lib/CodeGen/IntrinsicLowering.cpp

   1 //===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // 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/ADT/SmallVector.h"
  16 #include "llvm/IR/CallSite.h"
  17 #include "llvm/IR/Constants.h"
  18 #include "llvm/IR/DataLayout.h"
  19 #include "llvm/IR/DerivedTypes.h"
  20 #include "llvm/IR/IRBuilder.h"
  21 #include "llvm/IR/Module.h"
  22 #include "llvm/IR/Type.h"
  23 #include "llvm/Support/ErrorHandling.h"
  24 #include "llvm/Support/raw_ostream.h"
  25 using namespace llvm;
  26
  27 template <class ArgIt>
  28 static void EnsureFunctionExists(Module &M, const char *Name,
  29                                  ArgIt ArgBegin, ArgIt ArgEnd,
  30                                  Type *RetTy) {
  31   // Insert a correctly-typed definition now.
  32   std::vector<Type *> ParamTys;
  33   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  34     ParamTys.push_back(I->getType());
  35   M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
  36 }
  37
  38 static void EnsureFPIntrinsicsExist(Module &M, Function &Fn,
  39                                     const char *FName,
  40                                     const char *DName, const char *LDName) {
  41   // Insert definitions for all the floating point types.
  42   switch((int)Fn.arg_begin()->getType()->getTypeID()) {
  43   case Type::FloatTyID:
  44     EnsureFunctionExists(M, FName, Fn.arg_begin(), Fn.arg_end(),
  45                          Type::getFloatTy(M.getContext()));
  46     break;
  47   case Type::DoubleTyID:
  48     EnsureFunctionExists(M, DName, Fn.arg_begin(), Fn.arg_end(),
  49                          Type::getDoubleTy(M.getContext()));
  50     break;
  51   case Type::X86_FP80TyID:
  52   case Type::FP128TyID:
  53   case Type::PPC_FP128TyID:
  54     EnsureFunctionExists(M, LDName, Fn.arg_begin(), Fn.arg_end(),
  55                          Fn.arg_begin()->getType());
  56     break;
  57   }
  58 }
  59
  60 /// This function is used when we want to lower an intrinsic call to a call of
  61 /// an external function. This handles hard cases such as when there was already
  62 /// a prototype for the external function, but that prototype doesn't match the
  63 /// arguments we expect to pass in.
  64 template <class ArgIt>
  65 static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
  66                                  ArgIt ArgBegin, ArgIt ArgEnd,
  67                                  Type *RetTy) {
  68   // If we haven't already looked up this function, check to see if the
  69   // program already contains a function with this name.
  70   Module *M = CI->getModule();
  71   // Get or insert the definition now.
  72   std::vector<Type *> ParamTys;
  73   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  74     ParamTys.push_back((*I)->getType());
  75   Constant* FCache = M->getOrInsertFunction(NewFn,
  76                                   FunctionType::get(RetTy, ParamTys, false));
  77
  78   IRBuilder<> Builder(CI->getParent(), CI->getIterator());
  79   SmallVector<Value *, 8> Args(ArgBegin, ArgEnd);
  80   CallInst *NewCI = Builder.CreateCall(FCache, Args);
  81   NewCI->setName(CI->getName());
  82   if (!CI->use_empty())
  83     CI->replaceAllUsesWith(NewCI);
  84   return NewCI;
  85 }
  86
  87 // VisualStudio defines setjmp as _setjmp
  88 #if defined(_MSC_VER) && defined(setjmp) && \
  89                          !defined(setjmp_undefined_for_msvc)
  90 #  pragma push_macro("setjmp")
  91 #  undef setjmp
  92 #  define setjmp_undefined_for_msvc
  93 #endif
  94
  95 void IntrinsicLowering::AddPrototypes(Module &M) {
  96   LLVMContext &Context = M.getContext();
  97   for (auto &F : M)
  98     if (F.isDeclaration() && !F.use_empty())
  99       switch (F.getIntrinsicID()) {
 100       default: break;
 101       case Intrinsic::setjmp:
 102         EnsureFunctionExists(M, "setjmp", F.arg_begin(), F.arg_end(),
 103                              Type::getInt32Ty(M.getContext()));
 104         break;
 105       case Intrinsic::longjmp:
 106         EnsureFunctionExists(M, "longjmp", F.arg_begin(), F.arg_end(),
 107                              Type::getVoidTy(M.getContext()));
 108         break;
 109       case Intrinsic::siglongjmp:
 110         EnsureFunctionExists(M, "abort", F.arg_end(), F.arg_end(),
 111                              Type::getVoidTy(M.getContext()));
