InstCombineCalls.cpp revision 5e01f80bf85b9a68352d4c146caa9ddcf6af6dcf
1//===- InstCombineCalls.cpp -----------------------------------------------===// 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 visitCall and visitInvoke functions. 11// 12//===----------------------------------------------------------------------===// 13 14#include "InstCombine.h" 15#include "llvm/Support/CallSite.h" 16#include "llvm/DataLayout.h" 17#include "llvm/Analysis/MemoryBuiltins.h" 18#include "llvm/Transforms/Utils/BuildLibCalls.h" 19#include "llvm/Transforms/Utils/Local.h" 20using namespace llvm; 21 22/// getPromotedType - Return the specified type promoted as it would be to pass 23/// though a va_arg area. 24static Type *getPromotedType(Type *Ty) { 25 if (IntegerType* ITy = dyn_cast<IntegerType>(Ty)) { 26 if (ITy->getBitWidth() < 32) 27 return Type::getInt32Ty(Ty->getContext()); 28 } 29 return Ty; 30} 31 32/// reduceToSingleValueType - Given an aggregate type which ultimately holds a 33/// single scalar element, like {{{type}}} or [1 x type], return type. 34static Type *reduceToSingleValueType(Type *T) { 35 while (!T->isSingleValueType()) { 36 if (StructType *STy = dyn_cast<StructType>(T)) { 37 if (STy->getNumElements() == 1) 38 T = STy->getElementType(0); 39 else 40 break; 41 } else if (ArrayType *ATy = dyn_cast<ArrayType>(T)) { 42 if (ATy->getNumElements() == 1) 43 T = ATy->getElementType(); 44 else 45 break; 46 } else 47 break; 48 } 49 50 return T; 51} 52 53Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) { 54 unsigned DstAlign = getKnownAlignment(MI->getArgOperand(0), TD); 55 unsigned SrcAlign = getKnownAlignment(MI->getArgOperand(1), TD); 56 unsigned MinAlign = std::min(DstAlign, SrcAlign); 57 unsigned CopyAlign = MI->getAlignment(); 58 59 if (CopyAlign < MinAlign) { 60 MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 61 MinAlign, false)); 62 return MI; 63 } 64 65 // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with 66 // load/store. 67 ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getArgOperand(2)); 68 if (MemOpLength == 0) return 0; 69 70 // Source and destination pointer types are always "i8*" for intrinsic. See 71 // if the size is something we can handle with a single primitive load/store. 72 // A single load+store correctly handles overlapping memory in the memmove 73 // case. 74 uint64_t Size = MemOpLength->getLimitedValue(); 75 assert(Size && "0-sized memory transfering should be removed already."); 76 77 if (Size > 8 || (Size&(Size-1))) 78 return 0; // If not 1/2/4/8 bytes, exit. 79 80 // Use an integer load+store unless we can find something better. 81 unsigned SrcAddrSp = 82 cast<PointerType>(MI->getArgOperand(1)->getType())->getAddressSpace(); 83 unsigned DstAddrSp = 84 cast<PointerType>(MI->getArgOperand(0)->getType())->getAddressSpace(); 85 86 IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3); 87 Type *NewSrcPtrTy = PointerType::get(IntType, SrcAddrSp); 88 Type *NewDstPtrTy = PointerType::get(IntType, DstAddrSp); 89 90 // Memcpy forces the use of i8* for the source and destination. That means 91 // that if you're using memcpy to move one double around, you'll get a cast 92 // from double* to i8*. We'd much rather use a double load+store rather than 93 // an i64 load+store, here because this improves the odds that the source or 94 // dest address will be promotable. See if we can find a better type than the 95 // integer datatype. 96 Value *StrippedDest = MI->getArgOperand(0)->stripPointerCasts(); 97 MDNode *CopyMD = 0; 98 if (StrippedDest != MI->getArgOperand(0)) { 99 Type *SrcETy = cast<PointerType>(StrippedDest->getType()) 100 ->getElementType(); 101 if (TD && SrcETy->isSized() && TD->getTypeStoreSize(SrcETy) == Size) { 102 // The SrcETy might be something like {{{double}}} or [1 x double]. Rip 103 // down through these levels if so. 104 SrcETy = reduceToSingleValueType(SrcETy); 105 106 if (SrcETy->isSingleValueType()) { 107 NewSrcPtrTy = PointerType::get(SrcETy, SrcAddrSp); 108 NewDstPtrTy = PointerType::get(SrcETy, DstAddrSp); 109 110 // If the memcpy has metadata describing the members, see if we can 111 // get the TBAA tag describing our copy. 112 if (MDNode *M = MI->getMetadata(LLVMContext::MD_tbaa_struct)) { 113 if (M->getNumOperands() == 3 && 114 M->getOperand(0) && 115 isa<ConstantInt>(M->getOperand(0)) && 116 cast<ConstantInt>(M->getOperand(0))->isNullValue() && 117 M->getOperand(1) && 118 isa<ConstantInt>(M->getOperand(1)) && 119 cast<ConstantInt>(M->getOperand(1))->getValue() == Size && 120 M->getOperand(2) && 121 isa<MDNode>(M->getOperand(2))) 122 CopyMD = cast<MDNode>(M->getOperand(2)); 123 } 124 } 125 } 126 } 127 128 // If the memcpy/memmove provides better alignment info than we can 129 // infer, use it. 130 SrcAlign = std::max(SrcAlign, CopyAlign); 131 DstAlign = std::max(DstAlign, CopyAlign); 132 133 Value *Src = Builder->CreateBitCast(MI->getArgOperand(1), NewSrcPtrTy); 134 Value *Dest = Builder->CreateBitCast(MI->getArgOperand(0), NewDstPtrTy); 135 LoadInst *L = Builder->CreateLoad(Src, MI->isVolatile()); 136 L->setAlignment(SrcAlign); 137 if (CopyMD) 138 L->setMetadata(LLVMContext::MD_tbaa, CopyMD); 139 StoreInst *S = Builder->CreateStore(L, Dest, MI->isVolatile()); 140 S->setAlignment(DstAlign); 141 if (CopyMD) 142 S->setMetadata(LLVMContext::MD_tbaa, CopyMD); 143 144 // Set the size of the copy to 0, it will be deleted on the next iteration. 145 MI->setArgOperand(2, Constant::getNullValue(MemOpLength->getType())); 146 return MI; 147} 148 149Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) { 150 unsigned Alignment = getKnownAlignment(MI->getDest(), TD); 151 if (MI->getAlignment() < Alignment) { 152 MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 153 Alignment, false)); 154 return MI; 155 } 156 157 // Extract the length and alignment and fill if they are constant. 158 ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength()); 159 ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue()); 160 if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8)) 161 return 0; 162 uint64_t Len = LenC->getLimitedValue(); 163 Alignment = MI->getAlignment(); 164 assert(Len && "0-sized memory setting should be removed already."); 165 166 // memset(s,c,n) -> store s, c (for n=1,2,4,8) 167 if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) { 168 Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8. 