IntrinsicLowering.cpp revision c25e7581b9b8088910da31702d4ca21c4734c6d7
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/Constants.h" 15#include "llvm/DerivedTypes.h" 16#include "llvm/Module.h" 17#include "llvm/Type.h" 18#include "llvm/CodeGen/IntrinsicLowering.h" 19#include "llvm/Support/IRBuilder.h" 20#include "llvm/Support/ErrorHandling.h" 21#include "llvm/Target/TargetData.h" 22#include "llvm/ADT/SmallVector.h" 23using namespace llvm; 24 25template <class ArgIt> 26static void EnsureFunctionExists(Module &M, const char *Name, 27 ArgIt ArgBegin, ArgIt ArgEnd, 28 const Type *RetTy) { 29 // Insert a correctly-typed definition now. 30 std::vector<const Type *> ParamTys; 31 for (ArgIt I = ArgBegin; I != ArgEnd; ++I) 32 ParamTys.push_back(I->getType()); 33 M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false)); 34} 35 36static void EnsureFPIntrinsicsExist(Module &M, Function *Fn, 37 const char *FName, 38 const char *DName, const char *LDName) { 39 // Insert definitions for all the floating point types. 40 switch((int)Fn->arg_begin()->getType()->getTypeID()) { 41 case Type::FloatTyID: 42 EnsureFunctionExists(M, FName, Fn->arg_begin(), Fn->arg_end(), 43 Type::FloatTy); 44 break; 45 case Type::DoubleTyID: 46 EnsureFunctionExists(M, DName, Fn->arg_begin(), Fn->arg_end(), 47 Type::DoubleTy); 48 break; 49 case Type::X86_FP80TyID: 50 case Type::FP128TyID: 51 case Type::PPC_FP128TyID: 52 EnsureFunctionExists(M, LDName, Fn->arg_begin(), Fn->arg_end(), 53 Fn->arg_begin()->getType()); 54 break; 55 } 56} 57 58/// ReplaceCallWith - This function is used when we want to lower an intrinsic 59/// call to a call of an external function. This handles hard cases such as 60/// when there was already a prototype for the external function, and if that 61/// prototype doesn't match the arguments we expect to pass in. 62template <class ArgIt> 63static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI, 64 ArgIt ArgBegin, ArgIt ArgEnd, 65 const Type *RetTy) { 66 // If we haven't already looked up this function, check to see if the 67 // program already contains a function with this name. 68 Module *M = CI->getParent()->getParent()->getParent(); 69 // Get or insert the definition now. 70 std::vector<const Type *> ParamTys; 71 for (ArgIt I = ArgBegin; I != ArgEnd; ++I) 72 ParamTys.push_back((*I)->getType()); 73 Constant* FCache = M->getOrInsertFunction(NewFn, 74 FunctionType::get(RetTy, ParamTys, false)); 75 76 IRBuilder<> Builder(CI->getParent(), CI); 77 SmallVector<Value *, 8> Args(ArgBegin, ArgEnd); 78 CallInst *NewCI = Builder.CreateCall(FCache, Args.begin(), Args.end()); 79 NewCI->setName(CI->getName()); 80 if (!CI->use_empty()) 81 CI->replaceAllUsesWith(NewCI); 82 return NewCI; 83} 84 85void IntrinsicLowering::AddPrototypes(Module &M) { 86 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 87 if (I->isDeclaration() && !I->use_empty()) 88 switch (I->getIntrinsicID()) { 89 default: break; 90 case Intrinsic::setjmp: 91 EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(), 92 Type::Int32Ty); 93 break; 94 case Intrinsic::longjmp: 95 EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(), 96 Type::VoidTy); 97 break; 98 case Intrinsic::siglongjmp: 99 EnsureFunctionExists(M, "abort", I->arg_end(), I->arg_end(), 100 Type::VoidTy); 101 break; 102 case Intrinsic::memcpy: 103 M.getOrInsertFunction("memcpy", PointerType::getUnqual(Type::Int8Ty), 104 PointerType::getUnqual(Type::Int8Ty), 105 PointerType::getUnqual(Type::Int8Ty), 106 TD.getIntPtrType(), (Type *)0); 107 break; 108 case Intrinsic::memmove: 109 M.getOrInsertFunction("memmove", PointerType::getUnqual(Type::Int8Ty), 110 PointerType::getUnqual(Type::Int8Ty), 111 PointerType::getUnqual(Type::Int8Ty), 112 TD.getIntPtrType(), (Type *)0); 113 break; 114 case Intrinsic::memset: 115 M.getOrInsertFunction("memset", PointerType::getUnqual(Type::Int8Ty), 116 PointerType::getUnqual(Type::Int8Ty), 117 Type::Int32Ty, 118 TD.getIntPtrType(), (Type *)0); 119 break; 120 case Intrinsic::sqrt: 121 