lib/CodeGen/IntrinsicLowering.cpp - llvm - Git at Google

 //===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file was developed by the LLVM research group and is distributed under
 // the University of Illinois Open Source License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the default intrinsic lowering implementation.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/CodeGen/IntrinsicLowering.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Module.h"
 #include "llvm/Instructions.h"
 #include "llvm/Type.h"
 #include <iostream>

 using namespace llvm;

 template <class ArgIt>
 static Function *EnsureFunctionExists(Module &M, const char *Name,
                                       ArgIt ArgBegin, ArgIt ArgEnd,
                                       const Type *RetTy) {
   if (Function *F = M.getNamedFunction(Name)) return F;
   // It doesn't already exist in the program, insert a new definition now.
   std::vector<const Type *> ParamTys;
   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
     ParamTys.push_back(I->getType());
   return M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
 }

 /// ReplaceCallWith - This function is used when we want to lower an intrinsic
 /// call to a call of an external function.  This handles hard cases such as
 /// when there was already a prototype for the external function, and if that
 /// prototype doesn't match the arguments we expect to pass in.
 template <class ArgIt>
 static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
                                  ArgIt ArgBegin, ArgIt ArgEnd,
                                  const Type *RetTy, Function *&FCache) {
   if (!FCache) {
     // If we haven't already looked up this function, check to see if the
     // program already contains a function with this name.
     Module *M = CI->getParent()->getParent()->getParent();
     FCache = M->getNamedFunction(NewFn);
     if (!FCache) {
       // It doesn't already exist in the program, insert a new definition now.
       std::vector<const Type *> ParamTys;
       for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
         ParamTys.push_back((*I)->getType());
       FCache = M->getOrInsertFunction(NewFn,
                                      FunctionType::get(RetTy, ParamTys, false));
     }
    }

   const FunctionType *FT = FCache->getFunctionType();
   std::vector<Value*> Operands;
   unsigned ArgNo = 0;
   for (ArgIt I = ArgBegin; I != ArgEnd && ArgNo != FT->getNumParams();
        ++I, ++ArgNo) {
     Value *Arg = *I;
     if (Arg->getType() != FT->getParamType(ArgNo))
       Arg = new CastInst(Arg, FT->getParamType(ArgNo), Arg->getName(), CI);
     Operands.push_back(Arg);
   }
   // Pass nulls into any additional arguments...
   for (; ArgNo != FT->getNumParams(); ++ArgNo)
     Operands.push_back(Constant::getNullValue(FT->getParamType(ArgNo)));

   std::string Name = CI->getName(); CI->setName("");
   if (FT->getReturnType() == Type::VoidTy) Name.clear();
   CallInst *NewCI = new CallInst(FCache, Operands, Name, CI);
   if (!CI->use_empty()) {
     Value *V = NewCI;
     if (CI->getType() != NewCI->getType())
       V = new CastInst(NewCI, CI->getType(), Name, CI);
     CI->replaceAllUsesWith(V);
   }
   return NewCI;
 }

 void DefaultIntrinsicLowering::AddPrototypes(Module &M) {
   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
     if (I->isExternal() && !I->use_empty())
       switch (I->getIntrinsicID()) {
       default: break;
       case Intrinsic::setjmp:
         EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(),
                              Type::IntTy);
         break;
       case Intrinsic::longjmp:
         EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(),
                              Type::VoidTy);
         break;
       case Intrinsic::siglongjmp:
         EnsureFunctionExists(M, "abort", I->arg_end(), I->arg_end(),
                              Type::VoidTy);
         break;
       case Intrinsic::memcpy:
         EnsureFunctionExists(M, "memcpy", I->arg_begin(), --I->arg_end(),
                              I->arg_begin()->getType());
         break;
       case Intrinsic::memmove:
         EnsureFunctionExists(M, "memmove", I->arg_begin(), --I->arg_end(),
                              I->arg_begin()->getType());
         break;
       case Intrinsic::memset:
         M.getOrInsertFunction("memset", PointerType::get(Type::SByteTy),
                               PointerType::get(Type::SByteTy),
                               Type::IntTy, (--(--I->arg_end()))->getType(),
                               (Type *)0);
         break;
       case Intrinsic::isunordered:
         EnsureFunctionExists(M, "isunordered", I->arg_begin(), I->arg_end(),
                              Type::BoolTy);
         break;
       case Intrinsic::sqrt:
         if(I->arg_begin()->getType() == Type::FloatTy)
           EnsureFunctionExists(M, "sqrtf", I->arg_begin(), I->arg_end(),
                                Type::FloatTy);
         else
           EnsureFunctionExists(M, "sqrt", I->arg_begin(), I->arg_end(),
                                Type::DoubleTy);
         break;
       }
 }