169 170 Value *Dest = MI->getDest(); 171 unsigned DstAddrSp = cast<PointerType>(Dest->getType())->getAddressSpace(); 172 Type *NewDstPtrTy = PointerType::get(ITy, DstAddrSp); 173 Dest = Builder->CreateBitCast(Dest, NewDstPtrTy); 174 175 // Alignment 0 is identity for alignment 1 for memset, but not store. 176 if (Alignment == 0) Alignment = 1; 177 178 // Extract the fill value and store. 179 uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL; 180 StoreInst *S = Builder->CreateStore(ConstantInt::get(ITy, Fill), Dest, 181 MI->isVolatile()); 182 S->setAlignment(Alignment); 183 184 // Set the size of the copy to 0, it will be deleted on the next iteration. 185 MI->setLength(Constant::getNullValue(LenC->getType())); 186 return MI; 187 } 188 189 return 0; 190} 191 192/// visitCallInst - CallInst simplification. This mostly only handles folding 193/// of intrinsic instructions. For normal calls, it allows visitCallSite to do 194/// the heavy lifting. 195/// 196Instruction *InstCombiner::visitCallInst(CallInst &CI) { 197 if (isFreeCall(&CI, TLI)) 198 return visitFree(CI); 199 200 // If the caller function is nounwind, mark the call as nounwind, even if the 201 // callee isn't. 202 if (CI.getParent()->getParent()->doesNotThrow() && 203 !CI.doesNotThrow()) { 204 CI.setDoesNotThrow(); 205 return &CI; 206 } 207 208 IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI); 209 if (!II) return visitCallSite(&CI); 210 211 // Intrinsics cannot occur in an invoke, so handle them here instead of in 212 // visitCallSite. 213 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) { 214 bool Changed = false; 215 216 // memmove/cpy/set of zero bytes is a noop. 217 if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) { 218 if (NumBytes->isNullValue()) 219 return EraseInstFromFunction(CI); 220 221 if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes)) 222 if (CI->getZExtValue() == 1) { 223 // Replace the instruction with just byte operations. We would 224 // transform other cases to loads/stores, but we don't know if 225 // alignment is sufficient. 226 } 227 } 228 229 // No other transformations apply to volatile transfers. 230 if (MI->isVolatile()) 231 return 0; 232 233 // If we have a memmove and the source operation is a constant global, 234 // then the source and dest pointers can't alias, so we can change this 235 // into a call to memcpy. 236 if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) { 237 if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource())) 238 if (GVSrc->isConstant()) { 239 Module *M = CI.getParent()->getParent()->getParent(); 240 Intrinsic::ID MemCpyID = Intrinsic::memcpy; 241 Type *Tys[3] = { CI.getArgOperand(0)->getType(), 242 CI.getArgOperand(1)->getType(), 243 CI.getArgOperand(2)->getType() }; 244 CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys)); 245 Changed = true; 246 } 247 } 248 249 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) { 250 // memmove(x,x,size) -> noop. 251 if (MTI->getSource() == MTI->getDest()) 252 return EraseInstFromFunction(CI); 253 } 254 255 // If we can determine a pointer alignment that is bigger than currently 256 // set, update the alignment. 257 if (isa<MemTransferInst>(MI)) { 258 if (Instruction *I = SimplifyMemTransfer(MI)) 259 return I; 260 } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) { 261 if (Instruction *I = SimplifyMemSet(MSI)) 262 return I; 263 } 264 265 if (Changed) return II; 266 } 267 268 switch (II->getIntrinsicID()) { 269 default: break; 270 case Intrinsic::objectsize: { 271 uint64_t Size; 272 if (getObjectSize(II->getArgOperand(0), Size, TD, TLI)) 273 return ReplaceInstUsesWith(CI, ConstantInt::get(CI.getType(), Size)); 274 return 0; 275 } 276 case Intrinsic::bswap: 277 // bswap(bswap(x)) -> x 278 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) 279 if (Operand->getIntrinsicID() == Intrinsic::bswap) 280 return ReplaceInstUsesWith(CI, Operand->getArgOperand(0)); 281 282 // bswap(trunc(bswap(x))) -> trunc(lshr(x, c)) 283 if (TruncInst *TI = dyn_cast<TruncInst>(II->getArgOperand(0))) { 284 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0))) 285 if (Operand->getIntrinsicID() == Intrinsic::bswap) { 286 unsigned C = Operand->getType()->getPrimitiveSizeInBits() - 287 TI->getType()->getPrimitiveSizeInBits(); 288 Value *CV = ConstantInt::get(Operand->getType(), C); 289 Value *V = Builder->CreateLShr(Operand->getArgOperand(0), CV); 290 return new TruncInst(V, TI->getType()); 291 } 292 } 293 294 break; 295 case Intrinsic::powi: 296 if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 297 // powi(x, 0) -> 1.0 298 if (Power->isZero()) 299 return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0)); 300 // powi(x, 1) -> x 301 if (Power->isOne()) 302 return ReplaceInstUsesWith(CI, II->getArgOperand(0)); 303 // powi(x, -1) -> 1/x 304 if (Power->isAllOnesValue()) 305 return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0), 306 II->getArgOperand(0)); 307 } 308 break; 309 case Intrinsic::cttz: { 310 // If all bits below the first known one are known zero, 311 // this value is constant. 312 IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType()); 313 // FIXME: Try to simplify vectors of integers. 314 if (!IT) break; 315 uint32_t BitWidth = IT->getBitWidth(); 316 APInt KnownZero(BitWidth, 0); 317 APInt KnownOne(BitWidth, 0); 318 ComputeMaskedBits(II->getArgOperand(0), KnownZero, KnownOne); 319 unsigned TrailingZeros = KnownOne.countTrailingZeros(); 320 APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros)); 321 if ((Mask & KnownZero) == Mask) 322 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 323 APInt(BitWidth, TrailingZeros))); 324 325 } 326 break; 327 case Intrinsic::ctlz: { 328 // If all bits above the first known one are known zero, 329 // this value is constant. 330 IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType()); 331 // FIXME: Try to simplify vectors of integers. 332 if (!IT) break; 333 uint32_t BitWidth = IT->getBitWidth(); 334 APInt KnownZero(BitWidth, 0); 335 APInt KnownOne(BitWidth, 0); 336 ComputeMaskedBits(II->getArgOperand(0), KnownZero, KnownOne); 337 unsigned LeadingZeros = KnownOne.countLeadingZeros(); 338 APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros)); 339 if ((Mask & KnownZero) == Mask) 340 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 341 APInt(BitWidth, LeadingZeros))); 342 343 } 344 break; 345 case Intrinsic::uadd_with_overflow: { 346 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 347 IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 348 uint32_t BitWidth = IT->getBitWidth(); 349 APInt LHSKnownZero(BitWidth, 0); 350 APInt LHSKnownOne(BitWidth, 0); 351 ComputeMaskedBits(LHS, LHSKnownZero, LHSKnownOne); 352 bool LHSKnownNegative = LHSKnownOne[BitWidth - 1]; 353 bool LHSKnownPositive = LHSKnownZero[BitWidth - 1]; 354 355 if (LHSKnownNegative || LHSKnownPositive) { 356 APInt RHSKnownZero(BitWidth, 0); 357 APInt RHSKnownOne(BitWidth, 0); 358 ComputeMaskedBits(RHS, RHSKnownZero, RHSKnownOne); 359 bool RHSKnownNegative = RHSKnownOne[BitWidth - 1]; 360 bool RHSKnownPositive = RHSKnownZero[BitWidth - 1]; 361 if (LHSKnownNegative && RHSKnownNegative) { 362 // The sign bit is set in both cases: this MUST overflow. 