lib/CodeGen/IntrinsicLowering.cpp

   1 //===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the IntrinsicLowering class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/CodeGen/IntrinsicLowering.h"
  15 #include "llvm/Constants.h"
  16 #include "llvm/DerivedTypes.h"
  17 #include "llvm/Module.h"
  18 #include "llvm/Instructions.h"
  19 #include "llvm/Type.h"
  20 #include <iostream>
  21
  22 using namespace llvm;
  23
  24 template <class ArgIt>
  25 static Function *EnsureFunctionExists(Module &M, const char *Name,
  26                                       ArgIt ArgBegin, ArgIt ArgEnd,
  27                                       const Type *RetTy) {
  28   if (Function *F = M.getNamedFunction(Name)) return F;
  29   // It doesn't already exist in the program, insert a new definition now.
  30   std::vector<const Type *> ParamTys;
  31   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  32     ParamTys.push_back(I->getType());
  33   return M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
  34 }
  35
  36 /// ReplaceCallWith - This function is used when we want to lower an intrinsic
  37 /// call to a call of an external function.  This handles hard cases such as
  38 /// when there was already a prototype for the external function, and if that
  39 /// prototype doesn't match the arguments we expect to pass in.
  40 template <class ArgIt>
  41 static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
  42                                  ArgIt ArgBegin, ArgIt ArgEnd,
  43                                  const unsigned *castOpcodes,
  44                                  const Type *RetTy, Function *&FCache) {
  45   if (!FCache) {
  46     // If we haven't already looked up this function, check to see if the
  47     // program already contains a function with this name.
  48     Module *M = CI->getParent()->getParent()->getParent();
  49     FCache = M->getNamedFunction(NewFn);
  50     if (!FCache) {
  51       // It doesn't already exist in the program, insert a new definition now.
  52       std::vector<const Type *> ParamTys;
  53       for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  54         ParamTys.push_back((*I)->getType());
  55       FCache = M->getOrInsertFunction(NewFn,
  56                                      FunctionType::get(RetTy, ParamTys, false));
  57     }
  58    }
  59
  60   const FunctionType *FT = FCache->getFunctionType();
  61   std::vector<Value*> Operands;
  62   unsigned ArgNo = 0;
  63   for (ArgIt I = ArgBegin; I != ArgEnd && ArgNo != FT->getNumParams();
  64        ++I, ++ArgNo) {
  65     Value *Arg = *I;
  66     if (Arg->getType() != FT->getParamType(ArgNo))
  67       if (castOpcodes[ArgNo])
  68         Arg = CastInst::create(Instruction::CastOps(castOpcodes[ArgNo]),
  69           Arg, FT->getParamType(ArgNo), Arg->getName(), CI);
  70       else
  71         Arg = CastInst::createInferredCast(Arg, FT->getParamType(ArgNo),
  72                                            Arg->getName(), CI);
  73     Operands.push_back(Arg);
  74   }
  75   // Pass nulls into any additional arguments...
