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/Constants.h" 17 #include "llvm/IR/DataLayout.h" 18 #include "llvm/IR/DerivedTypes.h" 19 #include "llvm/IR/IRBuilder.h" 20 #include "llvm/IR/Module.h" 21 #include "llvm/IR/Type.h" 22 #include "llvm/Support/CallSite.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 /// ReplaceCallWith - This function is used when we want to lower an intrinsic 61 /// call to a call of an external function. This handles hard cases such as 62 /// when there was already a prototype for the external function, and if that 63 /// prototype doesn't match the 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->getParent()->getParent()->getParent(); 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); 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 (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 98 if (I->isDeclaration() && !I->use_empty()) 99 switch (I->getIntrinsicID()) { 100 default: break; 101 case Intrinsic::setjmp: 102 EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(), 103 Type::getInt32Ty(M.getContext())); 104 break; 105 case Intrinsic::longjmp: 106 EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(), 107 Type::getVoidTy(M.getContext())); 108 break; 109 case Intrinsic::siglongjmp: 110 EnsureFunctionExists(M, "abort", I->arg_end(), I->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 TD.getIntPtrType(Context), (Type *)0); 119 break; 120 case Intrinsic::memmove: 121 M.getOrInsertFunction("memmove", 122 Type::getInt8PtrTy(Context), 123 Type::getInt8PtrTy(Context), 124 Type::getInt8PtrTy(Context), 125 TD.getIntPtrType(Context), (Type *)0); 126 break; 127 case Intrinsic::memset: 128 M.getOrInsertFunction("memset", 129 Type::getInt8PtrTy(Context), 130 Type::getInt8PtrTy(Context), 131 Type::getInt32Ty(M.getContext()), 132 TD.getIntPtrType(Context), (Type *)0); 133 break; 134 case Intrinsic::sqrt: 135 EnsureFPIntrinsicsExist(M, I, "sqrtf", "sqrt", "sqrtl"); 136 break; 137 case Intrinsic::sin: 138 EnsureFPIntrinsicsExist(M, I, "sinf", "sin", "sinl"); 139 break; 140 case Intrinsic::cos: 141 EnsureFPIntrinsicsExist(M, I, "cosf", "cos", "cosl"); 142 break; 143 case Intrinsic::pow: 144 EnsureFPIntrinsicsExist(M, I, "powf", "pow", "powl"); 145 break; 146 case Intrinsic::log: 147 EnsureFPIntrinsicsExist(M, I, "logf", "log", "logl"); 148 break; 149 case Intrinsic::log2: 150 EnsureFPIntrinsicsExist(M, I, "log2f", "log2", "log2l"); 151 break; 152 case Intrinsic::log10: 153 EnsureFPIntrinsicsExist(M, I, "log10f", "log10", "log10l"); 154 break; 155 case Intrinsic::exp: 156 EnsureFPIntrinsicsExist(M, I, "expf", "exp", "expl"); 157 break; 158 case Intrinsic::exp2: 159 EnsureFPIntrinsicsExist(M, I, "exp2f", "exp2", "exp2l"); 160 break; 161 } 162 } 163 164 /// LowerBSWAP - Emit the code to lower bswap of V before the specified 165 /// instruction IP. 166 static Value *LowerBSWAP(LLVMContext &Context, Value *V, Instruction *IP) { 167 assert(V->getType()->isIntegerTy() && "Can't bswap a non-integer type!"); 168 169 unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); 170 171 IRBuilder<> Builder(IP->getParent(), IP); 172 173 switch(BitSize) { 174 default: llvm_unreachable("Unhandled type size of value to byteswap!"); 175 case 16: { 176 Value *Tmp1 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8), 