363 // Create a simple add instruction, and insert it into the struct. 364 Value *Add = Builder->CreateAdd(LHS, RHS); 365 Add->takeName(&CI); 366 Constant *V[] = { 367 UndefValue::get(LHS->getType()), 368 ConstantInt::getTrue(II->getContext()) 369 }; 370 StructType *ST = cast<StructType>(II->getType()); 371 Constant *Struct = ConstantStruct::get(ST, V); 372 return InsertValueInst::Create(Struct, Add, 0); 373 } 374 375 if (LHSKnownPositive && RHSKnownPositive) { 376 // The sign bit is clear in both cases: this CANNOT overflow. 377 // Create a simple add instruction, and insert it into the struct. 378 Value *Add = Builder->CreateNUWAdd(LHS, RHS); 379 Add->takeName(&CI); 380 Constant *V[] = { 381 UndefValue::get(LHS->getType()), 382 ConstantInt::getFalse(II->getContext()) 383 }; 384 StructType *ST = cast<StructType>(II->getType()); 385 Constant *Struct = ConstantStruct::get(ST, V); 386 return InsertValueInst::Create(Struct, Add, 0); 387 } 388 } 389 } 390 // FALL THROUGH uadd into sadd 391 case Intrinsic::sadd_with_overflow: 392 // Canonicalize constants into the RHS. 393 if (isa<Constant>(II->getArgOperand(0)) && 394 !isa<Constant>(II->getArgOperand(1))) { 395 Value *LHS = II->getArgOperand(0); 396 II->setArgOperand(0, II->getArgOperand(1)); 397 II->setArgOperand(1, LHS); 398 return II; 399 } 400 401 // X + undef -> undef 402 if (isa<UndefValue>(II->getArgOperand(1))) 403 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 404 405 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 406 // X + 0 -> {X, false} 407 if (RHS->isZero()) { 408 Constant *V[] = { 409 UndefValue::get(II->getArgOperand(0)->getType()), 410 ConstantInt::getFalse(II->getContext()) 411 }; 412 Constant *Struct = 413 ConstantStruct::get(cast<StructType>(II->getType()), V); 414 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 415 } 416 } 417 break; 418 case Intrinsic::usub_with_overflow: 419 case Intrinsic::ssub_with_overflow: 420 // undef - X -> undef 421 // X - undef -> undef 422 if (isa<UndefValue>(II->getArgOperand(0)) || 423 isa<UndefValue>(II->getArgOperand(1))) 424 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 425 426 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 427 // X - 0 -> {X, false} 428 if (RHS->isZero()) { 429 Constant *V[] = { 430 UndefValue::get(II->getArgOperand(0)->getType()), 431 ConstantInt::getFalse(II->getContext()) 432 }; 433 Constant *Struct = 434 ConstantStruct::get(cast<StructType>(II->getType()), V); 435 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 436 } 437 } 438 break; 439 case Intrinsic::umul_with_overflow: { 440 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 441 unsigned BitWidth = cast<IntegerType>(LHS->getType())->getBitWidth(); 442 443 APInt LHSKnownZero(BitWidth, 0); 444 APInt LHSKnownOne(BitWidth, 0); 445 ComputeMaskedBits(LHS, LHSKnownZero, LHSKnownOne); 446 APInt RHSKnownZero(BitWidth, 0); 447 APInt RHSKnownOne(BitWidth, 0); 448 ComputeMaskedBits(RHS, RHSKnownZero, RHSKnownOne); 449 450 // Get the largest possible values for each operand. 451 APInt LHSMax = ~LHSKnownZero; 452 APInt RHSMax = ~RHSKnownZero; 453 454 // If multiplying the maximum values does not overflow then we can turn 455 // this into a plain NUW mul. 456 bool Overflow; 457 LHSMax.umul_ov(RHSMax, Overflow); 458 if (!Overflow) { 459 Value *Mul = Builder->CreateNUWMul(LHS, RHS, "umul_with_overflow"); 460 Constant *V[] = { 461 UndefValue::get(LHS->getType()), 462 Builder->getFalse() 463 }; 464 Constant *Struct = ConstantStruct::get(cast<StructType>(II->getType()),V); 465 return InsertValueInst::Create(Struct, Mul, 0); 466 } 467 } // FALL THROUGH 468 case Intrinsic::smul_with_overflow: 469 // Canonicalize constants into the RHS. 470 if (isa<Constant>(II->getArgOperand(0)) && 471 !isa<Constant>(II->getArgOperand(1))) { 472 Value *LHS = II->getArgOperand(0); 473 II->setArgOperand(0, II->getArgOperand(1)); 474 II->setArgOperand(1, LHS); 475 return II; 476 } 477 478 // X * undef -> undef 479 if (isa<UndefValue>(II->getArgOperand(1))) 480 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 481 482 if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 483 // X*0 -> {0, false} 484 if (RHSI->isZero()) 485 return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType())); 486 487 // X * 1 -> {X, false} 488 if (RHSI->equalsInt(1)) { 489 Constant *V[] = { 490 UndefValue::get(II->getArgOperand(0)->getType()), 491 ConstantInt::getFalse(II->getContext()) 492 }; 493 Constant *Struct = 494 ConstantStruct::get(cast<StructType>(II->getType()), V); 495 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 496 } 497 } 498 break; 499 case Intrinsic::ppc_altivec_lvx: 500 case Intrinsic::ppc_altivec_lvxl: 501 // Turn PPC lvx -> load if the pointer is known aligned. 502 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 503 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), 504 PointerType::getUnqual(II->getType())); 505 return new LoadInst(Ptr); 506 } 507 break; 508 case Intrinsic::ppc_altivec_stvx: 509 case Intrinsic::ppc_altivec_stvxl: 510 // Turn stvx -> store if the pointer is known aligned. 511 if (getOrEnforceKnownAlignment(II->getArgOperand(1), 16, TD) >= 16) { 512 Type *OpPtrTy = 513 PointerType::getUnqual(II->getArgOperand(0)->getType()); 514 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy); 515 return new StoreInst(II->getArgOperand(0), Ptr); 516 } 517 break; 518 case Intrinsic::x86_sse_storeu_ps: 519 case Intrinsic::x86_sse2_storeu_pd: 520 case Intrinsic::x86_sse2_storeu_dq: 521 // Turn X86 storeu -> store if the pointer is known aligned. 