 /// LowerCTPOP - Emit the code to lower ctpop of V before the specified
 /// instruction.
 static Value *LowerCTPOP(Value *V, Instruction *IP) {
   assert(V->getType()->isInteger() && "Can't ctpop a non-integer type!");

   static const uint64_t MaskValues[6] = {
     0x5555555555555555ULL, 0x3333333333333333ULL,
     0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
     0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
   };

   const Type *DestTy = V->getType();

   // Force to unsigned so that the shift rights are logical.
   if (DestTy->isSigned())
     V = new CastInst(V, DestTy->getUnsignedVersion(), V->getName(), IP);

   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
   for (unsigned i = 1, ct = 0; i != BitSize; i <<= 1, ++ct) {
     Value *MaskCst =
       ConstantExpr::getCast(ConstantUInt::get(Type::ULongTy,
                                               MaskValues[ct]), V->getType());
     Value *LHS = BinaryOperator::createAnd(V, MaskCst, "cppop.and1", IP);
     Value *VShift = new ShiftInst(Instruction::Shr, V,
                       ConstantInt::get(Type::UByteTy, i), "ctpop.sh", IP);
     Value *RHS = BinaryOperator::createAnd(VShift, MaskCst, "cppop.and2", IP);
     V = BinaryOperator::createAdd(LHS, RHS, "ctpop.step", IP);
   }

   if (V->getType() != DestTy)
     V = new CastInst(V, DestTy, V->getName(), IP);
   return V;
 }

 /// LowerCTLZ - Emit the code to lower ctlz of V before the specified
 /// instruction.
 static Value *LowerCTLZ(Value *V, Instruction *IP) {
   const Type *DestTy = V->getType();

   // Force to unsigned so that the shift rights are logical.
   if (DestTy->isSigned())
     V = new CastInst(V, DestTy->getUnsignedVersion(), V->getName(), IP);

   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
   for (unsigned i = 1; i != BitSize; i <<= 1) {
     Value *ShVal = ConstantInt::get(Type::UByteTy, i);
     ShVal = new ShiftInst(Instruction::Shr, V, ShVal, "ctlz.sh", IP);
     V = BinaryOperator::createOr(V, ShVal, "ctlz.step", IP);
   }

   if (V->getType() != DestTy)
     V = new CastInst(V, DestTy, V->getName(), IP);

   V = BinaryOperator::createNot(V, "", IP);
   return LowerCTPOP(V, IP);
 }

 void DefaultIntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
   Function *Callee = CI->getCalledFunction();
   assert(Callee && "Cannot lower an indirect call!");

   switch (Callee->getIntrinsicID()) {
   case Intrinsic::not_intrinsic:
     std::cerr << "Cannot lower a call to a non-intrinsic function '"
               << Callee->getName() << "'!\n";
     abort();
   default:
     std::cerr << "Error: Code generator does not support intrinsic function '"
               << Callee->getName() << "'!\n";
     abort();