EnsureFPIntrinsicsExist(M, I, "sqrtf", "sqrt", "sqrtl"); 122 break; 123 case Intrinsic::sin: 124 EnsureFPIntrinsicsExist(M, I, "sinf", "sin", "sinl"); 125 break; 126 case Intrinsic::cos: 127 EnsureFPIntrinsicsExist(M, I, "cosf", "cos", "cosl"); 128 break; 129 case Intrinsic::pow: 130 EnsureFPIntrinsicsExist(M, I, "powf", "pow", "powl"); 131 break; 132 case Intrinsic::log: 133 EnsureFPIntrinsicsExist(M, I, "logf", "log", "logl"); 134 break; 135 case Intrinsic::log2: 136 EnsureFPIntrinsicsExist(M, I, "log2f", "log2", "log2l"); 137 break; 138 case Intrinsic::log10: 139 EnsureFPIntrinsicsExist(M, I, "log10f", "log10", "log10l"); 140 break; 141 case Intrinsic::exp: 142 EnsureFPIntrinsicsExist(M, I, "expf", "exp", "expl"); 143 break; 144 case Intrinsic::exp2: 145 EnsureFPIntrinsicsExist(M, I, "exp2f", "exp2", "exp2l"); 146 break; 147 } 148} 149 150/// LowerBSWAP - Emit the code to lower bswap of V before the specified 151/// instruction IP. 152static Value *LowerBSWAP(Value *V, Instruction *IP) { 153 assert(V->getType()->isInteger() && "Can't bswap a non-integer type!"); 154 155 unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); 156 157 IRBuilder<> Builder(IP->getParent(), IP); 158 159 switch(BitSize) { 160 default: LLVM_UNREACHABLE("Unhandled type size of value to byteswap!"); 161 case 16: { 162 Value *Tmp1 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8), 163 "bswap.2"); 164 Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8), 165 "bswap.1"); 166 V = Builder.CreateOr(Tmp1, Tmp2, "bswap.i16"); 167 break; 168 } 169 case 32: { 170 Value *Tmp4 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24), 171 "bswap.4"); 172 Value *Tmp3 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8), 173 "bswap.3"); 174 Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8), 175 "bswap.2"); 176 Value *Tmp1 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 24), 177 "bswap.1"); 178 Tmp3 = Builder.CreateAnd(Tmp3, ConstantInt::get(Type::Int32Ty, 0xFF0000), 179 "bswap.and3"); 180 Tmp2 = Builder.CreateAnd(Tmp2, ConstantInt::get(Type::Int32Ty, 0xFF00), 181 "bswap.and2"); 182 Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or1"); 183 Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or2"); 184 V = Builder.CreateOr(Tmp4, Tmp2, "bswap.i32"); 185 break; 186 } 187 case 64: { 188 Value *Tmp8 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 56), 189 "bswap.8"); 190 Value *Tmp7 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 40), 191 "bswap.7"); 192 Value *Tmp6 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24), 193 "bswap.6"); 194 Value *Tmp5 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8), 195 "bswap.5"); 196 Value* Tmp4 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8), 197 "bswap.4"); 198 Value* Tmp3 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 24), 199 "bswap.3"); 200 Value* Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 40), 201 "bswap.2"); 202 Value* Tmp1 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 56), 203 "bswap.1"); 204 Tmp7 = Builder.CreateAnd(Tmp7, 205 ConstantInt::get(Type::Int64Ty, 206 0xFF000000000000ULL), 207 "bswap.and7"); 208 Tmp6 = Builder.CreateAnd(Tmp6, 209 ConstantInt::get(Type::Int64Ty, 210 0xFF0000000000ULL), 211 "bswap.and6"); 212 Tmp5 = Builder.CreateAnd(Tmp5, 213 ConstantInt::get(Type::Int64Ty, 0xFF00000000ULL), 214 "bswap.and5"); 215 Tmp4 = Builder.CreateAnd(Tmp4, 216 ConstantInt::get(Type::Int64Ty, 0xFF000000ULL), 217 "bswap.and4"); 218 Tmp3 = Builder.CreateAnd(Tmp3, 219 ConstantInt::get(Type::Int64Ty, 0xFF0000ULL), 220 "bswap.and3"); 221 Tmp2 = Builder.CreateAnd(Tmp2, 222 ConstantInt::get(Type::Int64Ty, 0xFF00ULL), 223 "bswap.and2"); 224 Tmp8 = Builder.CreateOr(Tmp8, Tmp7, "bswap.or1"); 225 Tmp6 = Builder.CreateOr(Tmp6, Tmp5, "bswap.or2"); 226 Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or3"); 227 Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or4"); 228 Tmp8 = Builder.CreateOr(Tmp8, Tmp6, "bswap.or5"); 229 Tmp4 = Builder.CreateOr(Tmp4, Tmp2, "bswap.or6"); 230 V = Builder.CreateOr(Tmp8, Tmp4, "bswap.i64"); 231 break; 232 } 233 } 234 return V; 235} 236 237/// LowerCTPOP - Emit the code to lower ctpop of V before the specified 238/// instruction IP. 239static Value *LowerCTPOP(Value *V, Instruction *IP) { 240 assert(V->getType()->isInteger() && "Can't ctpop a non-integer type!"); 241 242 static const uint64_t MaskValues[6] = { 243 0x5555555555555555ULL, 0x3333333333333333ULL, 244 0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL, 245 0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL 246 }; 247 248 IRBuilder<> Builder(IP->getParent(), IP); 249 250 unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); 251 unsigned WordSize = (BitSize + 63) / 64; 252 Value *Count = ConstantInt::get(V->getType(), 0); 253 254 for (unsigned n = 0; n < WordSize; ++n) { 255 Value *PartValue = V; 256 for (unsigned i = 1, ct = 0; i < (BitSize>64 ? 64 : BitSize); 257 i <<= 1, ++ct) { 258 Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]); 259 Value *LHS = Builder.CreateAnd(PartValue, MaskCst, "cppop.and1"); 260 Value *VShift = Builder.CreateLShr(PartValue, 261 ConstantInt::get(V->getType(), i), 262 "ctpop.sh"); 263 Value *RHS = Builder.CreateAnd(VShift, MaskCst, "cppop.and2"); 264 PartValue = Builder.CreateAdd(LHS, RHS, "ctpop.step"); 265 } 266 Count = Builder.CreateAdd(PartValue, Count, "ctpop.part"); 267 if (BitSize > 64) { 268 V = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 64), 269 "ctpop.part.sh"); 270 BitSize -= 64; 271 } 272 } 273 274 return Count; 275} 276 277/// LowerCTLZ - Emit the code to lower ctlz of V before the specified 278/// instruction IP. 279static Value *LowerCTLZ(Value *V, Instruction *IP) { 280 281 IRBuilder<> Builder(IP->getParent(), IP); 282 283 unsigned BitSize = V->getType()->getPrimitiveSizeInBits(); 284 for (unsigned i = 1; i < BitSize; i <<= 1) { 285 Value *ShVal = ConstantInt::get(V->getType(), i); 286 ShVal = Builder.CreateLShr(V, ShVal, "ctlz.sh"); 287 V = Builder.CreateOr(V, ShVal, "ctlz.step"); 288 } 289 290 V = Builder.CreateNot(V); 291 return LowerCTPOP(V, IP); 292} 293 294/// Convert the llvm.part.select.iX.iY intrinsic. This intrinsic takes 295/// three integer arguments. The first argument is the Value from which the 296/// bits will be selected. It may be of any bit width. The second and third 297/// arguments specify a range of bits to select with the second argument 298/// specifying the low bit and the third argument specifying the high bit. Both 299/// must be type i32. The result is the corresponding selected bits from the 300/// Value in the same width as the Value (first argument). If the low bit index 301/// is higher than the high bit index then the inverse selection is done and 302/// the bits are returned in inverse order. 303/// @brief Lowering of llvm.part.select intrinsic. 304static Instruction *LowerPartSelect(CallInst *CI) { 305 IRBuilder<> Builder(*CI->getParent()->getContext()); 306 307 // Make sure we're dealing with a part select intrinsic here 308 Function *F = CI->getCalledFunction(); 309 const FunctionType *FT = F->getFunctionType(); 310 if (!F->isDeclaration() || !FT->getReturnType()->isInteger() || 311 FT->getNumParams() != 3 || !FT->getParamType(0)->isInteger() || 312 !FT->getParamType(1)->isInteger() || !FT->getParamType(2)->isInteger()) 313 return CI; 314 315 // Get the intrinsic implementation function by converting all the . to _ 316 // in the intrinsic's function name and then reconstructing the function 317 // declaration. 318 std::string Name(F->getName()); 319 for (unsigned i = 4; i < Name.length(); ++i) 320 if (Name[i] == '.') 321 Name[i] = '_'; 322 Module* M = F->getParent(); 323 F = cast<Function>(M->getOrInsertFunction(Name, FT)); 324 F->setLinkage(GlobalValue::WeakAnyLinkage); 325 326 // If we haven't defined the impl function yet, do so now 327 if (F->isDeclaration()) { 328 329 // Get the arguments to the function 330 Function::arg_iterator args = F->arg_begin(); 331 Value* Val = args++; Val->setName("Val"); 332 Value* Lo = args++; Lo->setName("Lo"); 333 Value* Hi = args++; Hi->setName("High"); 334 335 // We want to select a range of bits here such that [Hi, Lo] is shifted 336 // down to the low bits. However, it is quite possible that Hi is smaller 337 // than Lo in which case the bits have to be reversed. 