522 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 523 Type *OpPtrTy = 524 PointerType::getUnqual(II->getArgOperand(1)->getType()); 525 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy); 526 return new StoreInst(II->getArgOperand(1), Ptr); 527 } 528 break; 529 530 case Intrinsic::x86_sse_cvtss2si: 531 case Intrinsic::x86_sse_cvtss2si64: 532 case Intrinsic::x86_sse_cvttss2si: 533 case Intrinsic::x86_sse_cvttss2si64: 534 case Intrinsic::x86_sse2_cvtsd2si: 535 case Intrinsic::x86_sse2_cvtsd2si64: 536 case Intrinsic::x86_sse2_cvttsd2si: 537 case Intrinsic::x86_sse2_cvttsd2si64: { 538 // These intrinsics only demand the 0th element of their input vectors. If 539 // we can simplify the input based on that, do so now. 540 unsigned VWidth = 541 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 542 APInt DemandedElts(VWidth, 1); 543 APInt UndefElts(VWidth, 0); 544 if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0), 545 DemandedElts, UndefElts)) { 546 II->setArgOperand(0, V); 547 return II; 548 } 549 break; 550 } 551 552 553 case Intrinsic::x86_sse41_pmovsxbw: 554 case Intrinsic::x86_sse41_pmovsxwd: 555 case Intrinsic::x86_sse41_pmovsxdq: 556 case Intrinsic::x86_sse41_pmovzxbw: 557 case Intrinsic::x86_sse41_pmovzxwd: 558 case Intrinsic::x86_sse41_pmovzxdq: { 559 // pmov{s|z}x ignores the upper half of their input vectors. 560 unsigned VWidth = 561 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 562 unsigned LowHalfElts = VWidth / 2; 563 APInt InputDemandedElts(APInt::getBitsSet(VWidth, 0, LowHalfElts)); 564 APInt UndefElts(VWidth, 0); 565 if (Value *TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0), 566 InputDemandedElts, 567 UndefElts)) { 568 II->setArgOperand(0, TmpV); 569 return II; 570 } 571 break; 572 } 573 574 case Intrinsic::ppc_altivec_vperm: 575 // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant. 576 if (Constant *Mask = dyn_cast<Constant>(II->getArgOperand(2))) { 577 assert(Mask->getType()->getVectorNumElements() == 16 && 578 "Bad type for intrinsic!"); 579 580 // Check that all of the elements are integer constants or undefs. 581 bool AllEltsOk = true; 582 for (unsigned i = 0; i != 16; ++i) { 583 Constant *Elt = Mask->getAggregateElement(i); 584 if (Elt == 0 || 585 !(isa<ConstantInt>(Elt) || isa<UndefValue>(Elt))) { 586 AllEltsOk = false; 587 break; 588 } 589 } 590 591 if (AllEltsOk) { 592 // Cast the input vectors to byte vectors. 593 Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0), 594 Mask->getType()); 595 Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1), 596 Mask->getType()); 597 Value *Result = UndefValue::get(Op0->getType()); 598 599 // Only extract each element once. 600 Value *ExtractedElts[32]; 601 memset(ExtractedElts, 0, sizeof(ExtractedElts)); 602 603 for (unsigned i = 0; i != 16; ++i) { 604 if (isa<UndefValue>(Mask->getAggregateElement(i))) 605 continue; 606 unsigned Idx = 607 cast<ConstantInt>(Mask->getAggregateElement(i))->getZExtValue(); 608 Idx &= 31; // Match the hardware behavior. 609 610 if (ExtractedElts[Idx] == 0) { 611 ExtractedElts[Idx] = 612 Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1, 613 Builder->getInt32(Idx&15)); 614 } 615 616 // Insert this value into the result vector. 617 Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx], 618 Builder->getInt32(i)); 619 } 620 return CastInst::Create(Instruction::BitCast, Result, CI.getType()); 621 } 622 } 623 break; 624 625 case Intrinsic::arm_neon_vld1: 626 case Intrinsic::arm_neon_vld2: 627 case Intrinsic::arm_neon_vld3: 628 case Intrinsic::arm_neon_vld4: 629 case Intrinsic::arm_neon_vld2lane: 630 case Intrinsic::arm_neon_vld3lane: 631 case Intrinsic::arm_neon_vld4lane: 632 case Intrinsic::arm_neon_vst1: 633 case Intrinsic::arm_neon_vst2: 634 case Intrinsic::arm_neon_vst3: 635 case Intrinsic::arm_neon_vst4: 636 case Intrinsic::arm_neon_vst2lane: 637 case Intrinsic::arm_neon_vst3lane: 638 case Intrinsic::arm_neon_vst4lane: { 639 unsigned MemAlign = getKnownAlignment(II->getArgOperand(0), TD); 640 unsigned AlignArg = II->getNumArgOperands() - 1; 641 ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg)); 642 if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) { 643 II->setArgOperand(AlignArg, 644 ConstantInt::get(Type::getInt32Ty(II->getContext()), 645 MemAlign, false)); 646 return II; 647 } 648 break; 649 } 650 651 case Intrinsic::arm_neon_vmulls: 652 case Intrinsic::arm_neon_vmullu: { 653 Value *Arg0 = II->getArgOperand(0); 654 Value *Arg1 = II->getArgOperand(1); 655 656 // Handle mul by zero first: 657 if (isa<ConstantAggregateZero>(Arg0) || isa<ConstantAggregateZero>(Arg1)) { 658 return ReplaceInstUsesWith(CI, ConstantAggregateZero::get(II->getType())); 659 } 660 661 // Check for constant LHS & RHS - in this case we just simplify. 662 bool Zext = (II->getIntrinsicID() == Intrinsic::arm_neon_vmullu); 663 VectorType *NewVT = cast<VectorType>(II->getType()); 664 unsigned NewWidth = NewVT->getElementType()->getIntegerBitWidth(); 665 if (ConstantDataVector *CV0 = dyn_cast<ConstantDataVector>(Arg0)) { 666 if (ConstantDataVector *CV1 = dyn_cast<ConstantDataVector>(Arg1)) { 667 VectorType* VT = cast<VectorType>(CV0->getType()); 668 SmallVector<Constant*, 4> NewElems; 669 for (unsigned i = 0; i < VT->getNumElements(); ++i) { 670 APInt CV0E = 671 (cast<ConstantInt>(CV0->getAggregateElement(i)))->getValue(); 672 CV0E = Zext ? CV0E.zext(NewWidth) : CV0E.sext(NewWidth); 673 APInt CV1E = 674 (cast<ConstantInt>(CV1->getAggregateElement(i)))->getValue(); 675 CV1E = Zext ? CV1E.zext(NewWidth) : CV1E.sext(NewWidth); 676 NewElems.push_back( 677 ConstantInt::get(NewVT->getElementType(), CV0E * CV1E)); 678 } 679 return ReplaceInstUsesWith(CI, ConstantVector::get(NewElems)); 680 } 681 682 // Couldn't simplify - cannonicalize constant to the RHS. 683 std::swap(Arg0, Arg1); 684 } 685 686 // Handle mul by one: 687 if (ConstantDataVector *CV1 = dyn_cast<ConstantDataVector>(Arg1)) { 688 if (ConstantInt *Splat = 689 dyn_cast_or_null<ConstantInt>(CV1->getSplatValue())) { 690 if (Splat->isOne()) { 691 if (Zext) 692 return CastInst::CreateZExtOrBitCast(Arg0, II->getType()); 693 // else 694 return CastInst::CreateSExtOrBitCast(Arg0, II->getType()); 695 } 696 } 697 } 698 699 break; 700 } 701 702 case Intrinsic::stackrestore: { 703 // If the save is right next to the restore, remove the restore. This can 704 // happen when variable allocas are DCE'd. 705 if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 706 if (SS->getIntrinsicID() == Intrinsic::stacksave) { 707 BasicBlock::iterator BI = SS; 708 if (&*++BI == II) 709 return EraseInstFromFunction(CI); 710 } 711 } 712 713 // Scan down this block to see if there is another stack restore in the 714 // same block without an intervening call/alloca. 