177 "bswap.2"); 178 Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8), 179 "bswap.1"); 180 V = Builder.CreateOr(Tmp1, Tmp2, "bswap.i16"); 181 break; 182 } 183 case 32: { 184 Value *Tmp4 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24), 185 "bswap.4"); 186 Value *Tmp3 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8), 187 "bswap.3"); 188 Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8), 189 "bswap.2"); 190 Value *Tmp1 = Builder.CreateLShr(V,ConstantInt::get(V->getType(), 24), 191 "bswap.1"); 192 Tmp3 = Builder.CreateAnd(Tmp3, 193 ConstantInt::get(Type::getInt32Ty(Context), 0xFF0000), 194 "bswap.and3"); 195 Tmp2 = Builder.CreateAnd(Tmp2, 196 ConstantInt::get(Type::getInt32Ty(Context), 0xFF00), 197 "bswap.and2"); 198 Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or1"); 199 Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or2"); 200 V = Builder.CreateOr(Tmp4, Tmp2, "bswap.i32"); 201 break; 202 } 203 case 64: { 204 Value *Tmp8 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 56), 205 "bswap.8"); 206 Value *Tmp7 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 40), 207 "bswap.7"); 208 Value *Tmp6 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24), 209 "bswap.6"); 210 Value *Tmp5 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8), 211 "bswap.5"); 212 Value* Tmp4 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8), 213 "bswap.4"); 214 Value* Tmp3 = Builder.CreateLShr(V, 215 ConstantInt::get(V->getType(), 24), 216 "bswap.3"); 217 Value* Tmp2 = Builder.CreateLShr(V, 218 ConstantInt::get(V->getType(), 40), 219 "bswap.2"); 220 Value* Tmp1 = Builder.CreateLShr(V, 221 ConstantInt::get(V->getType(), 56), 222 "bswap.1"); 223 Tmp7 = Builder.CreateAnd(Tmp7, 224 ConstantInt::get(Type::getInt64Ty(Context), 225 0xFF000000000000ULL), 226 "bswap.and7"); 227 Tmp6 = Builder.CreateAnd(Tmp6, 228 ConstantInt::get(Type::getInt64Ty(Context), 229 0xFF0000000000ULL), 230 "bswap.and6"); 231 Tmp5 = Builder.CreateAnd(Tmp5, 232 ConstantInt::get(Type::getInt64Ty(Context), 233 0xFF00000000ULL), 234 "bswap.and5"); 235 Tmp4 = Builder.CreateAnd(Tmp4, 236 ConstantInt::get(Type::getInt64Ty(Context), 237 0xFF000000ULL), 238 "bswap.and4"); 239 Tmp3 = Builder.CreateAnd(Tmp3, 240 ConstantInt::get(Type::getInt64Ty(Context), 241 0xFF0000ULL), 242 "bswap.and3"); 243 Tmp2 = Builder.CreateAnd(Tmp2, 244 ConstantInt::get(Type::getInt64Ty(Context), 245 0xFF00ULL), 246 "bswap.and2"); 247 Tmp8 = Builder.CreateOr(Tmp8, Tmp7, "bswap.or1"); 248 Tmp6 = Builder.CreateOr(Tmp6, Tmp5, "bswap.or2"); 249 Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or3"); 250 Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or4"); 251 Tmp8 = Builder.CreateOr(Tmp8, Tmp6, "bswap.or5"); 252 Tmp4 = Builder.CreateOr(Tmp4, Tmp2, "bswap.or6"); 253 V = Builder.CreateOr(Tmp8, Tmp4, "bswap.i64"); 254 break; 255 } 256 } 257 return V; 258 } 259 260 /// LowerCTPOP - Emit the code to lower ctpop of V before the specified 261 /// instruction IP. 262 static Value *LowerCTPOP(LLVMContext &Context, Value *V, Instruction *IP) { 263 assert(V->getType()->isIntegerTy() && "Can't ctpop a non-integer type!"); 264 265 static const uint64_t MaskValues[6] = { 266 0x5555555555555555ULL, 0x3333333333333333ULL, 267 0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL, 268 0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL 269 }; 270 271 IRBuilder<> Builder(IP->getParent(), IP); 272 273 unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); 274 unsigned WordSize = (BitSize + 63) / 64; 275 Value *Count = ConstantInt::get(V->getType(), 0); 276 277 for (unsigned n = 0; n < WordSize; ++n) { 278 Value *PartValue = V; 279 for (unsigned i = 1, ct = 0; i < (BitSize>64 ? 