     // The setjmp/longjmp intrinsics should only exist in the code if it was
     // never optimized (ie, right out of the CFE), or if it has been hacked on
     // by the lowerinvoke pass.  In both cases, the right thing to do is to
     // convert the call to an explicit setjmp or longjmp call.
   case Intrinsic::setjmp: {
     static Function *SetjmpFCache = 0;
     Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(),
                                Type::IntTy, SetjmpFCache);
     if (CI->getType() != Type::VoidTy)
       CI->replaceAllUsesWith(V);
     break;
   }
   case Intrinsic::sigsetjmp:
      if (CI->getType() != Type::VoidTy)
        CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
      break;

   case Intrinsic::longjmp: {
     static Function *LongjmpFCache = 0;
     ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(),
                     Type::VoidTy, LongjmpFCache);
     break;
   }

   case Intrinsic::siglongjmp: {
     // Insert the call to abort
     static Function *AbortFCache = 0;
     ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(), Type::VoidTy,
                     AbortFCache);
     break;
   }
   case Intrinsic::ctpop:
     CI->replaceAllUsesWith(LowerCTPOP(CI->getOperand(1), CI));
     break;

   case Intrinsic::ctlz:
     CI->replaceAllUsesWith(LowerCTLZ(CI->getOperand(1), CI));
     break;
   case Intrinsic::cttz: {
     // cttz(x) -> ctpop(~X & (X-1))
     Value *Src = CI->getOperand(1);
     Value *NotSrc = BinaryOperator::createNot(Src, Src->getName()+".not", CI);
     Value *SrcM1  = ConstantInt::get(Src->getType(), 1);
     SrcM1 = BinaryOperator::createSub(Src, SrcM1, "", CI);
     Src = LowerCTPOP(BinaryOperator::createAnd(NotSrc, SrcM1, "", CI), CI);
     CI->replaceAllUsesWith(Src);
     break;
   }

   case Intrinsic::returnaddress:
   case Intrinsic::frameaddress:
     std::cerr << "WARNING: this target does not support the llvm."
               << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
                   "return" : "frame") << "address intrinsic.\n";
     CI->replaceAllUsesWith(ConstantPointerNull::get(
                                             cast<PointerType>(CI->getType())));
     break;

   case Intrinsic::prefetch:
     break;    // Simply strip out prefetches on unsupported architectures

   case Intrinsic::pcmarker:
     break;    // Simply strip out pcmarker on unsupported architectures

   case Intrinsic::dbg_stoppoint:
   case Intrinsic::dbg_region_start:
   case Intrinsic::dbg_region_end:
   case Intrinsic::dbg_declare:
   case Intrinsic::dbg_func_start:
     if (CI->getType() != Type::VoidTy)
       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
     break;    // Simply strip out debugging intrinsics

   case Intrinsic::memcpy: {
     // The memcpy intrinsic take an extra alignment argument that the memcpy
     // libc function does not.
     static Function *MemcpyFCache = 0;
     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
                     (*(CI->op_begin()+1))->getType(), MemcpyFCache);
     break;
   }
   case Intrinsic::memmove: {
     // The memmove intrinsic take an extra alignment argument that the memmove
     // libc function does not.
     static Function *MemmoveFCache = 0;
     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
                     (*(CI->op_begin()+1))->getType(), MemmoveFCache);
     break;
   }
   case Intrinsic::memset: {
     // The memset intrinsic take an extra alignment argument that the memset
     // libc function does not.
     static Function *MemsetFCache = 0;
     ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
                     (*(CI->op_begin()+1))->getType(), MemsetFCache);
     break;
   }
   case Intrinsic::isunordered: {
     Value *L = CI->getOperand(1);
     Value *R = CI->getOperand(2);

     Value *LIsNan = new SetCondInst(Instruction::SetNE, L, L, "LIsNan", CI);
     Value *RIsNan = new SetCondInst(Instruction::SetNE, R, R, "RIsNan", CI);
     CI->replaceAllUsesWith(
       BinaryOperator::create(Instruction::Or, LIsNan, RIsNan,
                              "isunordered", CI));
     break;
   }
   case Intrinsic::sqrt: {
     static Function *sqrtFCache = 0;
     static Function *sqrtfFCache = 0;
     if(CI->getType() == Type::FloatTy)
       ReplaceCallWith("sqrtf", CI, CI->op_begin()+1, CI->op_end(),
                       Type::FloatTy, sqrtfFCache);
     else
       ReplaceCallWith("sqrt", CI, CI->op_begin()+1, CI->op_end(),
                       Type::DoubleTy, sqrtFCache);
     break;
   }
   }