 112         break;
 113       case Intrinsic::memcpy:
 114         M.getOrInsertFunction("memcpy",
 115           Type::getInt8PtrTy(Context),
 116                               Type::getInt8PtrTy(Context),
 117                               Type::getInt8PtrTy(Context),
 118                               DL.getIntPtrType(Context));
 119         break;
 120       case Intrinsic::memmove:
 121         M.getOrInsertFunction("memmove",
 122           Type::getInt8PtrTy(Context),
 123                               Type::getInt8PtrTy(Context),
 124                               Type::getInt8PtrTy(Context),
 125                               DL.getIntPtrType(Context));
 126         break;
 127       case Intrinsic::memset:
 128         M.getOrInsertFunction("memset",
 129           Type::getInt8PtrTy(Context),
 130                               Type::getInt8PtrTy(Context),
 131                               Type::getInt32Ty(M.getContext()),
 132                               DL.getIntPtrType(Context));
 133         break;
 134       case Intrinsic::sqrt:
 135         EnsureFPIntrinsicsExist(M, F, "sqrtf", "sqrt", "sqrtl");
 136         break;
 137       case Intrinsic::sin:
 138         EnsureFPIntrinsicsExist(M, F, "sinf", "sin", "sinl");
 139         break;
 140       case Intrinsic::cos:
 141         EnsureFPIntrinsicsExist(M, F, "cosf", "cos", "cosl");
 142         break;
 143       case Intrinsic::pow:
 144         EnsureFPIntrinsicsExist(M, F, "powf", "pow", "powl");
 145         break;
 146       case Intrinsic::log:
 147         EnsureFPIntrinsicsExist(M, F, "logf", "log", "logl");
 148         break;
 149       case Intrinsic::log2:
 150         EnsureFPIntrinsicsExist(M, F, "log2f", "log2", "log2l");
 151         break;
 152       case Intrinsic::log10:
 153         EnsureFPIntrinsicsExist(M, F, "log10f", "log10", "log10l");
 154         break;
 155       case Intrinsic::exp:
 156         EnsureFPIntrinsicsExist(M, F, "expf", "exp", "expl");
 157         break;
 158       case Intrinsic::exp2:
 159         EnsureFPIntrinsicsExist(M, F, "exp2f", "exp2", "exp2l");
 160         break;
 161       }
 162 }
 163
 164 /// Emit the code to lower bswap of V before the specified instruction IP.
 165 static Value *LowerBSWAP(LLVMContext &Context, Value *V, Instruction *IP) {
 166   assert(V->getType()->isIntOrIntVectorTy() && "Can't bswap a non-integer type!");
 167
 168   unsigned BitSize = V->getType()->getScalarSizeInBits();
 169
 170   IRBuilder<> Builder(IP);
 171
 172   switch(BitSize) {
 173   default: llvm_unreachable("Unhandled type size of value to byteswap!");
 174   case 16: {
 175     Value *Tmp1 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
 176                                     "bswap.2");
 177     Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
 178                                      "bswap.1");
 179     V = Builder.CreateOr(Tmp1, Tmp2, "bswap.i16");
 180     break;
 181   }
 182   case 32: {
 183     Value *Tmp4 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
 184                                     "bswap.4");
 185     Value *Tmp3 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
 186                                     "bswap.3");
 187     Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
 188                                      "bswap.2");
 189     Value *Tmp1 = Builder.CreateLShr(V,ConstantInt::get(V->getType(), 24),
 190                                      "bswap.1");
 191     Tmp3 = Builder.CreateAnd(Tmp3,
 192                          ConstantInt::get(V->getType(), 0xFF0000),
 193                              "bswap.and3");
 194     Tmp2 = Builder.CreateAnd(Tmp2,
 195                            ConstantInt::get(V->getType(), 0xFF00),
 196                              "bswap.and2");
 197     Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or1");
 198     Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or2");
 199     V = Builder.CreateOr(Tmp4, Tmp2, "bswap.i32");
 200     break;
 201   }
 202   case 64: {
 203     Value *Tmp8 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 56),
 204                                     "bswap.8");
 205     Value *Tmp7 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 40),
 206                                     "bswap.7");
 207     Value *Tmp6 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