338 339 // Create the blocks we will need for the two cases (forward, reverse) 340 BasicBlock* CurBB = BasicBlock::Create("entry", F); 341 BasicBlock *RevSize = BasicBlock::Create("revsize", CurBB->getParent()); 342 BasicBlock *FwdSize = BasicBlock::Create("fwdsize", CurBB->getParent()); 343 BasicBlock *Compute = BasicBlock::Create("compute", CurBB->getParent()); 344 BasicBlock *Reverse = BasicBlock::Create("reverse", CurBB->getParent()); 345 BasicBlock *RsltBlk = BasicBlock::Create("result", CurBB->getParent()); 346 347 Builder.SetInsertPoint(CurBB); 348 349 // Cast Hi and Lo to the size of Val so the widths are all the same 350 if (Hi->getType() != Val->getType()) 351 Hi = Builder.CreateIntCast(Hi, Val->getType(), /* isSigned */ false, 352 "tmp"); 353 if (Lo->getType() != Val->getType()) 354 Lo = Builder.CreateIntCast(Lo, Val->getType(), /* isSigned */ false, 355 "tmp"); 356 357 // Compute a few things that both cases will need, up front. 358 Constant* Zero = ConstantInt::get(Val->getType(), 0); 359 Constant* One = ConstantInt::get(Val->getType(), 1); 360 Constant* AllOnes = ConstantInt::getAllOnesValue(Val->getType()); 361 362 // Compare the Hi and Lo bit positions. This is used to determine 363 // which case we have (forward or reverse) 364 Value *Cmp = Builder.CreateICmpULT(Hi, Lo, "less"); 365 Builder.CreateCondBr(Cmp, RevSize, FwdSize); 366 367 // First, compute the number of bits in the forward case. 368 Builder.SetInsertPoint(FwdSize); 369 Value* FBitSize = Builder.CreateSub(Hi, Lo, "fbits"); 370 Builder.CreateBr(Compute); 371 372 // Second, compute the number of bits in the reverse case. 373 Builder.SetInsertPoint(RevSize); 374 Value* RBitSize = Builder.CreateSub(Lo, Hi, "rbits"); 375 Builder.CreateBr(Compute); 376 377 // Now, compute the bit range. Start by getting the bitsize and the shift 378 // amount (either Hi or Lo) from PHI nodes. Then we compute a mask for 379 // the number of bits we want in the range. We shift the bits down to the 380 // least significant bits, apply the mask to zero out unwanted high bits, 381 // and we have computed the "forward" result. It may still need to be 382 // reversed. 383 Builder.SetInsertPoint(Compute); 384 385 // Get the BitSize from one of the two subtractions 386 PHINode *BitSize = Builder.CreatePHI(Val->getType(), "bits"); 387 BitSize->reserveOperandSpace(2); 388 BitSize->addIncoming(FBitSize, FwdSize); 389 BitSize->addIncoming(RBitSize, RevSize); 390 391 // Get the ShiftAmount as the smaller of Hi/Lo 392 PHINode *ShiftAmt = Builder.CreatePHI(Val->getType(), "shiftamt"); 393 ShiftAmt->reserveOperandSpace(2); 394 ShiftAmt->addIncoming(Lo, FwdSize); 395 ShiftAmt->addIncoming(Hi, RevSize); 396 397 // Increment the bit size 398 Value *BitSizePlusOne = Builder.CreateAdd(BitSize, One, "bits"); 399 400 // Create a Mask to zero out the high order bits. 401 Value* Mask = Builder.CreateShl(AllOnes, BitSizePlusOne, "mask"); 402 Mask = Builder.CreateNot(Mask, "mask"); 403 404 // Shift the bits down and apply the mask 405 Value* FRes = Builder.CreateLShr(Val, ShiftAmt, "fres"); 406 FRes = Builder.CreateAnd(FRes, Mask, "fres"); 407 Builder.CreateCondBr(Cmp, Reverse, RsltBlk); 408 409 // In the Reverse block we have the mask already in FRes but we must reverse 410 // it by shifting FRes bits right and putting them in RRes by shifting them 411 // in from left. 412 Builder.SetInsertPoint(Reverse); 413 414 // First set up our loop counters 415 PHINode *Count = Builder.CreatePHI(Val->getType(), "count"); 416 Count->reserveOperandSpace(2); 417 Count->addIncoming(BitSizePlusOne, Compute); 418 419 // Next, get the value that we are shifting. 