  76   for (; ArgNo != FT->getNumParams(); ++ArgNo)
  77     Operands.push_back(Constant::getNullValue(FT->getParamType(ArgNo)));
  78
  79   std::string Name = CI->getName(); CI->setName("");
  80   if (FT->getReturnType() == Type::VoidTy) Name.clear();
  81   CallInst *NewCI = new CallInst(FCache, Operands, Name, CI);
  82   if (!CI->use_empty()) {
  83     Value *V = NewCI;
  84     if (CI->getType() != NewCI->getType())
  85       V = CastInst::createInferredCast(NewCI, CI->getType(), Name, CI);
  86     CI->replaceAllUsesWith(V);
  87   }
  88   return NewCI;
  89 }
  90
  91 void IntrinsicLowering::AddPrototypes(Module &M) {
  92   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
  93     if (I->isExternal() && !I->use_empty())
  94       switch (I->getIntrinsicID()) {
  95       default: break;
  96       case Intrinsic::setjmp:
  97         EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(),
  98                              Type::IntTy);
  99         break;
 100       case Intrinsic::longjmp:
 101         EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(),
 102                              Type::VoidTy);
 103         break;
 104       case Intrinsic::siglongjmp:
 105         EnsureFunctionExists(M, "abort", I->arg_end(), I->arg_end(),
 106                              Type::VoidTy);
 107         break;
 108       case Intrinsic::memcpy_i32:
 109       case Intrinsic::memcpy_i64:
 110         EnsureFunctionExists(M, "memcpy", I->arg_begin(), --I->arg_end(),
 111                              I->arg_begin()->getType());
 112         break;
 113       case Intrinsic::memmove_i32:
 114       case Intrinsic::memmove_i64:
 115         EnsureFunctionExists(M, "memmove", I->arg_begin(), --I->arg_end(),
 116                              I->arg_begin()->getType());
 117         break;
 118       case Intrinsic::memset_i32:
 119       case Intrinsic::memset_i64:
 120         M.getOrInsertFunction("memset", PointerType::get(Type::SByteTy),
 121                               PointerType::get(Type::SByteTy),
 122                               Type::IntTy, (--(--I->arg_end()))->getType(),
 123                               (Type *)0);
 124         break;
 125       case Intrinsic::isunordered_f32:
 126       case Intrinsic::isunordered_f64:
 127         EnsureFunctionExists(M, "isunordered", I->arg_begin(), I->arg_end(),
 128                              Type::BoolTy);
 129         break;
 130       case Intrinsic::sqrt_f32:
 131       case Intrinsic::sqrt_f64:
 132         if(I->arg_begin()->getType() == Type::FloatTy)
 133           EnsureFunctionExists(M, "sqrtf", I->arg_begin(), I->arg_end(),
 134                                Type::FloatTy);
 135         else
 136           EnsureFunctionExists(M, "sqrt", I->arg_begin(), I->arg_end(),
 137                                Type::DoubleTy);
 138         break;
 139       }
 140 }
 141
 142 /// LowerBSWAP - Emit the code to lower bswap of V before the specified
 143 /// instruction IP.
 144 static Value *LowerBSWAP(Value *V, Instruction *IP) {
 145   assert(V->getType()->isInteger() && "Can't bswap a non-integer type!");
 146
 147   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 148
 149   switch(BitSize) {
 150   default: assert(0 && "Unhandled type size of value to byteswap!");
 151   case 16: {
 152     Value *Tmp1 = new ShiftInst(Instruction::Shl, V,
 153                                 ConstantInt::get(Type::UByteTy,8),"bswap.2",IP);
 154     Value *Tmp2 = new ShiftInst(Instruction::LShr, V,
 155                                 ConstantInt::get(Type::UByteTy,8),"bswap.1",IP);
 156     V = BinaryOperator::createOr(Tmp1, Tmp2, "bswap.i16", IP);
 157     break;
 158   }
 159   case 32: {
 160     Value *Tmp4 = new ShiftInst(Instruction::Shl, V,
 161                               ConstantInt::get(Type::UByteTy,24),"bswap.4", IP);
 162     Value *Tmp3 = new ShiftInst(Instruction::Shl, V,
 163                               ConstantInt::get(Type::UByteTy,8),"bswap.3",IP);
 164     Value *Tmp2 = new ShiftInst(Instruction::LShr, V,
 165                               ConstantInt::get(Type::UByteTy,8),"bswap.2",IP);
 166     Value *Tmp1 = new ShiftInst(Instruction::LShr, V,
 167                               ConstantInt::get(Type::UByteTy,24),"bswap.1", IP);
 168     Tmp3 = BinaryOperator::createAnd(Tmp3,
 169                                      ConstantInt::get(Type::UIntTy, 0xFF0000),
 170                                      "bswap.and3", IP);
 171     Tmp2 = BinaryOperator::createAnd(Tmp2,