 208                                     "bswap.6");
 209     Value *Tmp5 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
 210                                     "bswap.5");
 211     Value* Tmp4 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
 212                                      "bswap.4");
 213     Value* Tmp3 = Builder.CreateLShr(V,
 214                                      ConstantInt::get(V->getType(), 24),
 215                                      "bswap.3");
 216     Value* Tmp2 = Builder.CreateLShr(V,
 217                                      ConstantInt::get(V->getType(), 40),
 218                                      "bswap.2");
 219     Value* Tmp1 = Builder.CreateLShr(V,
 220                                      ConstantInt::get(V->getType(), 56),
 221                                      "bswap.1");
 222     Tmp7 = Builder.CreateAnd(Tmp7,
 223                              ConstantInt::get(V->getType(),
 224                                               0xFF000000000000ULL),
 225                              "bswap.and7");
 226     Tmp6 = Builder.CreateAnd(Tmp6,
 227                              ConstantInt::get(V->getType(),
 228                                               0xFF0000000000ULL),
 229                              "bswap.and6");
 230     Tmp5 = Builder.CreateAnd(Tmp5,
 231                         ConstantInt::get(V->getType(),
 232                              0xFF00000000ULL),
 233                              "bswap.and5");
 234     Tmp4 = Builder.CreateAnd(Tmp4,
 235                         ConstantInt::get(V->getType(),
 236                              0xFF000000ULL),
 237                              "bswap.and4");
 238     Tmp3 = Builder.CreateAnd(Tmp3,
 239                              ConstantInt::get(V->getType(),
 240                              0xFF0000ULL),
 241                              "bswap.and3");
 242     Tmp2 = Builder.CreateAnd(Tmp2,
 243                              ConstantInt::get(V->getType(),
 244                              0xFF00ULL),
 245                              "bswap.and2");
 246     Tmp8 = Builder.CreateOr(Tmp8, Tmp7, "bswap.or1");
 247     Tmp6 = Builder.CreateOr(Tmp6, Tmp5, "bswap.or2");
 248     Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or3");
 249     Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or4");
 250     Tmp8 = Builder.CreateOr(Tmp8, Tmp6, "bswap.or5");
 251     Tmp4 = Builder.CreateOr(Tmp4, Tmp2, "bswap.or6");
 252     V = Builder.CreateOr(Tmp8, Tmp4, "bswap.i64");
 253     break;
 254   }
 255   }
 256   return V;
 257 }
 258
 259 /// Emit the code to lower ctpop of V before the specified instruction IP.
 260 static Value *LowerCTPOP(LLVMContext &Context, Value *V, Instruction *IP) {
 261   assert(V->getType()->isIntegerTy() && "Can't ctpop a non-integer type!");
 262
 263   static const uint64_t MaskValues[6] = {
 264     0x5555555555555555ULL, 0x3333333333333333ULL,
 265     0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
 266     0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
 267   };
 268
 269   IRBuilder<> Builder(IP);
 270
 271   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 272   unsigned WordSize = (BitSize + 63) / 64;
 273   Value *Count = ConstantInt::get(V->getType(), 0);
 274
 275   for (unsigned n = 0; n < WordSize; ++n) {
 276     Value *PartValue = V;
 277     for (unsigned i = 1, ct = 0; i < (BitSize>64 ? 64 : BitSize);
 278          i <<= 1, ++ct) {
 279       Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]);
 280       Value *LHS = Builder.CreateAnd(PartValue, MaskCst, "cppop.and1");
 281       Value *VShift = Builder.CreateLShr(PartValue,
 282                                         ConstantInt::get(V->getType(), i),
 283                                          "ctpop.sh");
 284       Value *RHS = Builder.CreateAnd(VShift, MaskCst, "cppop.and2");
 285       PartValue = Builder.CreateAdd(LHS, RHS, "ctpop.step");
 286     }
 287     Count = Builder.CreateAdd(PartValue, Count, "ctpop.part");
 288     if (BitSize > 64) {
 289       V = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 64),
 290                              "ctpop.part.sh");
 291       BitSize -= 64;
 292     }
 293   }
 294
 295   return Count;
 296 }
 297
 298 /// Emit the code to lower ctlz of V before the specified instruction IP.