420 PHINode *BitsToShift = Builder.CreatePHI(Val->getType(), "val"); 421 BitsToShift->reserveOperandSpace(2); 422 BitsToShift->addIncoming(FRes, Compute); 423 424 // Finally, get the result of the last computation 425 PHINode *RRes = Builder.CreatePHI(Val->getType(), "rres"); 426 RRes->reserveOperandSpace(2); 427 RRes->addIncoming(Zero, Compute); 428 429 // Decrement the counter 430 Value *Decr = Builder.CreateSub(Count, One, "decr"); 431 Count->addIncoming(Decr, Reverse); 432 433 // Compute the Bit that we want to move 434 Value *Bit = Builder.CreateAnd(BitsToShift, One, "bit"); 435 436 // Compute the new value for next iteration. 437 Value *NewVal = Builder.CreateLShr(BitsToShift, One, "rshift"); 438 BitsToShift->addIncoming(NewVal, Reverse); 439 440 // Shift the bit into the low bits of the result. 441 Value *NewRes = Builder.CreateShl(RRes, One, "lshift"); 442 NewRes = Builder.CreateOr(NewRes, Bit, "addbit"); 443 RRes->addIncoming(NewRes, Reverse); 444 445 // Terminate loop if we've moved all the bits. 446 Value *Cond = Builder.CreateICmpEQ(Decr, Zero, "cond"); 447 Builder.CreateCondBr(Cond, RsltBlk, Reverse); 448 449 // Finally, in the result block, select one of the two results with a PHI 450 // node and return the result; 451 Builder.SetInsertPoint(RsltBlk); 452 PHINode *BitSelect = Builder.CreatePHI(Val->getType(), "part_select"); 453 BitSelect->reserveOperandSpace(2); 454 BitSelect->addIncoming(FRes, Compute); 455 BitSelect->addIncoming(NewRes, Reverse); 456 Builder.CreateRet(BitSelect); 457 } 458 459 // Return a call to the implementation function 460 Builder.SetInsertPoint(CI->getParent(), CI); 461 CallInst *NewCI = Builder.CreateCall3(F, CI->getOperand(1), 462 CI->getOperand(2), CI->getOperand(3)); 463 NewCI->setName(CI->getName()); 464 return NewCI; 465} 466 467/// Convert the llvm.part.set.iX.iY.iZ intrinsic. This intrinsic takes 468/// four integer arguments (iAny %Value, iAny %Replacement, i32 %Low, i32 %High) 469/// The first two arguments can be any bit width. The result is the same width 470/// as %Value. The operation replaces bits between %Low and %High with the value 471/// in %Replacement. If %Replacement is not the same width, it is truncated or 472/// zero extended as appropriate to fit the bits being replaced. If %Low is 473/// greater than %High then the inverse set of bits are replaced. 474/// @brief Lowering of llvm.bit.part.set intrinsic. 475static Instruction *LowerPartSet(CallInst *CI) { 476 IRBuilder<> Builder(*CI->getParent()->getContext()); 477 478 // Make sure we're dealing with a part select intrinsic here 479 Function *F = CI->getCalledFunction(); 480 const FunctionType *FT = F->getFunctionType(); 481 if (!F->isDeclaration() || !FT->getReturnType()->isInteger() || 482 FT->getNumParams() != 4 || !FT->getParamType(0)->isInteger() || 483 !FT->getParamType(1)->isInteger() || !FT->getParamType(2)->isInteger() || 484 !FT->getParamType(3)->isInteger()) 485 return CI; 486 487 // Get the intrinsic implementation function by converting all the . to _ 488 // in the intrinsic's function name and then reconstructing the function 489 // declaration. 490 std::string Name(F->getName()); 491 for (unsigned i = 4; i < Name.length(); ++i) 492 if (Name[i] == '.') 493 Name[i] = '_'; 494 Module* M = F->getParent(); 495 F = cast<Function>(M->getOrInsertFunction(Name, FT)); 496 F->setLinkage(GlobalValue::WeakAnyLinkage); 497 498 // If we haven't defined the impl function yet, do so now 499 if (F->isDeclaration()) { 500 // Get the arguments for the function. 501 Function::arg_iterator args = F->arg_begin(); 502 Value* Val = args++; Val->setName("Val"); 503 Value* Rep = args++; Rep->setName("Rep"); 504 Value* Lo = args++; Lo->setName("Lo"); 505 Value* Hi = args++; Hi->setName("Hi"); 506 507 // Get some types we need 508 const IntegerType* ValTy = cast<IntegerType>(Val->getType()); 509 const IntegerType* RepTy = cast<IntegerType>(Rep->getType()); 510 uint32_t RepBits = RepTy->getBitWidth(); 511 512 // Constant Definitions 513 ConstantInt* RepBitWidth = ConstantInt::get(Type::Int32Ty, RepBits); 514 ConstantInt* RepMask = ConstantInt::getAllOnesValue(RepTy); 515 ConstantInt* ValMask = ConstantInt::getAllOnesValue(ValTy); 516 ConstantInt* One = ConstantInt::get(Type::Int32Ty, 1); 517 ConstantInt* ValOne = ConstantInt::get(ValTy, 1); 518 ConstantInt* Zero = ConstantInt::get(Type::Int32Ty, 0); 519 ConstantInt* ValZero = ConstantInt::get(ValTy, 0); 520 521 // Basic blocks we fill in below. 