 172                                      ConstantInt::get(Type::UIntTy, 0xFF00),
 173                                      "bswap.and2", IP);
 174     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or1", IP);
 175     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or2", IP);
 176     V = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.i32", IP);
 177     break;
 178   }
 179   case 64: {
 180     Value *Tmp8 = new ShiftInst(Instruction::Shl, V,
 181                               ConstantInt::get(Type::UByteTy,56),"bswap.8", IP);
 182     Value *Tmp7 = new ShiftInst(Instruction::Shl, V,
 183                               ConstantInt::get(Type::UByteTy,40),"bswap.7", IP);
 184     Value *Tmp6 = new ShiftInst(Instruction::Shl, V,
 185                               ConstantInt::get(Type::UByteTy,24),"bswap.6", IP);
 186     Value *Tmp5 = new ShiftInst(Instruction::Shl, V,
 187                               ConstantInt::get(Type::UByteTy,8),"bswap.5", IP);
 188     Value* Tmp4 = new ShiftInst(Instruction::LShr, V,
 189                               ConstantInt::get(Type::UByteTy,8),"bswap.4", IP);
 190     Value* Tmp3 = new ShiftInst(Instruction::LShr, V,
 191                               ConstantInt::get(Type::UByteTy,24),"bswap.3", IP);
 192     Value* Tmp2 = new ShiftInst(Instruction::LShr, V,
 193                               ConstantInt::get(Type::UByteTy,40),"bswap.2", IP);
 194     Value* Tmp1 = new ShiftInst(Instruction::LShr, V,
 195                               ConstantInt::get(Type::UByteTy,56),"bswap.1", IP);
 196     Tmp7 = BinaryOperator::createAnd(Tmp7,
 197                              ConstantInt::get(Type::ULongTy,
 198                                0xFF000000000000ULL),
 199                              "bswap.and7", IP);
 200     Tmp6 = BinaryOperator::createAnd(Tmp6,
 201                              ConstantInt::get(Type::ULongTy, 0xFF0000000000ULL),
 202                              "bswap.and6", IP);
 203     Tmp5 = BinaryOperator::createAnd(Tmp5,
 204                              ConstantInt::get(Type::ULongTy, 0xFF00000000ULL),
 205                              "bswap.and5", IP);
 206     Tmp4 = BinaryOperator::createAnd(Tmp4,
 207                              ConstantInt::get(Type::ULongTy, 0xFF000000ULL),
 208                              "bswap.and4", IP);
 209     Tmp3 = BinaryOperator::createAnd(Tmp3,
 210                              ConstantInt::get(Type::ULongTy, 0xFF0000ULL),
 211                              "bswap.and3", IP);
 212     Tmp2 = BinaryOperator::createAnd(Tmp2,
 213                              ConstantInt::get(Type::ULongTy, 0xFF00ULL),
 214                              "bswap.and2", IP);
 215     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp7, "bswap.or1", IP);
 216     Tmp6 = BinaryOperator::createOr(Tmp6, Tmp5, "bswap.or2", IP);
 217     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or3", IP);
 218     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or4", IP);
 219     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp6, "bswap.or5", IP);
 220     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp2, "bswap.or6", IP);
 221     V = BinaryOperator::createOr(Tmp8, Tmp4, "bswap.i64", IP);
 222     break;
 223   }
 224   }
 225   return V;
 226 }
 227
 228 /// LowerCTPOP - Emit the code to lower ctpop of V before the specified
 229 /// instruction IP.
 230 static Value *LowerCTPOP(Value *V, Instruction *IP) {
 231   assert(V->getType()->isInteger() && "Can't ctpop a non-integer type!");
 232
 233   static const uint64_t MaskValues[6] = {
 234     0x5555555555555555ULL, 0x3333333333333333ULL,
 235     0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
 236     0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
 237   };
 238
 239   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 240
 241   for (unsigned i = 1, ct = 0; i != BitSize; i <<= 1, ++ct) {
 242     Value *MaskCst =
 243       ConstantExpr::getCast(ConstantInt::get(Type::ULongTy, MaskValues[ct]),
 244                                              V->getType());
 245     Value *LHS = BinaryOperator::createAnd(V, MaskCst, "cppop.and1", IP);
 246     Value *VShift = new ShiftInst(Instruction::LShr, V,
 247                       ConstantInt::get(Type::UByteTy, i), "ctpop.sh", IP);
 248     Value *RHS = BinaryOperator::createAnd(VShift, MaskCst, "cppop.and2", IP);
 249     V = BinaryOperator::createAdd(LHS, RHS, "ctpop.step", IP);
 250   }
 251
 252   return V;
 253 }
 254
 255 /// LowerCTLZ - Emit the code to lower ctlz of V before the specified
 256 /// instruction IP.