 299 static Value *LowerCTLZ(LLVMContext &Context, Value *V, Instruction *IP) {
 300
 301   IRBuilder<> Builder(IP);
 302
 303   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 304   for (unsigned i = 1; i < BitSize; i <<= 1) {
 305     Value *ShVal = ConstantInt::get(V->getType(), i);
 306     ShVal = Builder.CreateLShr(V, ShVal, "ctlz.sh");
 307     V = Builder.CreateOr(V, ShVal, "ctlz.step");
 308   }
 309
 310   V = Builder.CreateNot(V);
 311   return LowerCTPOP(Context, V, IP);
 312 }
 313
 314 static void ReplaceFPIntrinsicWithCall(CallInst *CI, const char *Fname,
 315                                        const char *Dname,
 316                                        const char *LDname) {
 317   CallSite CS(CI);
 318   switch (CI->getArgOperand(0)->getType()->getTypeID()) {
 319   default: llvm_unreachable("Invalid type in intrinsic");
 320   case Type::FloatTyID:
 321     ReplaceCallWith(Fname, CI, CS.arg_begin(), CS.arg_end(),
 322                   Type::getFloatTy(CI->getContext()));
 323     break;
 324   case Type::DoubleTyID:
 325     ReplaceCallWith(Dname, CI, CS.arg_begin(), CS.arg_end(),
 326                   Type::getDoubleTy(CI->getContext()));
 327     break;
 328   case Type::X86_FP80TyID:
 329   case Type::FP128TyID:
 330   case Type::PPC_FP128TyID:
 331     ReplaceCallWith(LDname, CI, CS.arg_begin(), CS.arg_end(),
 332                   CI->getArgOperand(0)->getType());
 333     break;
 334   }
 335 }
 336
 337 void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
 338   IRBuilder<> Builder(CI);
 339   LLVMContext &Context = CI->getContext();
 340
 341   const Function *Callee = CI->getCalledFunction();
 342   assert(Callee && "Cannot lower an indirect call!");
 343
 344   CallSite CS(CI);
 345   switch (Callee->getIntrinsicID()) {
 346   case Intrinsic::not_intrinsic:
 347     report_fatal_error("Cannot lower a call to a non-intrinsic function '"+
 348                       Callee->getName() + "'!");
 349   default:
 350     report_fatal_error("Code generator does not support intrinsic function '"+
 351                       Callee->getName()+"'!");
 352
 353   case Intrinsic::expect: {
 354     // Just replace __builtin_expect(exp, c) with EXP.
 355     Value *V = CI->getArgOperand(0);
 356     CI->replaceAllUsesWith(V);
 357     break;
 358   }
 359
 360     // The setjmp/longjmp intrinsics should only exist in the code if it was
 361     // never optimized (ie, right out of the CFE), or if it has been hacked on
 362     // by the lowerinvoke pass.  In both cases, the right thing to do is to
 363     // convert the call to an explicit setjmp or longjmp call.
 364   case Intrinsic::setjmp: {
 365     Value *V = ReplaceCallWith("setjmp", CI, CS.arg_begin(), CS.arg_end(),
 366                                Type::getInt32Ty(Context));
 367     if (!CI->getType()->isVoidTy())
 368       CI->replaceAllUsesWith(V);
 369     break;
 370   }
 371   case Intrinsic::sigsetjmp:
 372      if (!CI->getType()->isVoidTy())
 373        CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 374      break;
 375
 376   case Intrinsic::longjmp: {
 377     ReplaceCallWith("longjmp", CI, CS.arg_begin(), CS.arg_end(),
 378                     Type::getVoidTy(Context));
 379     break;
 380   }
 381
 382   case Intrinsic::siglongjmp: {
 383     // Insert the call to abort
 384     ReplaceCallWith("abort", CI, CS.arg_end(), CS.arg_end(),
 385                     Type::getVoidTy(Context));
 386     break;
 387   }
 388   case Intrinsic::ctpop:
 389     CI->replaceAllUsesWith(LowerCTPOP(Context, CI->getArgOperand(0), CI));
 390     break;
 391
 392   case Intrinsic::bswap:
 393     CI->replaceAllUsesWith(LowerBSWAP(Context, CI->getArgOperand(0), CI));
 394     break;
 395
 396   case Intrinsic::ctlz:
 397     CI->replaceAllUsesWith(LowerCTLZ(Context, CI->getArgOperand(0), CI));
 398     break;
 399
 400   case Intrinsic::cttz: {
 401     // cttz(x) -> ctpop(~X & (X-1))
 402     Value *Src = CI->getArgOperand(0);
 403     Value *NotSrc = Builder.CreateNot(Src);
 404     NotSrc->setName(Src->getName() + ".not");
 405     Value *SrcM1 = ConstantInt::get(Src->getType(), 1);
 406     SrcM1 = Builder.CreateSub(Src, SrcM1);
 407     Src = LowerCTPOP(Context, Builder.CreateAnd(NotSrc, SrcM1), CI);
 408     CI->replaceAllUsesWith(Src);
 409     break;
 410   }
 411
 412   case Intrinsic::stacksave:
 413   case Intrinsic::stackrestore: {
 414     if (!Warned)
 415       errs() << "WARNING: this target does not support the llvm.stack"
 416              << (Callee->getIntrinsicID() == Intrinsic::stacksave ?