522 BasicBlock* entry = BasicBlock::Create("entry", F, 0); 523 BasicBlock* large = BasicBlock::Create("large", F, 0); 524 BasicBlock* small = BasicBlock::Create("small", F, 0); 525 BasicBlock* reverse = BasicBlock::Create("reverse", F, 0); 526 BasicBlock* result = BasicBlock::Create("result", F, 0); 527 528 // BASIC BLOCK: entry 529 Builder.SetInsertPoint(entry); 530 // First, get the number of bits that we're placing as an i32 531 Value* is_forward = Builder.CreateICmpULT(Lo, Hi); 532 Value* Hi_pn = Builder.CreateSelect(is_forward, Hi, Lo); 533 Value* Lo_pn = Builder.CreateSelect(is_forward, Lo, Hi); 534 Value* NumBits = Builder.CreateSub(Hi_pn, Lo_pn); 535 NumBits = Builder.CreateAdd(NumBits, One); 536 // Now, convert Lo and Hi to ValTy bit width 537 Lo = Builder.CreateIntCast(Lo_pn, ValTy, /* isSigned */ false); 538 // Determine if the replacement bits are larger than the number of bits we 539 // are replacing and deal with it. 540 Value* is_large = Builder.CreateICmpULT(NumBits, RepBitWidth); 541 Builder.CreateCondBr(is_large, large, small); 542 543 // BASIC BLOCK: large 544 Builder.SetInsertPoint(large); 545 Value* MaskBits = Builder.CreateSub(RepBitWidth, NumBits); 546 MaskBits = Builder.CreateIntCast(MaskBits, RepMask->getType(), 547 /* isSigned */ false); 548 Value* Mask1 = Builder.CreateLShr(RepMask, MaskBits); 549 Value* Rep2 = Builder.CreateAnd(Mask1, Rep); 550 Builder.CreateBr(small); 551 552 // BASIC BLOCK: small 553 Builder.SetInsertPoint(small); 554 PHINode* Rep3 = Builder.CreatePHI(RepTy); 555 Rep3->reserveOperandSpace(2); 556 Rep3->addIncoming(Rep2, large); 557 Rep3->addIncoming(Rep, entry); 558 Value* Rep4 = Builder.CreateIntCast(Rep3, ValTy, /* isSigned */ false); 559 Builder.CreateCondBr(is_forward, result, reverse); 560 561 // BASIC BLOCK: reverse (reverses the bits of the replacement) 562 Builder.SetInsertPoint(reverse); 563 // Set up our loop counter as a PHI so we can decrement on each iteration. 564 // We will loop for the number of bits in the replacement value. 565 PHINode *Count = Builder.CreatePHI(Type::Int32Ty, "count"); 566 Count->reserveOperandSpace(2); 567 Count->addIncoming(NumBits, small); 568 569 // Get the value that we are shifting bits out of as a PHI because 570 // we'll change this with each iteration. 571 PHINode *BitsToShift = Builder.CreatePHI(Val->getType(), "val"); 572 BitsToShift->reserveOperandSpace(2); 573 BitsToShift->addIncoming(Rep4, small); 574 575 // Get the result of the last computation or zero on first iteration 576 PHINode *RRes = Builder.CreatePHI(Val->getType(), "rres"); 577 RRes->reserveOperandSpace(2); 578 RRes->addIncoming(ValZero, small); 579 580 // Decrement the loop counter by one 581 Value *Decr = Builder.CreateSub(Count, One); 582 Count->addIncoming(Decr, reverse); 583 584 // Get the bit that we want to move into the result 585 Value *Bit = Builder.CreateAnd(BitsToShift, ValOne); 586 587 // Compute the new value of the bits to shift for the next iteration. 588 Value *NewVal = Builder.CreateLShr(BitsToShift, ValOne); 589 BitsToShift->addIncoming(NewVal, reverse); 590 591 // Shift the bit we extracted into the low bit of the result. 