64 : BitSize); 280 i <<= 1, ++ct) { 281 Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]); 282 Value *LHS = Builder.CreateAnd(PartValue, MaskCst, "cppop.and1"); 283 Value *VShift = Builder.CreateLShr(PartValue, 284 ConstantInt::get(V->getType(), i), 285 "ctpop.sh"); 286 Value *RHS = Builder.CreateAnd(VShift, MaskCst, "cppop.and2"); 287 PartValue = Builder.CreateAdd(LHS, RHS, "ctpop.step"); 288 } 289 Count = Builder.CreateAdd(PartValue, Count, "ctpop.part"); 290 if (BitSize > 64) { 291 V = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 64), 292 "ctpop.part.sh"); 293 BitSize -= 64; 294 } 295 } 296 297 return Count; 298 } 299 300 /// LowerCTLZ - Emit the code to lower ctlz of V before the specified 301 /// instruction IP. 302 static Value *LowerCTLZ(LLVMContext &Context, Value *V, Instruction *IP) { 303 304 IRBuilder<> Builder(IP->getParent(), IP); 305 306 unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); 307 for (unsigned i = 1; i < BitSize; i <<= 1) { 308 Value *ShVal = ConstantInt::get(V->getType(), i); 309 ShVal = Builder.CreateLShr(V, ShVal, "ctlz.sh"); 310 V = Builder.CreateOr(V, ShVal, "ctlz.step"); 311 } 312 313 V = Builder.CreateNot(V); 314 return LowerCTPOP(Context, V, IP); 315 } 316 317 static void ReplaceFPIntrinsicWithCall(CallInst *CI, const char *Fname, 318 const char *Dname, 319 const char *LDname) { 320 CallSite CS(CI); 321 switch (CI->getArgOperand(0)->getType()->getTypeID()) { 322 default: llvm_unreachable("Invalid type in intrinsic"); 323 case Type::FloatTyID: 324 ReplaceCallWith(Fname, CI, CS.arg_begin(), CS.arg_end(), 325 Type::getFloatTy(CI->getContext())); 326 break; 327 case Type::DoubleTyID: 328 ReplaceCallWith(Dname, CI, CS.arg_begin(), CS.arg_end(), 329 Type::getDoubleTy(CI->getContext())); 330 break; 331 case Type::X86_FP80TyID: 332 case Type::FP128TyID: 333 case Type::PPC_FP128TyID: 334 ReplaceCallWith(LDname, CI, CS.arg_begin(), CS.arg_end(), 335 CI->getArgOperand(0)->getType()); 336 break; 337 } 338 } 339 340 void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) { 341 IRBuilder<> Builder(CI->getParent(), CI); 342 LLVMContext &Context = CI->getContext(); 343 344 const Function *Callee = CI->getCalledFunction(); 345 assert(Callee && "Cannot lower an indirect call!"); 346 347 CallSite CS(CI); 348 switch (Callee->getIntrinsicID()) { 349 case Intrinsic::not_intrinsic: 350 report_fatal_error("Cannot lower a call to a non-intrinsic function '"+ 351 Callee->getName() + "'!"); 352 default: 353 report_fatal_error("Code generator does not support intrinsic function '"+ 354 Callee->getName()+"'!"); 355 356 case Intrinsic::expect: { 357 // Just replace __builtin_expect(exp, c) with EXP. 358 Value *V = CI->getArgOperand(0); 359 CI->replaceAllUsesWith(V); 360 break; 361 } 362 363 // The setjmp/longjmp intrinsics should only exist in the code if it was 364 // never optimized (ie, right out of the CFE), or if it has been hacked on 