| //===-- 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 IntrinsicLowering class. | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 |  | 
 | #include "llvm/Constants.h" | 
 | #include "llvm/DerivedTypes.h" | 
 | #include "llvm/Module.h" | 
 | #include "llvm/Instructions.h" | 
 | #include "llvm/Type.h" | 
 | #include "llvm/CodeGen/IntrinsicLowering.h" | 
 | #include "llvm/Support/Streams.h" | 
 | #include "llvm/Target/TargetData.h" | 
 | #include "llvm/ADT/SmallVector.h" | 
 | #include "llvm/ADT/STLExtras.h" | 
 | using namespace llvm; | 
 |  | 
 | template <class ArgIt> | 
 | static void EnsureFunctionExists(Module &M, const char *Name, | 
 |                                  ArgIt ArgBegin, ArgIt ArgEnd, | 
 |                                  const Type *RetTy) { | 
 |   // Insert a correctly-typed definition now. | 
 |   std::vector<const Type *> ParamTys; | 
 |   for (ArgIt I = ArgBegin; I != ArgEnd; ++I) | 
 |     ParamTys.push_back(I->getType()); | 
 |   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, Constant *&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(); | 
 |     // Get or insert the 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)); | 
 |   } | 
 |  | 
 |   SmallVector<Value *, 8> Args(ArgBegin, ArgEnd); | 
 |   CallInst *NewCI = new CallInst(FCache, Args.begin(), Args.end(), | 
 |                                  CI->getName(), CI); | 
 |   if (!CI->use_empty()) | 
 |     CI->replaceAllUsesWith(NewCI); | 
 |   return NewCI; | 
 | } | 
 |  | 
 | void IntrinsicLowering::AddPrototypes(Module &M) { | 
 |   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) | 
 |     if (I->isDeclaration() && !I->use_empty()) | 
 |       switch (I->getIntrinsicID()) { | 
 |       default: break; | 
 |       case Intrinsic::setjmp: | 
 |         EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(), | 
 |                              Type::Int32Ty); | 
 |         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_i32: | 
 |       case Intrinsic::memcpy_i64: | 
 |         M.getOrInsertFunction("memcpy", PointerType::get(Type::Int8Ty), | 
 |                               PointerType::get(Type::Int8Ty),  | 
 |                               PointerType::get(Type::Int8Ty),  | 
 |                               TD.getIntPtrType(), (Type *)0); | 
 |         break; | 
 |       case Intrinsic::memmove_i32: | 
 |       case Intrinsic::memmove_i64: | 
 |         M.getOrInsertFunction("memmove", PointerType::get(Type::Int8Ty), | 
 |                               PointerType::get(Type::Int8Ty),  | 
 |                               PointerType::get(Type::Int8Ty),  | 
 |                               TD.getIntPtrType(), (Type *)0); | 
 |         break; | 
 |       case Intrinsic::memset_i32: | 
 |       case Intrinsic::memset_i64: | 
 |         M.getOrInsertFunction("memset", PointerType::get(Type::Int8Ty), | 
 |                               PointerType::get(Type::Int8Ty), Type::Int32Ty,  | 
 |                               TD.getIntPtrType(), (Type *)0); | 
 |         break; | 
 |       case Intrinsic::sqrt: | 
 |         switch((int)I->arg_begin()->getType()->getTypeID()) { | 
 |         case Type::FloatTyID: | 
 |           EnsureFunctionExists(M, "sqrtf", I->arg_begin(), I->arg_end(), | 
 |                                Type::FloatTy); | 
 |         case Type::DoubleTyID: | 
 |           EnsureFunctionExists(M, "sqrt", I->arg_begin(), I->arg_end(), | 
 |                                Type::DoubleTy); | 
 |         case Type::X86_FP80TyID: | 
 |         case Type::FP128TyID: | 
 |         case Type::PPC_FP128TyID: | 
 |           EnsureFunctionExists(M, "sqrtl", I->arg_begin(), I->arg_end(), | 
 |                                I->arg_begin()->getType()); | 
 |         } | 
 |         break; | 
 |       case Intrinsic::sin: | 
 |         switch((int)I->arg_begin()->getType()->getTypeID()) { | 
 |         case Type::FloatTyID: | 
 |           EnsureFunctionExists(M, "sinf", I->arg_begin(), I->arg_end(), | 
 |                                Type::FloatTy); | 
 |         case Type::DoubleTyID: | 
 |           EnsureFunctionExists(M, "sin", I->arg_begin(), I->arg_end(), | 
 |                                Type::DoubleTy); | 
 |         case Type::X86_FP80TyID: | 
 |         case Type::FP128TyID: | 
 |         case Type::PPC_FP128TyID: | 
 |           EnsureFunctionExists(M, "sinl", I->arg_begin(), I->arg_end(), | 
 |                                I->arg_begin()->getType()); | 
 |         } | 
 |         break; | 
 |       case Intrinsic::cos: | 
 |         switch((int)I->arg_begin()->getType()->getTypeID()) { | 
