
    return new AddrSpaceCastInst(getOperand(0), getType());
  }
  
  CallInst *CallInst::clone_impl() const {
    return  new(getNumOperands()) CallInst(*this);
  }
  
  SelectInst *SelectInst::clone_impl() const {
    return SelectInst::Create(getOperand(0), getOperand(1), getOperand(2));
  }
  
  VAArgInst *VAArgInst::clone_impl() const {
    return new VAArgInst(getOperand(0), getType());
  }
  
  ExtractElementInst *ExtractElementInst::clone_impl() const {
    return ExtractElementInst::Create(getOperand(0), getOperand(1));
  }
  
  InsertElementInst *InsertElementInst::clone_impl() const {
    return InsertElementInst::Create(getOperand(0), getOperand(1), getOperand(2));
  }
  
  ShuffleVectorInst *ShuffleVectorInst::clone_impl() const {
    return new ShuffleVectorInst(getOperand(0), getOperand(1), getOperand(2));
  }
  
  PHINode *PHINode::clone_impl() const {
    return new PHINode(*this);
  }
  
  LandingPadInst *LandingPadInst::clone_impl() const {
    return new LandingPadInst(*this);
  }
  
  ReturnInst *ReturnInst::clone_impl() const {
    return new(getNumOperands()) ReturnInst(*this);
  }
  
  BranchInst *BranchInst::clone_impl() const {
    return new(getNumOperands()) BranchInst(*this);
  }
  
  SwitchInst *SwitchInst::clone_impl() const {
    return new SwitchInst(*this);
  }
  
  IndirectBrInst *IndirectBrInst::clone_impl() const {
    return new IndirectBrInst(*this);
  }
  
  
  InvokeInst *InvokeInst::clone_impl() const {
    return new(getNumOperands()) InvokeInst(*this);
  }
  
  ResumeInst *ResumeInst::clone_impl() const {
    return new(1) ResumeInst(*this);
  }
  
  UnreachableInst *UnreachableInst::clone_impl() const {
    LLVMContext &Context = getContext();
    return new UnreachableInst(Context);
  }
  