365 // by the lowerinvoke pass. In both cases, the right thing to do is to 366 // convert the call to an explicit setjmp or longjmp call. 367 case Intrinsic::setjmp: { 368 Value *V = ReplaceCallWith("setjmp", CI, CS.arg_begin(), CS.arg_end(), 369 Type::getInt32Ty(Context)); 370 if (!CI->getType()->isVoidTy()) 371 CI->replaceAllUsesWith(V); 372 break; 373 } 374 case Intrinsic::sigsetjmp: 375 if (!CI->getType()->isVoidTy()) 376 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 377 break; 378 379 case Intrinsic::longjmp: { 380 ReplaceCallWith("longjmp", CI, CS.arg_begin(), CS.arg_end(), 381 Type::getVoidTy(Context)); 382 break; 383 } 384 385 case Intrinsic::siglongjmp: { 386 // Insert the call to abort 387 ReplaceCallWith("abort", CI, CS.arg_end(), CS.arg_end(), 388 Type::getVoidTy(Context)); 389 break; 390 } 391 case Intrinsic::ctpop: 392 CI->replaceAllUsesWith(LowerCTPOP(Context, CI->getArgOperand(0), CI)); 393 break; 394 395 case Intrinsic::bswap: 396 CI->replaceAllUsesWith(LowerBSWAP(Context, CI->getArgOperand(0), CI)); 397 break; 398 399 case Intrinsic::ctlz: 400 CI->replaceAllUsesWith(LowerCTLZ(Context, CI->getArgOperand(0), CI)); 401 break; 402 403 case Intrinsic::cttz: { 404 // cttz(x) -> ctpop(~X & (X-1)) 405 Value *Src = CI->getArgOperand(0); 406 Value *NotSrc = Builder.CreateNot(Src); 407 NotSrc->setName(Src->getName() + ".not"); 408 Value *SrcM1 = ConstantInt::get(Src->getType(), 1); 409 SrcM1 = Builder.CreateSub(Src, SrcM1); 410 Src = LowerCTPOP(Context, Builder.CreateAnd(NotSrc, SrcM1), CI); 411 CI->replaceAllUsesWith(Src); 412 break; 413 } 414 415 case Intrinsic::stacksave: 416 case Intrinsic::stackrestore: { 417 if (!Warned) 418 errs() << "WARNING: this target does not support the llvm.stack" 419 << (Callee->getIntrinsicID() == Intrinsic::stacksave ? 420 "save" : "restore") << " intrinsic.\n"; 421 Warned = true; 422 if (Callee->getIntrinsicID() == Intrinsic::stacksave) 423 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 424 break; 425 } 426 427 case Intrinsic::returnaddress: 428 case Intrinsic::frameaddress: 429 errs() << "WARNING: this target does not support the llvm." 430 << (Callee->getIntrinsicID() == Intrinsic::returnaddress ? 431 "return" : "frame") << "address intrinsic.\n"; 432 CI->replaceAllUsesWith(ConstantPointerNull::get( 433 cast<PointerType>(CI->getType()))); 434 break; 435 436 case Intrinsic::prefetch: 437 break; // Simply strip out prefetches on unsupported architectures 438 439 case Intrinsic::pcmarker: 440 break; // Simply strip out pcmarker on unsupported architectures 441 case Intrinsic::readcyclecounter: { 442 errs() << "WARNING: this target does not support the llvm.readcyclecoun" 443 << "ter intrinsic. It is being lowered to a constant 0\n"; 444 CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0)); 445 break; 446 } 447 448 case Intrinsic::dbg_declare: 449 break; // Simply strip out debugging intrinsics 450 451 case Intrinsic::eh_typeid_for: 452 // Return something different to eh_selector. 