592 Value *NewRes = Builder.CreateShl(RRes, ValOne); 593 NewRes = Builder.CreateOr(NewRes, Bit); 594 RRes->addIncoming(NewRes, reverse); 595 596 // Terminate loop if we've moved all the bits. 597 Value *Cond = Builder.CreateICmpEQ(Decr, Zero); 598 Builder.CreateCondBr(Cond, result, reverse); 599 600 // BASIC BLOCK: result 601 Builder.SetInsertPoint(result); 602 PHINode *Rplcmnt = Builder.CreatePHI(Val->getType()); 603 Rplcmnt->reserveOperandSpace(2); 604 Rplcmnt->addIncoming(NewRes, reverse); 605 Rplcmnt->addIncoming(Rep4, small); 606 Value* t0 = Builder.CreateIntCast(NumBits, ValTy, /* isSigned */ false); 607 Value* t1 = Builder.CreateShl(ValMask, Lo); 608 Value* t2 = Builder.CreateNot(t1); 609 Value* t3 = Builder.CreateShl(t1, t0); 610 Value* t4 = Builder.CreateOr(t2, t3); 611 Value* t5 = Builder.CreateAnd(t4, Val); 612 Value* t6 = Builder.CreateShl(Rplcmnt, Lo); 613 Value* Rslt = Builder.CreateOr(t5, t6, "part_set"); 614 Builder.CreateRet(Rslt); 615 } 616 617 // Return a call to the implementation function 618 Builder.SetInsertPoint(CI->getParent(), CI); 619 CallInst *NewCI = Builder.CreateCall4(F, CI->getOperand(1), 620 CI->getOperand(2), CI->getOperand(3), 621 CI->getOperand(4)); 622 NewCI->setName(CI->getName()); 623 return NewCI; 624} 625 626static void ReplaceFPIntrinsicWithCall(CallInst *CI, const char *Fname, 627 const char *Dname, 628 const char *LDname) { 629 switch (CI->getOperand(1)->getType()->getTypeID()) { 630 default: LLVM_UNREACHABLE( "Invalid type in intrinsic"); 631 case Type::FloatTyID: 632 ReplaceCallWith(Fname, CI, CI->op_begin() + 1, CI->op_end(), 633 Type::FloatTy); 634 break; 635 case Type::DoubleTyID: 636 ReplaceCallWith(Dname, CI, CI->op_begin() + 1, CI->op_end(), 637 Type::DoubleTy); 638 break; 639 case Type::X86_FP80TyID: 640 case Type::FP128TyID: 641 case Type::PPC_FP128TyID: 642 ReplaceCallWith(LDname, CI, CI->op_begin() + 1, CI->op_end(), 643 CI->getOperand(1)->getType()); 644 break; 645 } 646} 647 648void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) { 649 IRBuilder<> Builder(CI->getParent(), CI); 650 651 Function *Callee = CI->getCalledFunction(); 652 assert(Callee && "Cannot lower an indirect call!"); 653 654 switch (Callee->getIntrinsicID()) { 655 case Intrinsic::not_intrinsic: 656 llvm_report_error("Cannot lower a call to a non-intrinsic function '"+ 657 Callee->getName() + "'!"); 658 default: 659 llvm_report_error("Code generator does not support intrinsic function '"+ 660 Callee->getName()+"'!"); 661 662 // The setjmp/longjmp intrinsics should only exist in the code if it was 663 // never optimized (ie, right out of the CFE), or if it has been hacked on 664 // by the lowerinvoke pass. In both cases, the right thing to do is to 665 // convert the call to an explicit setjmp or longjmp call. 666 case Intrinsic::setjmp: { 667 Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin() + 1, CI->op_end(), 668 Type::Int32Ty); 669 if (CI->getType() != Type::VoidTy) 670 CI->replaceAllUsesWith(V); 671 break; 672 } 673 case Intrinsic::sigsetjmp: 674 if (CI->getType() != Type::VoidTy) 675 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 676 break; 677 678 case Intrinsic::longjmp: { 679 ReplaceCallWith("longjmp", CI, CI->op_begin() + 1, CI->op_end(), 680 Type::VoidTy); 681 break; 682 } 683 684 case Intrinsic::siglongjmp: { 685 // Insert the call to abort 686 ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(), 687 Type::VoidTy); 688 break; 689 } 690 case Intrinsic::ctpop: 691 CI->replaceAllUsesWith(LowerCTPOP(CI->getOperand(1), CI)); 692 break; 693 694 case Intrinsic::bswap: 695 CI->replaceAllUsesWith(LowerBSWAP(CI->getOperand(1), CI)); 696 break; 697 698 case Intrinsic::ctlz: 699 CI->replaceAllUsesWith(LowerCTLZ(CI->getOperand(1), CI)); 700 break; 701 702 case Intrinsic::cttz: { 703 // cttz(x) -> ctpop(~X & (X-1)) 704 Value *Src = CI->getOperand(1); 705 Value *NotSrc = Builder.CreateNot(Src); 706 NotSrc->setName(Src->getName() + ".not"); 707 Value *SrcM1 = ConstantInt::get(Src->getType(), 1); 708 SrcM1 = Builder.CreateSub(Src, SrcM1); 709 Src = LowerCTPOP(Builder.CreateAnd(NotSrc, SrcM1), CI); 710 CI->replaceAllUsesWith(Src); 711 break; 712 } 713 714 case Intrinsic::part_select: 715 CI->replaceAllUsesWith(LowerPartSelect(CI)); 716 break; 717 718 case Intrinsic::part_set: 719 CI->replaceAllUsesWith(LowerPartSet(CI)); 720 break; 721 722 case Intrinsic::stacksave: 723 case Intrinsic::stackrestore: { 724 if (!Warned) 725 cerr << "WARNING: this target does not support the llvm.stack" 726 << (Callee->getIntrinsicID() == Intrinsic::stacksave ? 