 |         case Type::FloatTyID: | 
 |           EnsureFunctionExists(M, "cosf", I->arg_begin(), I->arg_end(), | 
 |                                Type::FloatTy); | 
 |         case Type::DoubleTyID: | 
 |           EnsureFunctionExists(M, "cos", I->arg_begin(), I->arg_end(), | 
 |                                Type::DoubleTy); | 
 |         case Type::X86_FP80TyID: | 
 |         case Type::FP128TyID: | 
 |         case Type::PPC_FP128TyID: | 
 |           EnsureFunctionExists(M, "cosl", I->arg_begin(), I->arg_end(), | 
 |                                I->arg_begin()->getType()); | 
 |         } | 
 |         break; | 
 |       case Intrinsic::pow: | 
 |         switch((int)I->arg_begin()->getType()->getTypeID()) { | 
 |         case Type::FloatTyID: | 
 |           EnsureFunctionExists(M, "powf", I->arg_begin(), I->arg_end(), | 
 |                                Type::FloatTy); | 
 |         case Type::DoubleTyID: | 
 |           EnsureFunctionExists(M, "pow", I->arg_begin(), I->arg_end(), | 
 |                                Type::DoubleTy); | 
 |         case Type::X86_FP80TyID: | 
 |         case Type::FP128TyID: | 
 |         case Type::PPC_FP128TyID: | 
 |           EnsureFunctionExists(M, "powl", I->arg_begin(), I->arg_end(), | 
 |                                I->arg_begin()->getType()); | 
 |         } | 
 |         break; | 
 |       } | 
 | } | 
 |  | 
 | /// LowerBSWAP - Emit the code to lower bswap of V before the specified | 
 | /// instruction IP. | 
 | static Value *LowerBSWAP(Value *V, Instruction *IP) { | 
 |   assert(V->getType()->isInteger() && "Can't bswap a non-integer type!"); | 
 |  | 
 |   unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); | 
 |    | 
 |   switch(BitSize) { | 
 |   default: assert(0 && "Unhandled type size of value to byteswap!"); | 
 |   case 16: { | 
 |     Value *Tmp1 = BinaryOperator::createShl(V, | 
 |                                 ConstantInt::get(V->getType(),8),"bswap.2",IP); | 
 |     Value *Tmp2 = BinaryOperator::createLShr(V, | 
 |                                 ConstantInt::get(V->getType(),8),"bswap.1",IP); | 
 |     V = BinaryOperator::createOr(Tmp1, Tmp2, "bswap.i16", IP); | 
 |     break; | 
 |   } | 
 |   case 32: { | 
 |     Value *Tmp4 = BinaryOperator::createShl(V, | 
 |                               ConstantInt::get(V->getType(),24),"bswap.4", IP); | 
 |     Value *Tmp3 = BinaryOperator::createShl(V, | 
 |                               ConstantInt::get(V->getType(),8),"bswap.3",IP); | 
 |     Value *Tmp2 = BinaryOperator::createLShr(V, | 
 |                               ConstantInt::get(V->getType(),8),"bswap.2",IP); | 
 |     Value *Tmp1 = BinaryOperator::createLShr(V, | 
 |                               ConstantInt::get(V->getType(),24),"bswap.1", IP); | 
 |     Tmp3 = BinaryOperator::createAnd(Tmp3,  | 
 |                                      ConstantInt::get(Type::Int32Ty, 0xFF0000), | 
 |                                      "bswap.and3", IP); | 
 |     Tmp2 = BinaryOperator::createAnd(Tmp2,  | 
 |                                      ConstantInt::get(Type::Int32Ty, 0xFF00), | 
 |                                      "bswap.and2", IP); | 
 |     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or1", IP); | 
 |     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or2", IP); | 
 |     V = BinaryOperator::createOr(Tmp4, Tmp2, "bswap.i32", IP); | 
 |     break; | 
 |   } | 
 |   case 64: { | 
 |     Value *Tmp8 = BinaryOperator::createShl(V, | 
 |                               ConstantInt::get(V->getType(),56),"bswap.8", IP); | 
 |     Value *Tmp7 = BinaryOperator::createShl(V, | 
 |                               ConstantInt::get(V->getType(),40),"bswap.7", IP); | 
 |     Value *Tmp6 = BinaryOperator::createShl(V, | 
 |                               ConstantInt::get(V->getType(),24),"bswap.6", IP); | 
 |     Value *Tmp5 = BinaryOperator::createShl(V, | 
 |                               ConstantInt::get(V->getType(),8),"bswap.5", IP); | 
 |     Value* Tmp4 = BinaryOperator::createLShr(V, | 
 |                               ConstantInt::get(V->getType(),8),"bswap.4", IP); | 
 |     Value* Tmp3 = BinaryOperator::createLShr(V, | 
 |                               ConstantInt::get(V->getType(),24),"bswap.3", IP); | 
 |     Value* Tmp2 = BinaryOperator::createLShr(V, | 
 |                               ConstantInt::get(V->getType(),40),"bswap.2", IP); | 
 |     Value* Tmp1 = BinaryOperator::createLShr(V, | 
 |                               ConstantInt::get(V->getType(),56),"bswap.1", IP); | 
 |     Tmp7 = BinaryOperator::createAnd(Tmp7, | 
 |                              ConstantInt::get(Type::Int64Ty,  | 