453 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1)); 454 break; 455 456 case Intrinsic::annotation: 457 case Intrinsic::ptr_annotation: 458 // Just drop the annotation, but forward the value 459 CI->replaceAllUsesWith(CI->getOperand(0)); 460 break; 461 462 case Intrinsic::var_annotation: 463 break; // Strip out annotate intrinsic 464 465 case Intrinsic::memcpy: { 466 Type *IntPtr = TD.getIntPtrType(Context); 467 Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr, 468 /* isSigned */ false); 469 Value *Ops[3]; 470 Ops[0] = CI->getArgOperand(0); 471 Ops[1] = CI->getArgOperand(1); 472 Ops[2] = Size; 473 ReplaceCallWith("memcpy", CI, Ops, Ops+3, CI->getArgOperand(0)->getType()); 474 break; 475 } 476 case Intrinsic::memmove: { 477 Type *IntPtr = TD.getIntPtrType(Context); 478 Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr, 479 /* isSigned */ false); 480 Value *Ops[3]; 481 Ops[0] = CI->getArgOperand(0); 482 Ops[1] = CI->getArgOperand(1); 483 Ops[2] = Size; 484 ReplaceCallWith("memmove", CI, Ops, Ops+3, CI->getArgOperand(0)->getType()); 485 break; 486 } 487 case Intrinsic::memset: { 488 Type *IntPtr = TD.getIntPtrType(Context); 489 Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr, 490 /* isSigned */ false); 491 Value *Ops[3]; 492 Ops[0] = CI->getArgOperand(0); 493 // Extend the amount to i32. 494 Ops[1] = Builder.CreateIntCast(CI->getArgOperand(1), 495 Type::getInt32Ty(Context), 496 /* isSigned */ false); 497 Ops[2] = Size; 498 ReplaceCallWith("memset", CI, Ops, Ops+3, CI->getArgOperand(0)->getType()); 499 break; 500 } 501 case Intrinsic::sqrt: { 502 ReplaceFPIntrinsicWithCall(CI, "sqrtf", "sqrt", "sqrtl"); 503 break; 504 } 505 case Intrinsic::log: { 506 ReplaceFPIntrinsicWithCall(CI, "logf", "log", "logl"); 507 break; 508 } 509 case Intrinsic::log2: { 510 ReplaceFPIntrinsicWithCall(CI, "log2f", "log2", "log2l"); 511 break; 512 } 513 case Intrinsic::log10: { 514 ReplaceFPIntrinsicWithCall(CI, "log10f", "log10", "log10l"); 515 break; 516 } 517 case Intrinsic::exp: { 518 ReplaceFPIntrinsicWithCall(CI, "expf", "exp", "expl"); 519 break; 520 } 521 case Intrinsic::exp2: { 522 ReplaceFPIntrinsicWithCall(CI, "exp2f", "exp2", "exp2l"); 523 break; 524 } 525 case Intrinsic::pow: { 526 ReplaceFPIntrinsicWithCall(CI, "powf", "pow", "powl"); 527 break; 528 } 529 case Intrinsic::flt_rounds: 530 // Lower to "round to the nearest" 531 if (!CI->getType()->isVoidTy()) 532 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1)); 533 break; 534 case Intrinsic::invariant_start: 535 case Intrinsic::lifetime_start: 536 // Discard region information. 537 CI->replaceAllUsesWith(UndefValue::get(CI->getType())); 538 break; 539 case Intrinsic::invariant_end: 540 case Intrinsic::lifetime_end: 541 // Discard region information. 542 break; 543 } 544 545 assert(CI->use_empty() && 546 "Lowering should have eliminated any uses of the intrinsic call!"); 547 CI->eraseFromParent(); 548 } 549 550 bool IntrinsicLowering::LowerToByteSwap(CallInst *CI) { 551 // Verify this is a simple bswap. 552 if (CI->getNumArgOperands() != 1 || 553 CI->getType() != CI->getArgOperand(0)->getType() || 554 !CI->getType()->isIntegerTy()) 555 return false; 556 557 IntegerType *Ty = dyn_cast<IntegerType>(CI->getType()); 558 if (!Ty) 559 return false; 560 561 // Okay, we can do this xform, do so now. 562 Module *M = CI->getParent()->getParent()->getParent(); 563 Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Ty); 564 565 Value *Op = CI->getArgOperand(0); 566 Op = CallInst::Create(Int, Op, CI->getName(), CI); 567 568 CI->replaceAllUsesWith(Op); 569 CI->eraseFromParent(); 570 return true; 571 } 572