 257 static Value *LowerCTLZ(Value *V, Instruction *IP) {
 258
 259   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 260   for (unsigned i = 1; i != BitSize; i <<= 1) {
 261     Value *ShVal = ConstantInt::get(Type::UByteTy, i);
 262     ShVal = new ShiftInst(Instruction::LShr, V, ShVal, "ctlz.sh", IP);
 263     V = BinaryOperator::createOr(V, ShVal, "ctlz.step", IP);
 264   }
 265
 266   V = BinaryOperator::createNot(V, "", IP);
 267   return LowerCTPOP(V, IP);
 268 }
 269
 270
 271
 272 void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
 273   Function *Callee = CI->getCalledFunction();
 274   assert(Callee && "Cannot lower an indirect call!");
 275
 276   switch (Callee->getIntrinsicID()) {
 277   case Intrinsic::not_intrinsic:
 278     std::cerr << "Cannot lower a call to a non-intrinsic function '"
 279               << Callee->getName() << "'!\n";
 280     abort();
 281   default:
 282     std::cerr << "Error: Code generator does not support intrinsic function '"
 283               << Callee->getName() << "'!\n";
 284     abort();
 285
 286     // The setjmp/longjmp intrinsics should only exist in the code if it was
 287     // never optimized (ie, right out of the CFE), or if it has been hacked on
 288     // by the lowerinvoke pass.  In both cases, the right thing to do is to
 289     // convert the call to an explicit setjmp or longjmp call.
 290   case Intrinsic::setjmp: {
 291     static Function *SetjmpFCache = 0;
 292     static const unsigned castOpcodes[] = { Instruction::BitCast };
 293     Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(),
 294                                castOpcodes, Type::IntTy, SetjmpFCache);
 295     if (CI->getType() != Type::VoidTy)
 296       CI->replaceAllUsesWith(V);
 297     break;
 298   }
 299   case Intrinsic::sigsetjmp:
 300      if (CI->getType() != Type::VoidTy)
 301        CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 302      break;
 303
 304   case Intrinsic::longjmp: {
 305     static Function *LongjmpFCache = 0;
 306     static const unsigned castOpcodes[] =
 307       { Instruction::BitCast, 0 };
 308     ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(),
 309                     castOpcodes, Type::VoidTy, LongjmpFCache);
 310     break;
 311   }
 312
 313   case Intrinsic::siglongjmp: {
 314     // Insert the call to abort
 315     static Function *AbortFCache = 0;
 316     static const unsigned castOpcodes[] =
 317       { Instruction::BitCast, 0 };
 318     ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(),
 319                     castOpcodes, Type::VoidTy, AbortFCache);
 320     break;
 321   }
 322   case Intrinsic::ctpop_i8:
 323   case Intrinsic::ctpop_i16:
 324   case Intrinsic::ctpop_i32:
 325   case Intrinsic::ctpop_i64:
 326     CI->replaceAllUsesWith(LowerCTPOP(CI->getOperand(1), CI));
 327     break;
 328
 329   case Intrinsic::bswap_i16:
 330   case Intrinsic::bswap_i32:
 331   case Intrinsic::bswap_i64:
 332     CI->replaceAllUsesWith(LowerBSWAP(CI->getOperand(1), CI));
 333     break;
 334
 335   case Intrinsic::ctlz_i8:
 336   case Intrinsic::ctlz_i16:
 337   case Intrinsic::ctlz_i32:
 338   case Intrinsic::ctlz_i64:
 339     CI->replaceAllUsesWith(LowerCTLZ(CI->getOperand(1), CI));
 340     break;
 341
 342   case Intrinsic::cttz_i8:
 343   case Intrinsic::cttz_i16:
 344   case Intrinsic::cttz_i32:
 345   case Intrinsic::cttz_i64: {
 346     // cttz(x) -> ctpop(~X & (X-1))