 |                                0xFF000000000000ULL), | 
 |                              "bswap.and7", IP); | 
 |     Tmp6 = BinaryOperator::createAnd(Tmp6, | 
 |                              ConstantInt::get(Type::Int64Ty, 0xFF0000000000ULL), | 
 |                              "bswap.and6", IP); | 
 |     Tmp5 = BinaryOperator::createAnd(Tmp5, | 
 |                              ConstantInt::get(Type::Int64Ty, 0xFF00000000ULL), | 
 |                              "bswap.and5", IP); | 
 |     Tmp4 = BinaryOperator::createAnd(Tmp4, | 
 |                              ConstantInt::get(Type::Int64Ty, 0xFF000000ULL), | 
 |                              "bswap.and4", IP); | 
 |     Tmp3 = BinaryOperator::createAnd(Tmp3, | 
 |                              ConstantInt::get(Type::Int64Ty, 0xFF0000ULL), | 
 |                              "bswap.and3", IP); | 
 |     Tmp2 = BinaryOperator::createAnd(Tmp2, | 
 |                              ConstantInt::get(Type::Int64Ty, 0xFF00ULL), | 
 |                              "bswap.and2", IP); | 
 |     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp7, "bswap.or1", IP); | 
 |     Tmp6 = BinaryOperator::createOr(Tmp6, Tmp5, "bswap.or2", IP); | 
 |     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or3", IP); | 
 |     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or4", IP); | 
 |     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp6, "bswap.or5", IP); | 
 |     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp2, "bswap.or6", IP); | 
 |     V = BinaryOperator::createOr(Tmp8, Tmp4, "bswap.i64", IP); | 
 |     break; | 
 |   } | 
 |   } | 
 |   return V; | 
 | } | 
 |  | 
 | /// LowerCTPOP - Emit the code to lower ctpop of V before the specified | 
 | /// instruction IP. | 
 | 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 | 
 |   }; | 
 |  | 
 |   unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); | 
 |   unsigned WordSize = (BitSize + 63) / 64; | 
 |   Value *Count = ConstantInt::get(V->getType(), 0); | 
 |  | 
 |   for (unsigned n = 0; n < WordSize; ++n) { | 
 |     Value *PartValue = V; | 
 |     for (unsigned i = 1, ct = 0; i < (BitSize>64 ? 64 : BitSize);  | 
 |          i <<= 1, ++ct) { | 
 |       Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]); | 
 |       Value *LHS = BinaryOperator::createAnd( | 
 |                      PartValue, MaskCst, "cppop.and1", IP); | 
 |       Value *VShift = BinaryOperator::createLShr(PartValue, | 
 |                         ConstantInt::get(V->getType(), i), "ctpop.sh", IP); | 
 |       Value *RHS = BinaryOperator::createAnd(VShift, MaskCst, "cppop.and2", IP); | 
 |       PartValue = BinaryOperator::createAdd(LHS, RHS, "ctpop.step", IP); | 
 |     } | 
 |     Count = BinaryOperator::createAdd(PartValue, Count, "ctpop.part", IP); | 
 |     if (BitSize > 64) { | 
 |       V = BinaryOperator::createLShr(V, ConstantInt::get(V->getType(), 64),  | 
 |                                      "ctpop.part.sh", IP); | 
 |       BitSize -= 64; | 
 |     } | 
 |   } | 
 |  | 
 |   return Count; | 
 | } | 
 |  | 
 | /// LowerCTLZ - Emit the code to lower ctlz of V before the specified | 
 | /// instruction IP. | 
 | static Value *LowerCTLZ(Value *V, Instruction *IP) { | 
 |  | 
 |   unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); | 
 |   for (unsigned i = 1; i < BitSize; i <<= 1) { | 
 |     Value *ShVal = ConstantInt::get(V->getType(), i); | 
 |     ShVal = BinaryOperator::createLShr(V, ShVal, "ctlz.sh", IP); | 
 |     V = BinaryOperator::createOr(V, ShVal, "ctlz.step", IP); | 
 |   } | 
 |  | 
 |   V = BinaryOperator::createNot(V, "", IP); | 
 |   return LowerCTPOP(V, IP); | 
 | } | 
 |  | 
 | /// Convert the llvm.part.select.iX.iY intrinsic. This intrinsic takes  | 
 | /// three integer arguments. The first argument is the Value from which the | 
 | /// bits will be selected. It may be of any bit width. The second and third | 
 | /// arguments specify a range of bits to select with the second argument  | 
 | /// specifying the low bit and the third argument specifying the high bit. Both | 
 | /// must be type i32. The result is the corresponding selected bits from the | 
 | /// Value in the same width as the Value (first argument). If the low bit index | 
 | /// is higher than the high bit index then the inverse selection is done and  | 
 | /// the bits are returned in inverse order.  | 
 | /// @brief Lowering of llvm.part.select intrinsic. | 
 | static Instruction *LowerPartSelect(CallInst *CI) { | 
 |   // Make sure we're dealing with a part select intrinsic here | 
 |   Function *F = CI->getCalledFunction(); | 