715 BasicBlock::iterator BI = II; 716 TerminatorInst *TI = II->getParent()->getTerminator(); 717 bool CannotRemove = false; 718 for (++BI; &*BI != TI; ++BI) { 719 if (isa<AllocaInst>(BI)) { 720 CannotRemove = true; 721 break; 722 } 723 if (CallInst *BCI = dyn_cast<CallInst>(BI)) { 724 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) { 725 // If there is a stackrestore below this one, remove this one. 726 if (II->getIntrinsicID() == Intrinsic::stackrestore) 727 return EraseInstFromFunction(CI); 728 // Otherwise, ignore the intrinsic. 729 } else { 730 // If we found a non-intrinsic call, we can't remove the stack 731 // restore. 732 CannotRemove = true; 733 break; 734 } 735 } 736 } 737 738 // If the stack restore is in a return, resume, or unwind block and if there 739 // are no allocas or calls between the restore and the return, nuke the 740 // restore. 741 if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI))) 742 return EraseInstFromFunction(CI); 743 break; 744 } 745 } 746 747 return visitCallSite(II); 748} 749 750// InvokeInst simplification 751// 752Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) { 753 return visitCallSite(&II); 754} 755 756/// isSafeToEliminateVarargsCast - If this cast does not affect the value 757/// passed through the varargs area, we can eliminate the use of the cast. 758static bool isSafeToEliminateVarargsCast(const CallSite CS, 759 const CastInst * const CI, 760 const DataLayout * const TD, 761 const int ix) { 762 if (!CI->isLosslessCast()) 763 return false; 764 765 // The size of ByVal arguments is derived from the type, so we 766 // can't change to a type with a different size. If the size were 767 // passed explicitly we could avoid this check. 768 if (!CS.isByValArgument(ix)) 769 return true; 770 771 Type* SrcTy = 772 cast<PointerType>(CI->getOperand(0)->getType())->getElementType(); 773 Type* DstTy = cast<PointerType>(CI->getType())->getElementType(); 774 if (!SrcTy->isSized() || !DstTy->isSized()) 775 return false; 776 if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy)) 777 return false; 778 return true; 779} 780 781namespace { 782class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls { 783 InstCombiner *IC; 784protected: 785 void replaceCall(Value *With) { 786 NewInstruction = IC->ReplaceInstUsesWith(*CI, With); 787 } 788 bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const { 789 if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp)) 790 return true; 791 if (ConstantInt *SizeCI = 792 dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) { 793 if (SizeCI->isAllOnesValue()) 794 return true; 795 if (isString) { 796 uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp)); 797 // If the length is 0 we don't know how long it is and so we can't 798 // remove the check. 799 if (Len == 0) return false; 800 return SizeCI->getZExtValue() >= Len; 801 } 802 if (ConstantInt *Arg = dyn_cast<ConstantInt>( 803 CI->getArgOperand(SizeArgOp))) 804 return SizeCI->getZExtValue() >= Arg->getZExtValue(); 805 } 806 return false; 807 } 808public: 809 InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { } 810 Instruction *NewInstruction; 811}; 812} // end anonymous namespace 813 814// Try to fold some different type of calls here. 815// Currently we're only working with the checking functions, memcpy_chk, 816// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk, 817// strcat_chk and strncat_chk. 818Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const DataLayout *TD) { 819 if (CI->getCalledFunction() == 0) return 0; 820 821 InstCombineFortifiedLibCalls Simplifier(this); 822 Simplifier.fold(CI, TD, TLI); 823 return Simplifier.NewInstruction; 824} 825 826static IntrinsicInst *FindInitTrampolineFromAlloca(Value *TrampMem) { 827 // Strip off at most one level of pointer casts, looking for an alloca. This 828 // is good enough in practice and simpler than handling any number of casts. 829 Value *Underlying = TrampMem->stripPointerCasts(); 830 if (Underlying != TrampMem && 831 (!Underlying->hasOneUse() || *Underlying->use_begin() != TrampMem)) 832 return 0; 833 if (!isa<AllocaInst>(Underlying)) 834 return 0; 835 836 IntrinsicInst *InitTrampoline = 0; 837 for (Value::use_iterator I = TrampMem->use_begin(), E = TrampMem->use_end(); 838 I != E; I++) { 839 IntrinsicInst *II = dyn_cast<IntrinsicInst>(*I); 840 if (!II) 841 return 0; 842 if (II->getIntrinsicID() == Intrinsic::init_trampoline) { 843 if (InitTrampoline) 844 // More than one init_trampoline writes to this value. Give up. 845 return 0; 846 InitTrampoline = II; 847 continue; 848 } 849 if (II->getIntrinsicID() == Intrinsic::adjust_trampoline) 850 // Allow any number of calls to adjust.trampoline. 851 continue; 852 return 0; 853 } 854 855 // No call to init.trampoline found. 856 if (!InitTrampoline) 857 return 0; 858 859 // Check that the alloca is being used in the expected way. 860 if (InitTrampoline->getOperand(0) != TrampMem) 861 return 0; 862 863 return InitTrampoline; 864} 865 866static IntrinsicInst *FindInitTrampolineFromBB(IntrinsicInst *AdjustTramp, 867 Value *TrampMem) { 868 // Visit all the previous instructions in the basic block, and try to find a 869 // init.trampoline which has a direct path to the adjust.trampoline. 870 for (BasicBlock::iterator I = AdjustTramp, 871 E = AdjustTramp->getParent()->begin(); I != E; ) { 872 Instruction *Inst = --I; 873 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) 874 if (II->getIntrinsicID() == Intrinsic::init_trampoline && 875 II->getOperand(0) == TrampMem) 876 return II; 877 if (Inst->mayWriteToMemory()) 878 return 0; 879 } 880 return 0; 881} 882 883// Given a call to llvm.adjust.trampoline, find and return the corresponding 884// call to llvm.init.trampoline if the call to the trampoline can be optimized 885// to a direct call to a function. Otherwise return NULL. 886// 887static IntrinsicInst *FindInitTrampoline(Value *Callee) { 888 Callee = Callee->stripPointerCasts(); 889 IntrinsicInst *AdjustTramp = dyn_cast<IntrinsicInst>(Callee); 890 if (!AdjustTramp || 891 AdjustTramp->getIntrinsicID() != Intrinsic::adjust_trampoline) 892 return 0; 893 894 Value *TrampMem = AdjustTramp->getOperand(0); 895 896 if (IntrinsicInst *IT = FindInitTrampolineFromAlloca(TrampMem)) 897 return IT; 898 if (IntrinsicInst *IT = FindInitTrampolineFromBB(AdjustTramp, TrampMem)) 899 return IT; 900 return 0; 901} 902 903// visitCallSite - Improvements for call and invoke instructions. 904// 905Instruction *InstCombiner::visitCallSite(CallSite CS) { 906 if (isAllocLikeFn(CS.getInstruction(), TLI)) 907 return visitAllocSite(*CS.getInstruction()); 908 909 bool Changed = false; 910 911 // If the callee is a pointer to a function, attempt to move any casts to the 912 // arguments of the call/invoke. 