 347     Value *Src = CI->getOperand(1);
 348     Value *NotSrc = BinaryOperator::createNot(Src, Src->getName()+".not", CI);
 349     Value *SrcM1  = ConstantInt::get(Src->getType(), 1);
 350     SrcM1 = BinaryOperator::createSub(Src, SrcM1, "", CI);
 351     Src = LowerCTPOP(BinaryOperator::createAnd(NotSrc, SrcM1, "", CI), CI);
 352     CI->replaceAllUsesWith(Src);
 353     break;
 354   }
 355
 356   case Intrinsic::stacksave:
 357   case Intrinsic::stackrestore: {
 358     static bool Warned = false;
 359     if (!Warned)
 360       std::cerr << "WARNING: this target does not support the llvm.stack"
 361        << (Callee->getIntrinsicID() == Intrinsic::stacksave ?
 362            "save" : "restore") << " intrinsic.\n";
 363     Warned = true;
 364     if (Callee->getIntrinsicID() == Intrinsic::stacksave)
 365       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 366     break;
 367   }
 368
 369   case Intrinsic::returnaddress:
 370   case Intrinsic::frameaddress:
 371     std::cerr << "WARNING: this target does not support the llvm."
 372               << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
 373                   "return" : "frame") << "address intrinsic.\n";
 374     CI->replaceAllUsesWith(ConstantPointerNull::get(
 375                                             cast<PointerType>(CI->getType())));
 376     break;
 377
 378   case Intrinsic::prefetch:
 379     break;    // Simply strip out prefetches on unsupported architectures
 380
 381   case Intrinsic::pcmarker:
 382     break;    // Simply strip out pcmarker on unsupported architectures
 383   case Intrinsic::readcyclecounter: {
 384     std::cerr << "WARNING: this target does not support the llvm.readcyclecoun"
 385               << "ter intrinsic.  It is being lowered to a constant 0\n";
 386     CI->replaceAllUsesWith(ConstantInt::get(Type::ULongTy, 0));
 387     break;
 388   }
 389
 390   case Intrinsic::dbg_stoppoint:
 391   case Intrinsic::dbg_region_start:
 392   case Intrinsic::dbg_region_end:
 393   case Intrinsic::dbg_func_start:
 394   case Intrinsic::dbg_declare:
 395     break;    // Simply strip out debugging intrinsics
 396
 397   case Intrinsic::memcpy_i32: {
 398     // The memcpy intrinsic take an extra alignment argument that the memcpy
 399     // libc function does not.
 400     static unsigned opcodes[] =
 401       { Instruction::BitCast, Instruction::BitCast, Instruction::BitCast };
 402     // FIXME:
 403     // if (target_is_64_bit) opcodes[2] = Instruction::ZExt;
 404     // else opcodes[2] = Instruction::BitCast;
 405     static Function *MemcpyFCache = 0;
 406     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
 407                     opcodes, (*(CI->op_begin()+1))->getType(), MemcpyFCache);
 408     break;
 409   }
 410   case Intrinsic::memcpy_i64: {
 411     static unsigned opcodes[] =
 412       { Instruction::BitCast, Instruction::BitCast, Instruction::Trunc };
 413     // FIXME:
 414     // if (target_is_64_bit) opcodes[2] = Instruction::BitCast;
 415     // else opcodes[2] = Instruction::Trunc;
 416     static Function *MemcpyFCache = 0;
 417     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
 418                      opcodes, (*(CI->op_begin()+1))->getType(), MemcpyFCache);
 419     break;
 420   }
 421   case Intrinsic::memmove_i32: {
 422     // The memmove intrinsic take an extra alignment argument that the memmove
 423     // libc function does not.