 |   const FunctionType *FT = F->getFunctionType(); | 
 |   if (!F->isDeclaration() || !FT->getReturnType()->isInteger() || | 
 |       FT->getNumParams() != 3 || !FT->getParamType(0)->isInteger() || | 
 |       !FT->getParamType(1)->isInteger() || !FT->getParamType(2)->isInteger()) | 
 |     return CI; | 
 |  | 
 |   // Get the intrinsic implementation function by converting all the . to _ | 
 |   // in the intrinsic's function name and then reconstructing the function | 
 |   // declaration. | 
 |   std::string Name(F->getName()); | 
 |   for (unsigned i = 4; i < Name.length(); ++i) | 
 |     if (Name[i] == '.') | 
 |       Name[i] = '_'; | 
 |   Module* M = F->getParent(); | 
 |   F = cast<Function>(M->getOrInsertFunction(Name, FT)); | 
 |   F->setLinkage(GlobalValue::WeakLinkage); | 
 |  | 
 |   // If we haven't defined the impl function yet, do so now | 
 |   if (F->isDeclaration()) { | 
 |  | 
 |     // Get the arguments to the function | 
 |     Function::arg_iterator args = F->arg_begin(); | 
 |     Value* Val = args++; Val->setName("Val"); | 
 |     Value* Lo = args++; Lo->setName("Lo"); | 
 |     Value* Hi  = args++; Hi->setName("High"); | 
 |  | 
 |     // We want to select a range of bits here such that [Hi, Lo] is shifted | 
 |     // down to the low bits. However, it is quite possible that Hi is smaller | 
 |     // than Lo in which case the bits have to be reversed.  | 
 |      | 
 |     // Create the blocks we will need for the two cases (forward, reverse) | 
 |     BasicBlock* CurBB   = new BasicBlock("entry", F); | 
 |     BasicBlock *RevSize = new BasicBlock("revsize", CurBB->getParent()); | 
 |     BasicBlock *FwdSize = new BasicBlock("fwdsize", CurBB->getParent()); | 
 |     BasicBlock *Compute = new BasicBlock("compute", CurBB->getParent()); | 
 |     BasicBlock *Reverse = new BasicBlock("reverse", CurBB->getParent()); | 
 |     BasicBlock *RsltBlk = new BasicBlock("result",  CurBB->getParent()); | 
 |  | 
 |     // Cast Hi and Lo to the size of Val so the widths are all the same | 
 |     if (Hi->getType() != Val->getType()) | 
 |       Hi = CastInst::createIntegerCast(Hi, Val->getType(), false,  | 
 |                                          "tmp", CurBB); | 
 |     if (Lo->getType() != Val->getType()) | 
 |       Lo = CastInst::createIntegerCast(Lo, Val->getType(), false,  | 
 |                                           "tmp", CurBB); | 
 |  | 
 |     // Compute a few things that both cases will need, up front. | 
 |     Constant* Zero = ConstantInt::get(Val->getType(), 0); | 
 |     Constant* One = ConstantInt::get(Val->getType(), 1); | 
 |     Constant* AllOnes = ConstantInt::getAllOnesValue(Val->getType()); | 
 |  | 
 |     // Compare the Hi and Lo bit positions. This is used to determine  | 
 |     // which case we have (forward or reverse) | 
 |     ICmpInst *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, Hi, Lo, "less",CurBB); | 
 |     new BranchInst(RevSize, FwdSize, Cmp, CurBB); | 
 |  | 
 |     // First, copmute the number of bits in the forward case. | 
 |     Instruction* FBitSize =  | 
 |       BinaryOperator::createSub(Hi, Lo,"fbits", FwdSize); | 
 |     new BranchInst(Compute, FwdSize); | 
 |  | 
 |     // Second, compute the number of bits in the reverse case. | 
 |     Instruction* RBitSize =  | 
 |       BinaryOperator::createSub(Lo, Hi, "rbits", RevSize); | 
 |     new BranchInst(Compute, RevSize); | 
 |  | 
 |     // Now, compute the bit range. Start by getting the bitsize and the shift | 
 |     // amount (either Hi or Lo) from PHI nodes. Then we compute a mask for  | 
 |     // the number of bits we want in the range. We shift the bits down to the  | 
 |     // least significant bits, apply the mask to zero out unwanted high bits,  | 
 |     // and we have computed the "forward" result. It may still need to be  | 
 |     // reversed. | 
 |  | 
 |     // Get the BitSize from one of the two subtractions | 
 |     PHINode *BitSize = new PHINode(Val->getType(), "bits", Compute); | 
 |     BitSize->reserveOperandSpace(2); | 
 |     BitSize->addIncoming(FBitSize, FwdSize); | 
 |     BitSize->addIncoming(RBitSize, RevSize); | 
 |  | 
 |     // Get the ShiftAmount as the smaller of Hi/Lo | 
 |     PHINode *ShiftAmt = new PHINode(Val->getType(), "shiftamt", Compute); | 
 |     ShiftAmt->reserveOperandSpace(2); | 
 |     ShiftAmt->addIncoming(Lo, FwdSize); | 
 |     ShiftAmt->addIncoming(Hi, RevSize); | 
 |  | 
 |     // Increment the bit size | 
 |     Instruction *BitSizePlusOne =  | 
 |       BinaryOperator::createAdd(BitSize, One, "bits", Compute); | 
 |  | 