913 Value *Callee = CS.getCalledValue(); 914 if (!isa<Function>(Callee) && transformConstExprCastCall(CS)) 915 return 0; 916 917 if (Function *CalleeF = dyn_cast<Function>(Callee)) 918 // If the call and callee calling conventions don't match, this call must 919 // be unreachable, as the call is undefined. 920 if (CalleeF->getCallingConv() != CS.getCallingConv() && 921 // Only do this for calls to a function with a body. A prototype may 922 // not actually end up matching the implementation's calling conv for a 923 // variety of reasons (e.g. it may be written in assembly). 924 !CalleeF->isDeclaration()) { 925 Instruction *OldCall = CS.getInstruction(); 926 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 927 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 928 OldCall); 929 // If OldCall dues not return void then replaceAllUsesWith undef. 930 // This allows ValueHandlers and custom metadata to adjust itself. 931 if (!OldCall->getType()->isVoidTy()) 932 ReplaceInstUsesWith(*OldCall, UndefValue::get(OldCall->getType())); 933 if (isa<CallInst>(OldCall)) 934 return EraseInstFromFunction(*OldCall); 935 936 // We cannot remove an invoke, because it would change the CFG, just 937 // change the callee to a null pointer. 938 cast<InvokeInst>(OldCall)->setCalledFunction( 939 Constant::getNullValue(CalleeF->getType())); 940 return 0; 941 } 942 943 if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) { 944 // If CS does not return void then replaceAllUsesWith undef. 945 // This allows ValueHandlers and custom metadata to adjust itself. 946 if (!CS.getInstruction()->getType()->isVoidTy()) 947 ReplaceInstUsesWith(*CS.getInstruction(), 948 UndefValue::get(CS.getInstruction()->getType())); 949 950 if (isa<InvokeInst>(CS.getInstruction())) { 951 // Can't remove an invoke because we cannot change the CFG. 952 return 0; 953 } 954 955 // This instruction is not reachable, just remove it. We insert a store to 956 // undef so that we know that this code is not reachable, despite the fact 957 // that we can't modify the CFG here. 958 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 959 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 960 CS.getInstruction()); 961 962 return EraseInstFromFunction(*CS.getInstruction()); 963 } 964 965 if (IntrinsicInst *II = FindInitTrampoline(Callee)) 966 return transformCallThroughTrampoline(CS, II); 967 968 PointerType *PTy = cast<PointerType>(Callee->getType()); 969 FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 970 if (FTy->isVarArg()) { 971 int ix = FTy->getNumParams(); 972 // See if we can optimize any arguments passed through the varargs area of 973 // the call. 974 for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(), 975 E = CS.arg_end(); I != E; ++I, ++ix) { 976 CastInst *CI = dyn_cast<CastInst>(*I); 977 if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) { 978 *I = CI->getOperand(0); 979 Changed = true; 980 } 981 } 982 } 983 984 if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) { 985 // Inline asm calls cannot throw - mark them 'nounwind'. 986 CS.setDoesNotThrow(); 987 Changed = true; 988 } 989 990 // Try to optimize the call if possible, we require DataLayout for most of 991 // this. None of these calls are seen as possibly dead so go ahead and 992 // delete the instruction now. 993 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) { 994 Instruction *I = tryOptimizeCall(CI, TD); 995 // If we changed something return the result, etc. Otherwise let 996 // the fallthrough check. 997 if (I) return EraseInstFromFunction(*I); 998 } 999 1000 return Changed ? CS.getInstruction() : 0; 1001} 1002 1003// transformConstExprCastCall - If the callee is a constexpr cast of a function, 1004// attempt to move the cast to the arguments of the call/invoke. 1005// 1006bool InstCombiner::transformConstExprCastCall(CallSite CS) { 1007 Function *Callee = 1008 dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); 1009 if (Callee == 0) 1010 return false; 1011 Instruction *Caller = CS.getInstruction(); 1012 const AttrListPtr &CallerPAL = CS.getAttributes(); 1013 1014 // Okay, this is a cast from a function to a different type. Unless doing so 1015 // would cause a type conversion of one of our arguments, change this call to 1016 // be a direct call with arguments casted to the appropriate types. 1017 // 1018 FunctionType *FT = Callee->getFunctionType(); 1019 Type *OldRetTy = Caller->getType(); 1020 Type *NewRetTy = FT->getReturnType(); 1021 1022 if (NewRetTy->isStructTy()) 1023 return false; // TODO: Handle multiple return values. 1024 1025 // Check to see if we are changing the return type... 1026 if (OldRetTy != NewRetTy) { 1027 if (Callee->isDeclaration() && 1028 // Conversion is ok if changing from one pointer type to another or from 1029 // a pointer to an integer of the same size. 1030 !((OldRetTy->isPointerTy() || !TD || 1031 OldRetTy == TD->getIntPtrType(Caller->getContext())) && 1032 (NewRetTy->isPointerTy() || !TD || 1033 NewRetTy == TD->getIntPtrType(Caller->getContext())))) 1034 return false; // Cannot transform this return value. 1035 1036 if (!Caller->use_empty() && 1037 // void -> non-void is handled specially 1038 !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy)) 1039 return false; // Cannot transform this return value. 1040 1041 if (!CallerPAL.isEmpty() && !Caller->use_empty()) { 1042 Attributes::Builder RAttrs = CallerPAL.getRetAttributes(); 1043 if (RAttrs.hasAttributes(Attributes::typeIncompatible(NewRetTy))) 1044 return false; // Attribute not compatible with transformed value. 1045 } 1046 1047 // If the callsite is an invoke instruction, and the return value is used by 1048 // a PHI node in a successor, we cannot change the return type of the call 1049 // because there is no place to put the cast instruction (without breaking 1050 // the critical edge). Bail out in this case. 1051 if (!Caller->use_empty()) 1052 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) 1053 for (Value::use_iterator UI = II->use_begin(), E = II->use_end(); 1054 UI != E; ++UI) 1055 if (PHINode *PN = dyn_cast<PHINode>(*UI)) 1056 if (PN->getParent() == II->getNormalDest() || 1057 PN->getParent() == II->getUnwindDest()) 1058 return false; 1059 } 1060 1061 unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin()); 1062 unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); 1063 1064 CallSite::arg_iterator AI = CS.arg_begin(); 1065 for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { 1066 Type *ParamTy = FT->getParamType(i); 1067 Type *ActTy = (*AI)->getType(); 1068 1069 if (!CastInst::isCastable(ActTy, ParamTy)) 1070 return false; // Cannot transform this parameter value. 