   assert(CI->use_empty() &&
          "Lowering should have eliminated any uses of the intrinsic call!");
   CI->eraseFromParent();
 }
	//===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file was developed by the LLVM research group and is distributed under
	// the University of Illinois Open Source License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements the default intrinsic lowering implementation.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/CodeGen/IntrinsicLowering.h"
	#include "llvm/Constants.h"
	#include "llvm/DerivedTypes.h"
	#include "llvm/Module.h"
	#include "llvm/Instructions.h"
	#include "llvm/Type.h"
	#include <iostream>

	using namespace llvm;

	template <class ArgIt>
	static Function EnsureFunctionExists(Module &M, const char Name,
	ArgIt ArgBegin, ArgIt ArgEnd,
	const Type *RetTy) {
	if (Function *F = M.getNamedFunction(Name)) return F;
	// It doesn't already exist in the program, insert a new definition now.
	std::vector<const Type *> ParamTys;
	for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
	ParamTys.push_back(I->getType());
	return M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
	}

	/// ReplaceCallWith - This function is used when we want to lower an intrinsic
	/// call to a call of an external function. This handles hard cases such as
	/// when there was already a prototype for the external function, and if that
	/// prototype doesn't match the arguments we expect to pass in.
	template <class ArgIt>
	static CallInst ReplaceCallWith(const char NewFn, CallInst *CI,
	ArgIt ArgBegin, ArgIt ArgEnd,
	const Type RetTy, Function &FCache) {
	if (!FCache) {
	// If we haven't already looked up this function, check to see if the
	// program already contains a function with this name.
	Module *M = CI->getParent()->getParent()->getParent();
	FCache = M->getNamedFunction(NewFn);
	if (!FCache) {
	// It doesn't already exist in the program, insert a new definition now.
	std::vector<const Type *> ParamTys;
	for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
	ParamTys.push_back((*I)->getType());
	FCache = M->getOrInsertFunction(NewFn,
	FunctionType::get(RetTy, ParamTys, false));
	}
	}

	const FunctionType *FT = FCache->getFunctionType();
	std::vector<Value*> Operands;
	unsigned ArgNo = 0;
	for (ArgIt I = ArgBegin; I != ArgEnd && ArgNo != FT->getNumParams();
	++I, ++ArgNo) {
	Value Arg = I;
	if (Arg->getType() != FT->getParamType(ArgNo))
	Arg = new CastInst(Arg, FT->getParamType(ArgNo), Arg->getName(), CI);
	Operands.push_back(Arg);
	}
	// Pass nulls into any additional arguments...
	for (; ArgNo != FT->getNumParams(); ++ArgNo)
	Operands.push_back(Constant::getNullValue(FT->getParamType(ArgNo)));

	std::string Name = CI->getName(); CI->setName("");
	if (FT->getReturnType() == Type::VoidTy) Name.clear();
	CallInst *NewCI = new CallInst(FCache, Operands, Name, CI);
	if (!CI->use_empty()) {
	Value *V = NewCI;
	if (CI->getType() != NewCI->getType())
	V = new CastInst(NewCI, CI->getType(), Name, CI);
	CI->replaceAllUsesWith(V);
	}
	return NewCI;
	}

	void DefaultIntrinsicLowering::AddPrototypes(Module &M) {
	for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
	if (I->isExternal() && !I->use_empty())
	switch (I->getIntrinsicID()) {
	default: break;
	case Intrinsic::setjmp:
	EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(),
	Type::IntTy);
	break;
	case Intrinsic::longjmp:
	EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(),
	Type::VoidTy);
	break;
	case Intrinsic::siglongjmp:
	EnsureFunctionExists(M, "abort", I->arg_end(), I->arg_end(),
	Type::VoidTy);
	break;
	case Intrinsic::memcpy:
	EnsureFunctionExists(M, "memcpy", I->arg_begin(), --I->arg_end(),
	I->arg_begin()->getType());
	break;
	case Intrinsic::memmove:
	EnsureFunctionExists(M, "memmove", I->arg_begin(), --I->arg_end(),
	I->arg_begin()->getType());
	break;
	case Intrinsic::memset:
	M.getOrInsertFunction("memset", PointerType::get(Type::SByteTy),
	PointerType::get(Type::SByteTy),
	Type::IntTy, (--(--I->arg_end()))->getType(),
	(Type *)0);
	break;
	case Intrinsic::isunordered:
	EnsureFunctionExists(M, "isunordered", I->arg_begin(), I->arg_end(),
	Type::BoolTy);
	break;
	case Intrinsic::sqrt:
	if(I->arg_begin()->getType() == Type::FloatTy)
	EnsureFunctionExists(M, "sqrtf", I->arg_begin(), I->arg_end(),
	Type::FloatTy);
	else
	EnsureFunctionExists(M, "sqrt", I->arg_begin(), I->arg_end(),
	Type::DoubleTy);
	break;
	}
	}