 |     // Create a Mask to zero out the high order bits. | 
 |     Instruction* Mask =  | 
 |       BinaryOperator::createShl(AllOnes, BitSizePlusOne, "mask", Compute); | 
 |     Mask = BinaryOperator::createNot(Mask, "mask", Compute); | 
 |  | 
 |     // Shift the bits down and apply the mask | 
 |     Instruction* FRes =  | 
 |       BinaryOperator::createLShr(Val, ShiftAmt, "fres", Compute); | 
 |     FRes = BinaryOperator::createAnd(FRes, Mask, "fres", Compute); | 
 |     new BranchInst(Reverse, RsltBlk, Cmp, Compute); | 
 |  | 
 |     // In the Reverse block we have the mask already in FRes but we must reverse | 
 |     // it by shifting FRes bits right and putting them in RRes by shifting them  | 
 |     // in from left. | 
 |  | 
 |     // First set up our loop counters | 
 |     PHINode *Count = new PHINode(Val->getType(), "count", Reverse); | 
 |     Count->reserveOperandSpace(2); | 
 |     Count->addIncoming(BitSizePlusOne, Compute); | 
 |  | 
 |     // Next, get the value that we are shifting. | 
 |     PHINode *BitsToShift   = new PHINode(Val->getType(), "val", Reverse); | 
 |     BitsToShift->reserveOperandSpace(2); | 
 |     BitsToShift->addIncoming(FRes, Compute); | 
 |  | 
 |     // Finally, get the result of the last computation | 
 |     PHINode *RRes  = new PHINode(Val->getType(), "rres", Reverse); | 
 |     RRes->reserveOperandSpace(2); | 
 |     RRes->addIncoming(Zero, Compute); | 
 |  | 
 |     // Decrement the counter | 
 |     Instruction *Decr = BinaryOperator::createSub(Count, One, "decr", Reverse); | 
 |     Count->addIncoming(Decr, Reverse); | 
 |  | 
 |     // Compute the Bit that we want to move | 
 |     Instruction *Bit =  | 
 |       BinaryOperator::createAnd(BitsToShift, One, "bit", Reverse); | 
 |  | 
 |     // Compute the new value for next iteration. | 
 |     Instruction *NewVal =  | 
 |       BinaryOperator::createLShr(BitsToShift, One, "rshift", Reverse); | 
 |     BitsToShift->addIncoming(NewVal, Reverse); | 
 |  | 
 |     // Shift the bit into the low bits of the result. | 
 |     Instruction *NewRes =  | 
 |       BinaryOperator::createShl(RRes, One, "lshift", Reverse); | 
 |     NewRes = BinaryOperator::createOr(NewRes, Bit, "addbit", Reverse); | 
 |     RRes->addIncoming(NewRes, Reverse); | 
 |      | 
 |     // Terminate loop if we've moved all the bits. | 
 |     ICmpInst *Cond =  | 
 |       new ICmpInst(ICmpInst::ICMP_EQ, Decr, Zero, "cond", Reverse); | 
 |     new BranchInst(RsltBlk, Reverse, Cond, Reverse); | 
 |  | 
 |     // Finally, in the result block, select one of the two results with a PHI | 
 |     // node and return the result; | 
 |     CurBB = RsltBlk; | 
 |     PHINode *BitSelect = new PHINode(Val->getType(), "part_select", CurBB); | 
 |     BitSelect->reserveOperandSpace(2); | 
 |     BitSelect->addIncoming(FRes, Compute); | 
 |     BitSelect->addIncoming(NewRes, Reverse); | 
 |     new ReturnInst(BitSelect, CurBB); | 
 |   } | 
 |  | 
 |   // Return a call to the implementation function | 
 |   Value *Args[] = { | 
 |     CI->getOperand(1), | 
 |     CI->getOperand(2), | 
 |     CI->getOperand(3) | 
 |   }; | 
 |   return new CallInst(F, Args, array_endof(Args), CI->getName(), CI); | 
 | } | 
 |  | 
 | /// Convert the llvm.part.set.iX.iY.iZ intrinsic. This intrinsic takes  | 
 | /// four integer arguments (iAny %Value, iAny %Replacement, i32 %Low, i32 %High) | 
 | /// The first two arguments can be any bit width. The result is the same width | 
 | /// as %Value. The operation replaces bits between %Low and %High with the value | 
 | /// in %Replacement. If %Replacement is not the same width, it is truncated or | 
 | /// zero extended as appropriate to fit the bits being replaced. If %Low is | 
 | /// greater than %High then the inverse set of bits are replaced. | 
 | /// @brief Lowering of llvm.bit.part.set intrinsic. | 
 | static Instruction *LowerPartSet(CallInst *CI) { | 
 |   // Make sure we're dealing with a part select intrinsic here | 
 |   Function *F = CI->getCalledFunction(); | 
 |   const FunctionType *FT = F->getFunctionType(); | 
 |   if (!F->isDeclaration() || !FT->getReturnType()->isInteger() || | 
 |       FT->getNumParams() != 4 || !FT->getParamType(0)->isInteger() || | 
 |       !FT->getParamType(1)->isInteger() || !FT->getParamType(2)->isInteger() || | 
 |       !FT->getParamType(3)->isInteger()) | 
 |     return CI; | 
 |  | 
 |   // Get the intrinsic implementation function by converting all the . to _ | 
 |   // in the intrinsic's function name and then reconstructing the function | 
 |   // declaration. | 
 |   std::string Name(F->getName()); | 
 |   for (unsigned i = 4; i < Name.length(); ++i) | 