1071 1072 Attributes Attrs = CallerPAL.getParamAttributes(i + 1); 1073 if (Attrs & Attributes::typeIncompatible(ParamTy)) 1074 return false; // Attribute not compatible with transformed value. 1075 1076 // If the parameter is passed as a byval argument, then we have to have a 1077 // sized type and the sized type has to have the same size as the old type. 1078 if (ParamTy != ActTy && Attrs.hasAttribute(Attributes::ByVal)) { 1079 PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy); 1080 if (ParamPTy == 0 || !ParamPTy->getElementType()->isSized() || TD == 0) 1081 return false; 1082 1083 Type *CurElTy = cast<PointerType>(ActTy)->getElementType(); 1084 if (TD->getTypeAllocSize(CurElTy) != 1085 TD->getTypeAllocSize(ParamPTy->getElementType())) 1086 return false; 1087 } 1088 1089 // Converting from one pointer type to another or between a pointer and an 1090 // integer of the same size is safe even if we do not have a body. 1091 bool isConvertible = ActTy == ParamTy || 1092 (TD && ((ParamTy->isPointerTy() || 1093 ParamTy == TD->getIntPtrType(Caller->getContext())) && 1094 (ActTy->isPointerTy() || 1095 ActTy == TD->getIntPtrType(Caller->getContext())))); 1096 if (Callee->isDeclaration() && !isConvertible) return false; 1097 } 1098 1099 if (Callee->isDeclaration()) { 1100 // Do not delete arguments unless we have a function body. 1101 if (FT->getNumParams() < NumActualArgs && !FT->isVarArg()) 1102 return false; 1103 1104 // If the callee is just a declaration, don't change the varargsness of the 1105 // call. We don't want to introduce a varargs call where one doesn't 1106 // already exist. 1107 PointerType *APTy = cast<PointerType>(CS.getCalledValue()->getType()); 1108 if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg()) 1109 return false; 1110 1111 // If both the callee and the cast type are varargs, we still have to make 1112 // sure the number of fixed parameters are the same or we have the same 1113 // ABI issues as if we introduce a varargs call. 1114 if (FT->isVarArg() && 1115 cast<FunctionType>(APTy->getElementType())->isVarArg() && 1116 FT->getNumParams() != 1117 cast<FunctionType>(APTy->getElementType())->getNumParams()) 1118 return false; 1119 } 1120 1121 if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && 1122 !CallerPAL.isEmpty()) 1123 // In this case we have more arguments than the new function type, but we 1124 // won't be dropping them. Check that these extra arguments have attributes 1125 // that are compatible with being a vararg call argument. 1126 for (unsigned i = CallerPAL.getNumSlots(); i; --i) { 1127 if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams()) 1128 break; 1129 Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs; 1130 if (PAttrs.hasIncompatibleWithVarArgsAttrs()) 1131 return false; 1132 } 1133 1134 1135 // Okay, we decided that this is a safe thing to do: go ahead and start 1136 // inserting cast instructions as necessary. 1137 std::vector<Value*> Args; 1138 Args.reserve(NumActualArgs); 1139 SmallVector<AttributeWithIndex, 8> attrVec; 1140 attrVec.reserve(NumCommonArgs); 1141 1142 // Get any return attributes. 1143 Attributes::Builder RAttrs = CallerPAL.getRetAttributes(); 1144 1145 // If the return value is not being used, the type may not be compatible 1146 // with the existing attributes. Wipe out any problematic attributes. 1147 RAttrs.removeAttributes(Attributes::typeIncompatible(NewRetTy)); 1148 1149 // Add the new return attributes. 1150 if (RAttrs.hasAttributes()) 1151 attrVec.push_back(AttributeWithIndex::get(0, Attributes::get(RAttrs))); 1152 1153 AI = CS.arg_begin(); 1154 for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { 1155 Type *ParamTy = FT->getParamType(i); 1156 if ((*AI)->getType() == ParamTy) { 1157 Args.push_back(*AI); 1158 } else { 1159 Instruction::CastOps opcode = CastInst::getCastOpcode(*AI, 1160 false, ParamTy, false); 1161 Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy)); 1162 } 1163 1164 // Add any parameter attributes. 1165 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1166 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1167 } 1168 1169 // If the function takes more arguments than the call was taking, add them 1170 // now. 1171 for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) 1172 Args.push_back(Constant::getNullValue(FT->getParamType(i))); 1173 1174 // If we are removing arguments to the function, emit an obnoxious warning. 1175 if (FT->getNumParams() < NumActualArgs) { 1176 if (!FT->isVarArg()) { 1177 errs() << "WARNING: While resolving call to function '" 1178 << Callee->getName() << "' arguments were dropped!\n"; 1179 } else { 1180 // Add all of the arguments in their promoted form to the arg list. 1181 for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { 1182 Type *PTy = getPromotedType((*AI)->getType()); 1183 if (PTy != (*AI)->getType()) { 1184 // Must promote to pass through va_arg area! 1185 Instruction::CastOps opcode = 1186 CastInst::getCastOpcode(*AI, false, PTy, false); 1187 Args.push_back(Builder->CreateCast(opcode, *AI, PTy)); 1188 } else { 1189 Args.push_back(*AI); 1190 } 1191 1192 // Add any parameter attributes. 1193 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1194 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1195 } 1196 } 1197 } 1198 1199 if (Attributes FnAttrs = CallerPAL.getFnAttributes()) 1200 attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs)); 1201 1202 if (NewRetTy->isVoidTy()) 1203 Caller->setName(""); // Void type should not have a name. 1204 1205 const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec); 1206 1207 Instruction *NC; 1208 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1209 NC = Builder->CreateInvoke(Callee, II->getNormalDest(), 1210 II->getUnwindDest(), Args); 1211 NC->takeName(II); 1212 cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv()); 1213 cast<InvokeInst>(NC)->setAttributes(NewCallerPAL); 1214 } else { 1215 CallInst *CI = cast<CallInst>(Caller); 1216 NC = Builder->CreateCall(Callee, Args); 1217 NC->takeName(CI); 1218 if (CI->isTailCall()) 1219 cast<CallInst>(NC)->setTailCall(); 1220 cast<CallInst>(NC)->setCallingConv(CI->getCallingConv()); 1221 cast<CallInst>(NC)->setAttributes(NewCallerPAL); 1222 } 1223 1224 // Insert a cast of the return type as necessary. 