727 "save" : "restore") << " intrinsic.\n"; 728 Warned = true; 729 if (Callee->getIntrinsicID() == Intrinsic::stacksave) 730 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 731 break; 732 } 733 734 case Intrinsic::returnaddress: 735 case Intrinsic::frameaddress: 736 cerr << "WARNING: this target does not support the llvm." 737 << (Callee->getIntrinsicID() == Intrinsic::returnaddress ? 738 "return" : "frame") << "address intrinsic.\n"; 739 CI->replaceAllUsesWith(ConstantPointerNull::get( 740 cast<PointerType>(CI->getType()))); 741 break; 742 743 case Intrinsic::prefetch: 744 break; // Simply strip out prefetches on unsupported architectures 745 746 case Intrinsic::pcmarker: 747 break; // Simply strip out pcmarker on unsupported architectures 748 case Intrinsic::readcyclecounter: { 749 cerr << "WARNING: this target does not support the llvm.readcyclecoun" 750 << "ter intrinsic. It is being lowered to a constant 0\n"; 751 CI->replaceAllUsesWith(ConstantInt::get(Type::Int64Ty, 0)); 752 break; 753 } 754 755 case Intrinsic::dbg_stoppoint: 756 case Intrinsic::dbg_region_start: 757 case Intrinsic::dbg_region_end: 758 case Intrinsic::dbg_func_start: 759 case Intrinsic::dbg_declare: 760 break; // Simply strip out debugging intrinsics 761 762 case Intrinsic::eh_exception: 763 case Intrinsic::eh_selector_i32: 764 case Intrinsic::eh_selector_i64: 765 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 766 break; 767 768 case Intrinsic::eh_typeid_for_i32: 769 case Intrinsic::eh_typeid_for_i64: 770 // Return something different to eh_selector. 771 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1)); 772 break; 773 774 case Intrinsic::var_annotation: 775 break; // Strip out annotate intrinsic 776 777 case Intrinsic::memcpy: { 778 const IntegerType *IntPtr = TD.getIntPtrType(); 779 Value *Size = Builder.CreateIntCast(CI->getOperand(3), IntPtr, 780 /* isSigned */ false); 781 Value *Ops[3]; 782 Ops[0] = CI->getOperand(1); 783 Ops[1] = CI->getOperand(2); 784 Ops[2] = Size; 785 ReplaceCallWith("memcpy", CI, Ops, Ops+3, CI->getOperand(1)->getType()); 786 break; 787 } 788 case Intrinsic::memmove: { 789 const IntegerType *IntPtr = TD.getIntPtrType(); 790 Value *Size = Builder.CreateIntCast(CI->getOperand(3), IntPtr, 791 /* isSigned */ false); 792 Value *Ops[3]; 793 Ops[0] = CI->getOperand(1); 794 Ops[1] = CI->getOperand(2); 795 Ops[2] = Size; 796 ReplaceCallWith("memmove", CI, Ops, Ops+3, CI->getOperand(1)->getType()); 797 break; 798 } 799 case Intrinsic::memset: { 800 const IntegerType *IntPtr = TD.getIntPtrType(); 801 Value *Size = Builder.CreateIntCast(CI->getOperand(3), IntPtr, 802 /* isSigned */ false); 803 Value *Ops[3]; 804 Ops[0] = CI->getOperand(1); 805 // Extend the amount to i32. 806 Ops[1] = Builder.CreateIntCast(CI->getOperand(2), Type::Int32Ty, 807 /* isSigned */ false); 808 Ops[2] = Size; 809 ReplaceCallWith("memset", CI, Ops, Ops+3, CI->getOperand(1)->getType()); 810 break; 811 } 812 case Intrinsic::sqrt: { 813 ReplaceFPIntrinsicWithCall(CI, "sqrtf", "sqrt", "sqrtl"); 814 break; 815 } 816 case Intrinsic::log: { 817 ReplaceFPIntrinsicWithCall(CI, "logf", "log", "logl"); 818 break; 819 } 820 case Intrinsic::log2: { 821 ReplaceFPIntrinsicWithCall(CI, "log2f", "log2", "log2l"); 822 break; 823 } 824 case Intrinsic::log10: { 825 ReplaceFPIntrinsicWithCall(CI, "log10f", "log10", "log10l"); 826 break; 827 } 828 case Intrinsic::exp: { 829 ReplaceFPIntrinsicWithCall(CI, "expf", "exp", "expl"); 830 break; 831 } 832 case Intrinsic::exp2: { 833 ReplaceFPIntrinsicWithCall(CI, "exp2f", "exp2", "exp2l"); 834 break; 835 } 836 case Intrinsic::pow: { 837 ReplaceFPIntrinsicWithCall(CI, "powf", "pow", "powl"); 838 break; 839 } 840 case Intrinsic::flt_rounds: 841 // Lower to "round to the nearest" 842 if (CI->getType() != Type::VoidTy) 843 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1)); 844 break; 845 } 846 847 assert(CI->use_empty() && 848 "Lowering should have eliminated any uses of the intrinsic call!"); 849 CI->eraseFromParent(); 850} 851