 417                "save" : "restore") << " intrinsic.\n";
 418     Warned = true;
 419     if (Callee->getIntrinsicID() == Intrinsic::stacksave)
 420       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 421     break;
 422   }
 423
 424   case Intrinsic::get_dynamic_area_offset:
 425     errs() << "WARNING: this target does not support the custom llvm.get."
 426               "dynamic.area.offset.  It is being lowered to a constant 0\n";
 427     // Just lower it to a constant 0 because for most targets
 428     // @llvm.get.dynamic.area.offset is lowered to zero.
 429     CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 0));
 430     break;
 431   case Intrinsic::returnaddress:
 432   case Intrinsic::frameaddress:
 433     errs() << "WARNING: this target does not support the llvm."
 434            << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
 435              "return" : "frame") << "address intrinsic.\n";
 436     CI->replaceAllUsesWith(
 437         ConstantPointerNull::get(cast<PointerType>(CI->getType())));
 438     break;
 439   case Intrinsic::addressofreturnaddress:
 440     errs() << "WARNING: this target does not support the "
 441               "llvm.addressofreturnaddress intrinsic.\n";
 442     CI->replaceAllUsesWith(
 443         ConstantPointerNull::get(cast<PointerType>(CI->getType())));
 444     break;
 445
 446   case Intrinsic::prefetch:
 447     break;    // Simply strip out prefetches on unsupported architectures
 448
 449   case Intrinsic::pcmarker:
 450     break;    // Simply strip out pcmarker on unsupported architectures
 451   case Intrinsic::readcyclecounter: {
 452     errs() << "WARNING: this target does not support the llvm.readcyclecoun"
 453            << "ter intrinsic.  It is being lowered to a constant 0\n";
 454     CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0));
 455     break;
 456   }
 457
 458   case Intrinsic::dbg_declare:
 459   case Intrinsic::dbg_label:
 460     break;    // Simply strip out debugging intrinsics
 461
 462   case Intrinsic::eh_typeid_for:
 463     // Return something different to eh_selector.
 464     CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
 465     break;
 466
 467   case Intrinsic::annotation:
 468   case Intrinsic::ptr_annotation:
 469     // Just drop the annotation, but forward the value
 470     CI->replaceAllUsesWith(CI->getOperand(0));
 471     break;
 472
 473   case Intrinsic::assume:
 474   case Intrinsic::var_annotation:
 475     break;   // Strip out these intrinsics
 476
 477   case Intrinsic::memcpy: {
 478     Type *IntPtr = DL.getIntPtrType(Context);
 479     Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
 480                                         /* isSigned */ false);
 481     Value *Ops[3];
 482     Ops[0] = CI->getArgOperand(0);
 483     Ops[1] = CI->getArgOperand(1);
 484     Ops[2] = Size;
 485     ReplaceCallWith("memcpy", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
 486     break;
 487   }
 488   case Intrinsic::memmove: {
 489     Type *IntPtr = DL.getIntPtrType(Context);
 490     Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
 491                                         /* isSigned */ false);
 492     Value *Ops[3];
 493     Ops[0] = CI->getArgOperand(0);
 494     Ops[1] = CI->getArgOperand(1);
 495     Ops[2] = Size;
 496     ReplaceCallWith("memmove", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
 497     break;
 498   }
 499   case Intrinsic::memset: {
 500     Value *Op0 = CI->getArgOperand(0);
 501     Type *IntPtr = DL.getIntPtrType(Op0->getType());
 502     Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
 503                                         /* isSigned */ false);
 504     Value *Ops[3];
 505     Ops[0] = Op0;
 506     // Extend the amount to i32.