	/// LowerCTPOP - Emit the code to lower ctpop of V before the specified
	/// instruction.
	static Value LowerCTPOP(Value V, Instruction *IP) {
	assert(V->getType()->isInteger() && "Can't ctpop a non-integer type!");

	static const uint64_t MaskValues[6] = {
	0x5555555555555555ULL, 0x3333333333333333ULL,
	0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
	0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
	};

	const Type *DestTy = V->getType();

	// Force to unsigned so that the shift rights are logical.
	if (DestTy->isSigned())
	V = new CastInst(V, DestTy->getUnsignedVersion(), V->getName(), IP);

	unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
	for (unsigned i = 1, ct = 0; i != BitSize; i <<= 1, ++ct) {
	Value *MaskCst =
	ConstantExpr::getCast(ConstantUInt::get(Type::ULongTy,
	MaskValues[ct]), V->getType());
	Value *LHS = BinaryOperator::createAnd(V, MaskCst, "cppop.and1", IP);
	Value *VShift = new ShiftInst(Instruction::Shr, V,
	ConstantInt::get(Type::UByteTy, i), "ctpop.sh", IP);
	Value *RHS = BinaryOperator::createAnd(VShift, MaskCst, "cppop.and2", IP);
	V = BinaryOperator::createAdd(LHS, RHS, "ctpop.step", IP);
	}

	if (V->getType() != DestTy)
	V = new CastInst(V, DestTy, V->getName(), IP);
	return V;
	}

	/// LowerCTLZ - Emit the code to lower ctlz of V before the specified
	/// instruction.
	static Value LowerCTLZ(Value V, Instruction *IP) {
	const Type *DestTy = V->getType();

	// Force to unsigned so that the shift rights are logical.
	if (DestTy->isSigned())
	V = new CastInst(V, DestTy->getUnsignedVersion(), V->getName(), IP);

	unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
	for (unsigned i = 1; i != BitSize; i <<= 1) {
	Value *ShVal = ConstantInt::get(Type::UByteTy, i);
	ShVal = new ShiftInst(Instruction::Shr, V, ShVal, "ctlz.sh", IP);
	V = BinaryOperator::createOr(V, ShVal, "ctlz.step", IP);
	}

	if (V->getType() != DestTy)
	V = new CastInst(V, DestTy, V->getName(), IP);

	V = BinaryOperator::createNot(V, "", IP);
	return LowerCTPOP(V, IP);
	}

	void DefaultIntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
	Function *Callee = CI->getCalledFunction();
	assert(Callee && "Cannot lower an indirect call!");

	switch (Callee->getIntrinsicID()) {
	case Intrinsic::not_intrinsic:
	std::cerr << "Cannot lower a call to a non-intrinsic function '"
	<< Callee->getName() << "'!\n";
	abort();
	default:
	std::cerr << "Error: Code generator does not support intrinsic function '"
	<< Callee->getName() << "'!\n";
	abort();