1225 Value *NV = NC; 1226 if (OldRetTy != NV->getType() && !Caller->use_empty()) { 1227 if (!NV->getType()->isVoidTy()) { 1228 Instruction::CastOps opcode = 1229 CastInst::getCastOpcode(NC, false, OldRetTy, false); 1230 NV = NC = CastInst::Create(opcode, NC, OldRetTy); 1231 NC->setDebugLoc(Caller->getDebugLoc()); 1232 1233 // If this is an invoke instruction, we should insert it after the first 1234 // non-phi, instruction in the normal successor block. 1235 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1236 BasicBlock::iterator I = II->getNormalDest()->getFirstInsertionPt(); 1237 InsertNewInstBefore(NC, *I); 1238 } else { 1239 // Otherwise, it's a call, just insert cast right after the call. 1240 InsertNewInstBefore(NC, *Caller); 1241 } 1242 Worklist.AddUsersToWorkList(*Caller); 1243 } else { 1244 NV = UndefValue::get(Caller->getType()); 1245 } 1246 } 1247 1248 if (!Caller->use_empty()) 1249 ReplaceInstUsesWith(*Caller, NV); 1250 1251 EraseInstFromFunction(*Caller); 1252 return true; 1253} 1254 1255// transformCallThroughTrampoline - Turn a call to a function created by 1256// init_trampoline / adjust_trampoline intrinsic pair into a direct call to the 1257// underlying function. 1258// 1259Instruction * 1260InstCombiner::transformCallThroughTrampoline(CallSite CS, 1261 IntrinsicInst *Tramp) { 1262 Value *Callee = CS.getCalledValue(); 1263 PointerType *PTy = cast<PointerType>(Callee->getType()); 1264 FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 1265 const AttrListPtr &Attrs = CS.getAttributes(); 1266 1267 // If the call already has the 'nest' attribute somewhere then give up - 1268 // otherwise 'nest' would occur twice after splicing in the chain. 1269 for (unsigned I = 0, E = Attrs.getNumAttrs(); I != E; ++I) 1270 if (Attrs.getAttributesAtIndex(I).hasAttribute(Attributes::Nest)) 1271 return 0; 1272 1273 assert(Tramp && 1274 "transformCallThroughTrampoline called with incorrect CallSite."); 1275 1276 Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts()); 1277 PointerType *NestFPTy = cast<PointerType>(NestF->getType()); 1278 FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType()); 1279 1280 const AttrListPtr &NestAttrs = NestF->getAttributes(); 1281 if (!NestAttrs.isEmpty()) { 1282 unsigned NestIdx = 1; 1283 Type *NestTy = 0; 1284 Attributes NestAttr; 1285 1286 // Look for a parameter marked with the 'nest' attribute. 1287 for (FunctionType::param_iterator I = NestFTy->param_begin(), 1288 E = NestFTy->param_end(); I != E; ++NestIdx, ++I) 1289 if (NestAttrs.getParamAttributes(NestIdx).hasAttribute(Attributes::Nest)){ 1290 // Record the parameter type and any other attributes. 1291 NestTy = *I; 1292 NestAttr = NestAttrs.getParamAttributes(NestIdx); 1293 break; 1294 } 1295 1296 if (NestTy) { 1297 Instruction *Caller = CS.getInstruction(); 1298 std::vector<Value*> NewArgs; 1299 NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1); 1300 1301 SmallVector<AttributeWithIndex, 8> NewAttrs; 1302 NewAttrs.reserve(Attrs.getNumSlots() + 1); 1303 1304 // Insert the nest argument into the call argument list, which may 1305 // mean appending it. Likewise for attributes. 1306 1307 // Add any result attributes. 1308 if (Attributes Attr = Attrs.getRetAttributes()) 1309 NewAttrs.push_back(AttributeWithIndex::get(0, Attr)); 1310 1311 { 1312 unsigned Idx = 1; 1313 CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); 1314 do { 1315 if (Idx == NestIdx) { 1316 // Add the chain argument and attributes. 1317 Value *NestVal = Tramp->getArgOperand(2); 1318 if (NestVal->getType() != NestTy) 1319 NestVal = Builder->CreateBitCast(NestVal, NestTy, "nest"); 1320 NewArgs.push_back(NestVal); 1321 NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr)); 1322 } 1323 1324 if (I == E) 1325 break; 1326 1327 // Add the original argument and attributes. 1328 NewArgs.push_back(*I); 1329 if (Attributes Attr = Attrs.getParamAttributes(Idx)) 1330 NewAttrs.push_back 1331 (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr)); 1332 1333 ++Idx, ++I; 1334 } while (1); 1335 } 1336 1337 // Add any function attributes. 1338 if (Attributes Attr = Attrs.getFnAttributes()) 1339 NewAttrs.push_back(AttributeWithIndex::get(~0, Attr)); 1340 1341 // The trampoline may have been bitcast to a bogus type (FTy). 1342 // Handle this by synthesizing a new function type, equal to FTy 1343 // with the chain parameter inserted. 1344 1345 std::vector<Type*> NewTypes; 1346 NewTypes.reserve(FTy->getNumParams()+1); 1347 1348 // Insert the chain's type into the list of parameter types, which may 1349 // mean appending it. 1350 { 1351 unsigned Idx = 1; 1352 FunctionType::param_iterator I = FTy->param_begin(), 1353 E = FTy->param_end(); 1354 1355 do { 1356 if (Idx == NestIdx) 1357 // Add the chain's type. 1358 NewTypes.push_back(NestTy); 1359 1360 if (I == E) 1361 break; 1362 1363 // Add the original type. 1364 NewTypes.push_back(*I); 1365 1366 ++Idx, ++I; 1367 } while (1); 1368 } 1369 1370 // Replace the trampoline call with a direct call. Let the generic 1371 // code sort out any function type mismatches. 1372 FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, 1373 FTy->isVarArg()); 1374 Constant *NewCallee = 1375 NestF->getType() == PointerType::getUnqual(NewFTy) ? 1376 NestF : ConstantExpr::getBitCast(NestF, 1377 PointerType::getUnqual(NewFTy)); 1378 const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs); 1379 1380 Instruction *NewCaller; 1381 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1382 NewCaller = InvokeInst::Create(NewCallee, 1383 II->getNormalDest(), II->getUnwindDest(), 1384 NewArgs); 1385 cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv()); 1386 cast<InvokeInst>(NewCaller)->setAttributes(NewPAL); 1387 } else { 1388 NewCaller = CallInst::Create(NewCallee, NewArgs); 1389 if (cast<CallInst>(Caller)->isTailCall()) 1390 cast<CallInst>(NewCaller)->setTailCall(); 1391 cast<CallInst>(NewCaller)-> 1392 setCallingConv(cast<CallInst>(Caller)->getCallingConv()); 1393 cast<CallInst>(NewCaller)->setAttributes(NewPAL); 1394 } 1395 1396 return NewCaller; 1397 } 1398 } 1399 1400 // Replace the trampoline call with a direct call. Since there is no 'nest' 1401 // parameter, there is no need to adjust the argument list. Let the generic 1402 // code sort out any function type mismatches. 1403 Constant *NewCallee = 1404 NestF->getType() == PTy ? NestF : 1405 ConstantExpr::getBitCast(NestF, PTy); 1406 CS.setCalledFunction(NewCallee); 1407 return CS.getInstruction(); 1408} 1409