 |     if (Name[i] == '.') | 
 |       Name[i] = '_'; | 
 |   Module* M = F->getParent(); | 
 |   F = cast<Function>(M->getOrInsertFunction(Name, FT)); | 
 |   F->setLinkage(GlobalValue::WeakLinkage); | 
 |  | 
 |   // If we haven't defined the impl function yet, do so now | 
 |   if (F->isDeclaration()) { | 
 |     // Get the arguments for the function. | 
 |     Function::arg_iterator args = F->arg_begin(); | 
 |     Value* Val = args++; Val->setName("Val"); | 
 |     Value* Rep = args++; Rep->setName("Rep"); | 
 |     Value* Lo  = args++; Lo->setName("Lo"); | 
 |     Value* Hi  = args++; Hi->setName("Hi"); | 
 |  | 
 |     // Get some types we need | 
 |     const IntegerType* ValTy = cast<IntegerType>(Val->getType()); | 
 |     const IntegerType* RepTy = cast<IntegerType>(Rep->getType()); | 
 |     uint32_t ValBits = ValTy->getBitWidth(); | 
 |     uint32_t RepBits = RepTy->getBitWidth(); | 
 |  | 
 |     // Constant Definitions | 
 |     ConstantInt* RepBitWidth = ConstantInt::get(Type::Int32Ty, RepBits); | 
 |     ConstantInt* RepMask = ConstantInt::getAllOnesValue(RepTy); | 
 |     ConstantInt* ValMask = ConstantInt::getAllOnesValue(ValTy); | 
 |     ConstantInt* One = ConstantInt::get(Type::Int32Ty, 1); | 
 |     ConstantInt* ValOne = ConstantInt::get(ValTy, 1); | 
 |     ConstantInt* Zero = ConstantInt::get(Type::Int32Ty, 0); | 
 |     ConstantInt* ValZero = ConstantInt::get(ValTy, 0); | 
 |  | 
 |     // Basic blocks we fill in below. | 
 |     BasicBlock* entry = new BasicBlock("entry", F, 0); | 
 |     BasicBlock* large = new BasicBlock("large", F, 0); | 
 |     BasicBlock* small = new BasicBlock("small", F, 0); | 
 |     BasicBlock* reverse = new BasicBlock("reverse", F, 0); | 
 |     BasicBlock* result = new BasicBlock("result", F, 0); | 
 |  | 
 |     // BASIC BLOCK: entry | 
 |     // First, get the number of bits that we're placing as an i32 | 
 |     ICmpInst* is_forward =  | 
 |       new ICmpInst(ICmpInst::ICMP_ULT, Lo, Hi, "", entry); | 
 |     SelectInst* Hi_pn = new SelectInst(is_forward, Hi, Lo, "", entry); | 
 |     SelectInst* Lo_pn = new SelectInst(is_forward, Lo, Hi, "", entry); | 
 |     BinaryOperator* NumBits = BinaryOperator::createSub(Hi_pn, Lo_pn, "",entry); | 
 |     NumBits = BinaryOperator::createAdd(NumBits, One, "", entry); | 
 |     // Now, convert Lo and Hi to ValTy bit width | 
 |     if (ValBits > 32) { | 
 |       Lo = new ZExtInst(Lo_pn, ValTy, "", entry); | 
 |     } else if (ValBits < 32) { | 
 |       Lo = new TruncInst(Lo_pn, ValTy, "", entry); | 
 |     } | 
 |     // Determine if the replacement bits are larger than the number of bits we | 
 |     // are replacing and deal with it. | 
 |     ICmpInst* is_large =  | 
 |       new ICmpInst(ICmpInst::ICMP_ULT, NumBits, RepBitWidth, "", entry); | 
 |     new BranchInst(large, small, is_large, entry); | 
 |  | 
 |     // BASIC BLOCK: large | 
 |     Instruction* MaskBits =  | 
 |       BinaryOperator::createSub(RepBitWidth, NumBits, "", large); | 
 |     MaskBits = CastInst::createIntegerCast(MaskBits, RepMask->getType(),  | 
 |                                            false, "", large); | 
 |     BinaryOperator* Mask1 =  | 
 |       BinaryOperator::createLShr(RepMask, MaskBits, "", large); | 
 |     BinaryOperator* Rep2 = BinaryOperator::createAnd(Mask1, Rep, "", large); | 
 |     new BranchInst(small, large); | 
 |  | 
 |     // BASIC BLOCK: small | 
 |     PHINode* Rep3 = new PHINode(RepTy, "", small); | 
 |     Rep3->reserveOperandSpace(2); | 
 |     Rep3->addIncoming(Rep2, large); | 
 |     Rep3->addIncoming(Rep, entry); | 
 |     Value* Rep4 = Rep3; | 
 |     if (ValBits > RepBits) | 
 |       Rep4 = new ZExtInst(Rep3, ValTy, "", small); | 
 |     else if (ValBits < RepBits) | 
 |       Rep4 = new TruncInst(Rep3, ValTy, "", small); | 
 |     new BranchInst(result, reverse, is_forward, small); | 
 |  | 
 |     // BASIC BLOCK: reverse (reverses the bits of the replacement) | 
 |     // Set up our loop counter as a PHI so we can decrement on each iteration. | 
 |     // We will loop for the number of bits in the replacement value. | 
 |     PHINode *Count = new PHINode(Type::Int32Ty, "count", reverse); | 
 |     Count->reserveOperandSpace(2); | 
 |     Count->addIncoming(NumBits, small); | 
 |  | 
 |     // Get the value that we are shifting bits out of as a PHI because | 
 |     // we'll change this with each iteration. | 
 |     PHINode *BitsToShift   = new PHINode(Val->getType(), "val", reverse); | 
 |     BitsToShift->reserveOperandSpace(2); | 
 |     BitsToShift->addIncoming(Rep4, small); | 
 |  | 