	// The setjmp/longjmp intrinsics should only exist in the code if it was
	// never optimized (ie, right out of the CFE), or if it has been hacked on
	// by the lowerinvoke pass. In both cases, the right thing to do is to
	// convert the call to an explicit setjmp or longjmp call.
	case Intrinsic::setjmp: {
	static Function *SetjmpFCache = 0;
	Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(),
	Type::IntTy, SetjmpFCache);
	if (CI->getType() != Type::VoidTy)
	CI->replaceAllUsesWith(V);
	break;
	}
	case Intrinsic::sigsetjmp:
	if (CI->getType() != Type::VoidTy)
	CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
	break;

	case Intrinsic::longjmp: {
	static Function *LongjmpFCache = 0;
	ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(),
	Type::VoidTy, LongjmpFCache);
	break;
	}

	case Intrinsic::siglongjmp: {
	// Insert the call to abort
	static Function *AbortFCache = 0;
	ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(), Type::VoidTy,
	AbortFCache);
	break;
	}
	case Intrinsic::ctpop:
	CI->replaceAllUsesWith(LowerCTPOP(CI->getOperand(1), CI));
	break;

	case Intrinsic::ctlz:
	CI->replaceAllUsesWith(LowerCTLZ(CI->getOperand(1), CI));
	break;
	case Intrinsic::cttz: {
	// cttz(x) -> ctpop(~X & (X-1))
	Value *Src = CI->getOperand(1);
	Value *NotSrc = BinaryOperator::createNot(Src, Src->getName()+".not", CI);
	Value *SrcM1 = ConstantInt::get(Src->getType(), 1);
	SrcM1 = BinaryOperator::createSub(Src, SrcM1, "", CI);
	Src = LowerCTPOP(BinaryOperator::createAnd(NotSrc, SrcM1, "", CI), CI);
	CI->replaceAllUsesWith(Src);
	break;
	}

	case Intrinsic::returnaddress:
	case Intrinsic::frameaddress:
	std::cerr << "WARNING: this target does not support the llvm."
	<< (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
	"return" : "frame") << "address intrinsic.\n";
	CI->replaceAllUsesWith(ConstantPointerNull::get(
	cast<PointerType>(CI->getType())));
	break;

	case Intrinsic::prefetch:
	break; // Simply strip out prefetches on unsupported architectures

	case Intrinsic::pcmarker:
	break; // Simply strip out pcmarker on unsupported architectures

	case Intrinsic::dbg_stoppoint:
	case Intrinsic::dbg_region_start:
	case Intrinsic::dbg_region_end:
	case Intrinsic::dbg_declare:
	case Intrinsic::dbg_func_start:
	if (CI->getType() != Type::VoidTy)
	CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
	break; // Simply strip out debugging intrinsics

	case Intrinsic::memcpy: {
	// The memcpy intrinsic take an extra alignment argument that the memcpy
	// libc function does not.
	static Function *MemcpyFCache = 0;
	ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
	(*(CI->op_begin()+1))->getType(), MemcpyFCache);
	break;
	}
	case Intrinsic::memmove: {
	// The memmove intrinsic take an extra alignment argument that the memmove
	// libc function does not.
	static Function *MemmoveFCache = 0;
	ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
	(*(CI->op_begin()+1))->getType(), MemmoveFCache);
	break;
	}
	case Intrinsic::memset: {
	// The memset intrinsic take an extra alignment argument that the memset
	// libc function does not.
	static Function *MemsetFCache = 0;
	ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
	(*(CI->op_begin()+1))->getType(), MemsetFCache);
	break;
	}
	case Intrinsic::isunordered: {
	Value *L = CI->getOperand(1);
	Value *R = CI->getOperand(2);

	Value *LIsNan = new SetCondInst(Instruction::SetNE, L, L, "LIsNan", CI);
	Value *RIsNan = new SetCondInst(Instruction::SetNE, R, R, "RIsNan", CI);
	CI->replaceAllUsesWith(
	BinaryOperator::create(Instruction::Or, LIsNan, RIsNan,
	"isunordered", CI));
	break;
	}
	case Intrinsic::sqrt: {
	static Function *sqrtFCache = 0;
	static Function *sqrtfFCache = 0;
	if(CI->getType() == Type::FloatTy)
	ReplaceCallWith("sqrtf", CI, CI->op_begin()+1, CI->op_end(),
	Type::FloatTy, sqrtfFCache);
	else
	ReplaceCallWith("sqrt", CI, CI->op_begin()+1, CI->op_end(),
	Type::DoubleTy, sqrtFCache);
	break;
	}
	}

	assert(CI->use_empty() &&
	"Lowering should have eliminated any uses of the intrinsic call!");
	CI->eraseFromParent();
	}