 424     static unsigned opcodes[] =
 425       { Instruction::BitCast, Instruction::BitCast, Instruction::BitCast };
 426     // FIXME:
 427     // if (target_is_64_bit) opcodes[2] = Instruction::ZExt;
 428     // else opcodes[2] = Instruction::BitCast;
 429     static Function *MemmoveFCache = 0;
 430     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
 431                     opcodes, (*(CI->op_begin()+1))->getType(), MemmoveFCache);
 432     break;
 433   }
 434   case Intrinsic::memmove_i64: {
 435     // The memmove intrinsic take an extra alignment argument that the memmove
 436     // libc function does not.
 437     static const unsigned opcodes[] =
 438       { Instruction::BitCast, Instruction::BitCast, Instruction::Trunc };
 439     // if (target_is_64_bit) opcodes[2] = Instruction::BitCast;
 440     // else opcodes[2] = Instruction::Trunc;
 441     static Function *MemmoveFCache = 0;
 442     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
 443                     opcodes, (*(CI->op_begin()+1))->getType(), MemmoveFCache);
 444     break;
 445   }
 446   case Intrinsic::memset_i32: {
 447     // The memset intrinsic take an extra alignment argument that the memset
 448     // libc function does not.
 449     static const unsigned opcodes[] =
 450       { Instruction::BitCast, Instruction::ZExt, Instruction::ZExt, 0 };
 451     // if (target_is_64_bit) opcodes[2] = Instruction::BitCast;
 452     // else opcodes[2] = Instruction::ZExt;
 453     static Function *MemsetFCache = 0;
 454     ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
 455                     opcodes, (*(CI->op_begin()+1))->getType(), MemsetFCache);
 456   }
 457   case Intrinsic::memset_i64: {
 458     // The memset intrinsic take an extra alignment argument that the memset
 459     // libc function does not.
 460     static const unsigned opcodes[] =
 461       { Instruction::BitCast, Instruction::ZExt, Instruction::Trunc, 0 };
 462     // if (target_is_64_bit) opcodes[2] = Instruction::BitCast;
 463     // else opcodes[2] = Instruction::Trunc;
 464     static Function *MemsetFCache = 0;
 465     ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
 466                     opcodes, (*(CI->op_begin()+1))->getType(), MemsetFCache);
 467     break;
 468   }
 469   case Intrinsic::isunordered_f32:
 470   case Intrinsic::isunordered_f64: {
 471     Value *L = CI->getOperand(1);
 472     Value *R = CI->getOperand(2);
 473
 474     Value *LIsNan = new SetCondInst(Instruction::SetNE, L, L, "LIsNan", CI);
 475     Value *RIsNan = new SetCondInst(Instruction::SetNE, R, R, "RIsNan", CI);
 476     CI->replaceAllUsesWith(
 477       BinaryOperator::create(Instruction::Or, LIsNan, RIsNan,
 478                              "isunordered", CI));
 479     break;
 480   }
 481   case Intrinsic::sqrt_f32: {
 482     static const unsigned opcodes[] = { 0 };
 483     static Function *sqrtfFCache = 0;
 484     ReplaceCallWith("sqrtf", CI, CI->op_begin()+1, CI->op_end(),
 485                     opcodes, Type::FloatTy, sqrtfFCache);
 486     break;
 487   }
 488   case Intrinsic::sqrt_f64: {
 489     static const unsigned opcodes[] =  { 0 };
 490     static Function *sqrtFCache = 0;
 491     ReplaceCallWith("sqrt", CI, CI->op_begin()+1, CI->op_end(),
 492                     opcodes, Type::DoubleTy, sqrtFCache);
 493     break;
 494   }
 495   }
 496
 497   assert(CI->use_empty() &&
 498          "Lowering should have eliminated any uses of the intrinsic call!");
 499   CI->eraseFromParent();
 500 }