 |     // Get the result of the last computation or zero on first iteration | 
 |     PHINode *RRes  = new PHINode(Val->getType(), "rres", reverse); | 
 |     RRes->reserveOperandSpace(2); | 
 |     RRes->addIncoming(ValZero, small); | 
 |  | 
 |     // Decrement the loop counter by one | 
 |     Instruction *Decr = BinaryOperator::createSub(Count, One, "", reverse); | 
 |     Count->addIncoming(Decr, reverse); | 
 |  | 
 |     // Get the bit that we want to move into the result | 
 |     Value *Bit = BinaryOperator::createAnd(BitsToShift, ValOne, "", reverse); | 
 |  | 
 |     // Compute the new value of the bits to shift for the next iteration. | 
 |     Value *NewVal = BinaryOperator::createLShr(BitsToShift, ValOne,"", reverse); | 
 |     BitsToShift->addIncoming(NewVal, reverse); | 
 |  | 
 |     // Shift the bit we extracted into the low bit of the result. | 
 |     Instruction *NewRes = BinaryOperator::createShl(RRes, ValOne, "", reverse); | 
 |     NewRes = BinaryOperator::createOr(NewRes, Bit, "", reverse); | 
 |     RRes->addIncoming(NewRes, reverse); | 
 |      | 
 |     // Terminate loop if we've moved all the bits. | 
 |     ICmpInst *Cond = new ICmpInst(ICmpInst::ICMP_EQ, Decr, Zero, "", reverse); | 
 |     new BranchInst(result, reverse, Cond, reverse); | 
 |  | 
 |     // BASIC BLOCK: result | 
 |     PHINode *Rplcmnt  = new PHINode(Val->getType(), "", result); | 
 |     Rplcmnt->reserveOperandSpace(2); | 
 |     Rplcmnt->addIncoming(NewRes, reverse); | 
 |     Rplcmnt->addIncoming(Rep4, small); | 
 |     Value* t0   = CastInst::createIntegerCast(NumBits,ValTy,false,"",result); | 
 |     Value* t1   = BinaryOperator::createShl(ValMask, Lo, "", result); | 
 |     Value* t2   = BinaryOperator::createNot(t1, "", result); | 
 |     Value* t3   = BinaryOperator::createShl(t1, t0, "", result); | 
 |     Value* t4   = BinaryOperator::createOr(t2, t3, "", result); | 
 |     Value* t5   = BinaryOperator::createAnd(t4, Val, "", result); | 
 |     Value* t6   = BinaryOperator::createShl(Rplcmnt, Lo, "", result); | 
 |     Value* Rslt = BinaryOperator::createOr(t5, t6, "part_set", result); | 
 |     new ReturnInst(Rslt, result); | 
 |   } | 
 |  | 
 |   // Return a call to the implementation function | 
 |   Value *Args[] = { | 
 |     CI->getOperand(1), | 
 |     CI->getOperand(2), | 
 |     CI->getOperand(3), | 
 |     CI->getOperand(4) | 
 |   }; | 
 |   return new CallInst(F, Args, array_endof(Args), CI->getName(), CI); | 
 | } | 
 |  | 
 |  | 
 | void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) { | 
 |   Function *Callee = CI->getCalledFunction(); | 
 |   assert(Callee && "Cannot lower an indirect call!"); | 
 |  | 
 |   switch (Callee->getIntrinsicID()) { | 
 |   case Intrinsic::not_intrinsic: | 
 |     cerr << "Cannot lower a call to a non-intrinsic function '" | 
 |          << Callee->getName() << "'!\n"; | 
 |     abort(); | 
 |   default: | 
 |     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 Constant *SetjmpFCache = 0; | 
 |     Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(), | 
 |                                Type::Int32Ty, 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 Constant *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 Constant *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::bswap: | 
 |     CI->replaceAllUsesWith(LowerBSWAP(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::part_select: | 
 |     CI->replaceAllUsesWith(LowerPartSelect(CI)); | 
 |     break; | 
 |  | 
 |   case Intrinsic::part_set: | 
 |     CI->replaceAllUsesWith(LowerPartSet(CI)); | 
 |     break; | 
 |  | 
 |   case Intrinsic::stacksave: | 
 |   case Intrinsic::stackrestore: { | 
 |     static bool Warned = false; | 
 |     if (!Warned) | 
 |       cerr << "WARNING: this target does not support the llvm.stack" | 
 |            << (Callee->getIntrinsicID() == Intrinsic::stacksave ? | 
 |                "save" : "restore") << " intrinsic.\n"; | 
 |     Warned = true; | 
 |     if (Callee->getIntrinsicID() == Intrinsic::stacksave) | 
 |       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); | 
 |     break; | 
 |   } | 
 |      | 
 |   case Intrinsic::returnaddress: | 
 |   case Intrinsic::frameaddress: | 
 |     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::readcyclecounter: { | 
 |     cerr << "WARNING: this target does not support the llvm.readcyclecoun" | 
 |          << "ter intrinsic.  It is being lowered to a constant 0\n"; | 
 |     CI->replaceAllUsesWith(ConstantInt::get(Type::Int64Ty, 0)); | 
 |     break; | 
 |   } | 
 |  | 
 |   case Intrinsic::dbg_stoppoint: | 
 |   case Intrinsic::dbg_region_start: | 