 507     Ops[1] = Builder.CreateIntCast(CI->getArgOperand(1),
 508                                    Type::getInt32Ty(Context),
 509                                    /* isSigned */ false);
 510     Ops[2] = Size;
 511     ReplaceCallWith("memset", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
 512     break;
 513   }
 514   case Intrinsic::sqrt: {
 515     ReplaceFPIntrinsicWithCall(CI, "sqrtf", "sqrt", "sqrtl");
 516     break;
 517   }
 518   case Intrinsic::log: {
 519     ReplaceFPIntrinsicWithCall(CI, "logf", "log", "logl");
 520     break;
 521   }
 522   case Intrinsic::log2: {
 523     ReplaceFPIntrinsicWithCall(CI, "log2f", "log2", "log2l");
 524     break;
 525   }
 526   case Intrinsic::log10: {
 527     ReplaceFPIntrinsicWithCall(CI, "log10f", "log10", "log10l");
 528     break;
 529   }
 530   case Intrinsic::exp: {
 531     ReplaceFPIntrinsicWithCall(CI, "expf", "exp", "expl");
 532     break;
 533   }
 534   case Intrinsic::exp2: {
 535     ReplaceFPIntrinsicWithCall(CI, "exp2f", "exp2", "exp2l");
 536     break;
 537   }
 538   case Intrinsic::pow: {
 539     ReplaceFPIntrinsicWithCall(CI, "powf", "pow", "powl");
 540     break;
 541   }
 542   case Intrinsic::sin: {
 543     ReplaceFPIntrinsicWithCall(CI, "sinf", "sin", "sinl");
 544     break;
 545   }
 546   case Intrinsic::cos: {
 547     ReplaceFPIntrinsicWithCall(CI, "cosf", "cos", "cosl");
 548     break;
 549   }
 550   case Intrinsic::floor: {
 551     ReplaceFPIntrinsicWithCall(CI, "floorf", "floor", "floorl");
 552     break;
 553   }
 554   case Intrinsic::ceil: {
 555     ReplaceFPIntrinsicWithCall(CI, "ceilf", "ceil", "ceill");
 556     break;
 557   }
 558   case Intrinsic::trunc: {
 559     ReplaceFPIntrinsicWithCall(CI, "truncf", "trunc", "truncl");
 560     break;
 561   }
 562   case Intrinsic::round: {
 563     ReplaceFPIntrinsicWithCall(CI, "roundf", "round", "roundl");
 564     break;
 565   }
 566   case Intrinsic::copysign: {
 567     ReplaceFPIntrinsicWithCall(CI, "copysignf", "copysign", "copysignl");
 568     break;
 569   }
 570   case Intrinsic::flt_rounds:
 571      // Lower to "round to the nearest"
 572      if (!CI->getType()->isVoidTy())
 573        CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
 574      break;
 575   case Intrinsic::invariant_start:
 576   case Intrinsic::lifetime_start:
 577     // Discard region information.
 578     CI->replaceAllUsesWith(UndefValue::get(CI->getType()));
 579     break;
 580   case Intrinsic::invariant_end:
 581   case Intrinsic::lifetime_end:
 582     // Discard region information.
 583     break;
 584   }
 585
 586   assert(CI->use_empty() &&
 587          "Lowering should have eliminated any uses of the intrinsic call!");
 588   CI->eraseFromParent();
 589 }
 590
 591 bool IntrinsicLowering::LowerToByteSwap(CallInst *CI) {
 592   // Verify this is a simple bswap.
 593   if (CI->getNumArgOperands() != 1 ||
 594       CI->getType() != CI->getArgOperand(0)->getType() ||
 595       !CI->getType()->isIntegerTy())
 596     return false;
 597
 598   IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 599   if (!Ty)
 600     return false;
 601
 602   // Okay, we can do this xform, do so now.
 603   Module *M = CI->getModule();
 604   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Ty);
 605
 606   Value *Op = CI->getArgOperand(0);
 607   Op = CallInst::Create(Int, Op, CI->getName(), CI);
 608
 609   CI->replaceAllUsesWith(Op);
 610   CI->eraseFromParent();
 611   return true;
 612 }