 |   case Intrinsic::dbg_region_end: | 
 |   case Intrinsic::dbg_func_start: | 
 |   case Intrinsic::dbg_declare: | 
 |     break;    // Simply strip out debugging intrinsics | 
 |  | 
 |   case Intrinsic::eh_exception: | 
 |   case Intrinsic::eh_selector_i32: | 
 |   case Intrinsic::eh_selector_i64: | 
 |     CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); | 
 |     break; | 
 |  | 
 |   case Intrinsic::eh_typeid_for_i32: | 
 |   case Intrinsic::eh_typeid_for_i64: | 
 |     // Return something different to eh_selector. | 
 |     CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1)); | 
 |     break; | 
 |  | 
 |   case Intrinsic::var_annotation: | 
 |     break;   // Strip out annotate intrinsic | 
 |      | 
 |   case Intrinsic::memcpy_i32: | 
 |   case Intrinsic::memcpy_i64: { | 
 |     static Constant *MemcpyFCache = 0; | 
 |     Value *Size = CI->getOperand(3); | 
 |     const Type *IntPtr = TD.getIntPtrType(); | 
 |     if (Size->getType()->getPrimitiveSizeInBits() < | 
 |         IntPtr->getPrimitiveSizeInBits()) | 
 |       Size = new ZExtInst(Size, IntPtr, "", CI); | 
 |     else if (Size->getType()->getPrimitiveSizeInBits() > | 
 |              IntPtr->getPrimitiveSizeInBits()) | 
 |       Size = new TruncInst(Size, IntPtr, "", CI); | 
 |     Value *Ops[3]; | 
 |     Ops[0] = CI->getOperand(1); | 
 |     Ops[1] = CI->getOperand(2); | 
 |     Ops[2] = Size; | 
 |     ReplaceCallWith("memcpy", CI, Ops, Ops+3, CI->getOperand(1)->getType(), | 
 |                     MemcpyFCache); | 
 |     break; | 
 |   } | 
 |   case Intrinsic::memmove_i32:  | 
 |   case Intrinsic::memmove_i64: { | 
 |     static Constant *MemmoveFCache = 0; | 
 |     Value *Size = CI->getOperand(3); | 
 |     const Type *IntPtr = TD.getIntPtrType(); | 
 |     if (Size->getType()->getPrimitiveSizeInBits() < | 
 |         IntPtr->getPrimitiveSizeInBits()) | 
 |       Size = new ZExtInst(Size, IntPtr, "", CI); | 
 |     else if (Size->getType()->getPrimitiveSizeInBits() > | 
 |              IntPtr->getPrimitiveSizeInBits()) | 
 |       Size = new TruncInst(Size, IntPtr, "", CI); | 
 |     Value *Ops[3]; | 
 |     Ops[0] = CI->getOperand(1); | 
 |     Ops[1] = CI->getOperand(2); | 
 |     Ops[2] = Size; | 
 |     ReplaceCallWith("memmove", CI, Ops, Ops+3, CI->getOperand(1)->getType(), | 
 |                     MemmoveFCache); | 
 |     break; | 
 |   } | 
 |   case Intrinsic::memset_i32: | 
 |   case Intrinsic::memset_i64: { | 
 |     static Constant *MemsetFCache = 0; | 
 |     Value *Size = CI->getOperand(3); | 
 |     const Type *IntPtr = TD.getIntPtrType(); | 
 |     if (Size->getType()->getPrimitiveSizeInBits() < | 
 |         IntPtr->getPrimitiveSizeInBits()) | 
 |       Size = new ZExtInst(Size, IntPtr, "", CI); | 
 |     else if (Size->getType()->getPrimitiveSizeInBits() > | 
 |              IntPtr->getPrimitiveSizeInBits()) | 
 |       Size = new TruncInst(Size, IntPtr, "", CI); | 
 |     Value *Ops[3]; | 
 |     Ops[0] = CI->getOperand(1); | 
 |     // Extend the amount to i32. | 
 |     Ops[1] = new ZExtInst(CI->getOperand(2), Type::Int32Ty, "", CI); | 
 |     Ops[2] = Size; | 
 |     ReplaceCallWith("memset", CI, Ops, Ops+3, CI->getOperand(1)->getType(), | 
 |                     MemsetFCache); | 
 |     break; | 
 |   } | 
 |   case Intrinsic::sqrt: { | 
 |     static Constant *sqrtfFCache = 0; | 
 |     static Constant *sqrtFCache = 0; | 
 |     static Constant *sqrtLDCache = 0; | 
 |     switch (CI->getOperand(1)->getType()->getTypeID()) { | 
 |     default: assert(0 && "Invalid type in sqrt"); abort(); | 
 |     case Type::FloatTyID: | 
 |       ReplaceCallWith("sqrtf", CI, CI->op_begin()+1, CI->op_end(), | 
 |                     Type::FloatTy, sqrtfFCache); | 
 |       break; | 
 |     case Type::DoubleTyID: | 
 |       ReplaceCallWith("sqrt", CI, CI->op_begin()+1, CI->op_end(), | 
 |                     Type::DoubleTy, sqrtFCache); | 
 |       break; | 
 |     case Type::X86_FP80TyID: | 
 |     case Type::FP128TyID: | 
 |     case Type::PPC_FP128TyID: | 
 |       ReplaceCallWith("sqrtl", CI, CI->op_begin()+1, CI->op_end(), | 
 |                     CI->getOperand(1)->getType(), sqrtLDCache); | 
 |       break; | 
 |     } | 
 |     break; | 
 |   } | 
 |   case Intrinsic::flt_rounds: | 
 |      // Lower to "round to the nearest" | 
 |      if (CI->getType() != Type::VoidTy) | 
 |        CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1)); | 
 |      break; | 
 |   } | 
 |  | 
 |   assert(CI->use_empty() && | 
 |          "Lowering should have eliminated any uses of the intrinsic call!"); | 
 |   CI->eraseFromParent(); | 
 | } |