InstCombineCalls.cpp revision 6765834754cbb3cb0f15b4b15e98c5e73fa50066
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 isa<ConstantInt>(M->getOperand(0)) && 115 cast<ConstantInt>(M->getOperand(0))->isNullValue() && 116 isa<ConstantInt>(M->getOperand(1)) && 117 cast<ConstantInt>(M->getOperand(1))->getValue() == Size && 118 isa<MDNode>(M->getOperand(2))) 119 CopyMD = cast<MDNode>(M->getOperand(2)); 120 } 121 } 122 } 123 } 124 125 // If the memcpy/memmove provides better alignment info than we can 126 // infer, use it. 127 SrcAlign = std::max(SrcAlign, CopyAlign); 128 DstAlign = std::max(DstAlign, CopyAlign); 129 130 Value *Src = Builder->CreateBitCast(MI->getArgOperand(1), NewSrcPtrTy); 131 Value *Dest = Builder->CreateBitCast(MI->getArgOperand(0), NewDstPtrTy); 132 LoadInst *L = Builder->CreateLoad(Src, MI->isVolatile()); 133 L->setAlignment(SrcAlign); 134 if (CopyMD) 135 L->setMetadata(LLVMContext::MD_tbaa, CopyMD); 136 StoreInst *S = Builder->CreateStore(L, Dest, MI->isVolatile()); 137 S->setAlignment(DstAlign); 138 if (CopyMD) 139 S->setMetadata(LLVMContext::MD_tbaa, CopyMD); 140 141 // Set the size of the copy to 0, it will be deleted on the next iteration. 142 MI->setArgOperand(2, Constant::getNullValue(MemOpLength->getType())); 143 return MI; 144} 145 146Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) { 147 unsigned Alignment = getKnownAlignment(MI->getDest(), TD); 148 if (MI->getAlignment() < Alignment) { 149 MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 150 Alignment, false)); 151 return MI; 152 } 153 154 // Extract the length and alignment and fill if they are constant. 155 ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength()); 156 ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue()); 157 if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8)) 158 return 0; 159 uint64_t Len = LenC->getLimitedValue(); 160 Alignment = MI->getAlignment(); 161 assert(Len && "0-sized memory setting should be removed already."); 162 163 // memset(s,c,n) -> store s, c (for n=1,2,4,8) 164 if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) { 165 Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8. 166 167 Value *Dest = MI->getDest(); 168 unsigned DstAddrSp = cast<PointerType>(Dest->getType())->getAddressSpace(); 169 Type *NewDstPtrTy = PointerType::get(ITy, DstAddrSp); 170 Dest = Builder->CreateBitCast(Dest, NewDstPtrTy); 171 172 // Alignment 0 is identity for alignment 1 for memset, but not store. 173 if (Alignment == 0) Alignment = 1; 174 175 // Extract the fill value and store. 176 uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL; 177 StoreInst *S = Builder->CreateStore(ConstantInt::get(ITy, Fill), Dest, 178 MI->isVolatile()); 179 S->setAlignment(Alignment); 180 181 // Set the size of the copy to 0, it will be deleted on the next iteration. 182 MI->setLength(Constant::getNullValue(LenC->getType())); 183 return MI; 184 } 185 186 return 0; 187} 188 189/// visitCallInst - CallInst simplification. This mostly only handles folding 190/// of intrinsic instructions. For normal calls, it allows visitCallSite to do 191/// the heavy lifting. 192/// 193Instruction *InstCombiner::visitCallInst(CallInst &CI) { 194 if (isFreeCall(&CI, TLI)) 195 return visitFree(CI); 196 197 // If the caller function is nounwind, mark the call as nounwind, even if the 198 // callee isn't. 199 if (CI.getParent()->getParent()->doesNotThrow() && 200 !CI.doesNotThrow()) { 201 CI.setDoesNotThrow(); 202 return &CI; 203 } 204 205 IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI); 206 if (!II) return visitCallSite(&CI); 207 208 // Intrinsics cannot occur in an invoke, so handle them here instead of in 209 // visitCallSite. 210 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) { 211 bool Changed = false; 212 213 // memmove/cpy/set of zero bytes is a noop. 214 if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) { 215 if (NumBytes->isNullValue()) 216 return EraseInstFromFunction(CI); 217 218 if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes)) 219 if (CI->getZExtValue() == 1) { 220 // Replace the instruction with just byte operations. We would 221 // transform other cases to loads/stores, but we don't know if 222 // alignment is sufficient. 223 } 224 } 225 226 // No other transformations apply to volatile transfers. 227 if (MI->isVolatile()) 228 return 0; 229 230 // If we have a memmove and the source operation is a constant global, 231 // then the source and dest pointers can't alias, so we can change this 232 // into a call to memcpy. 233 if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) { 234 if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource())) 235 if (GVSrc->isConstant()) { 236 Module *M = CI.getParent()->getParent()->getParent(); 237 Intrinsic::ID MemCpyID = Intrinsic::memcpy; 238 Type *Tys[3] = { CI.getArgOperand(0)->getType(), 239 CI.getArgOperand(1)->getType(), 240 CI.getArgOperand(2)->getType() }; 241 CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys)); 242 Changed = true; 243 } 244 } 245 246 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) { 247 // memmove(x,x,size) -> noop. 248 if (MTI->getSource() == MTI->getDest()) 249 return EraseInstFromFunction(CI); 250 } 251 252 // If we can determine a pointer alignment that is bigger than currently 253 // set, update the alignment. 254 if (isa<MemTransferInst>(MI)) { 255 if (Instruction *I = SimplifyMemTransfer(MI)) 256 return I; 257 } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) { 258 if (Instruction *I = SimplifyMemSet(MSI)) 259 return I; 260 } 261 262 if (Changed) return II; 263 } 264 265 switch (II->getIntrinsicID()) { 266 default: break; 267 case Intrinsic::objectsize: { 268 uint64_t Size; 269 if (getObjectSize(II->getArgOperand(0), Size, TD, TLI)) 270 return ReplaceInstUsesWith(CI, ConstantInt::get(CI.getType(), Size)); 271 return 0; 272 } 273 case Intrinsic::bswap: 274 // bswap(bswap(x)) -> x 275 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) 276 if (Operand->getIntrinsicID() == Intrinsic::bswap) 277 return ReplaceInstUsesWith(CI, Operand->getArgOperand(0)); 278 279 // bswap(trunc(bswap(x))) -> trunc(lshr(x, c)) 280 if (TruncInst *TI = dyn_cast<TruncInst>(II->getArgOperand(0))) { 281 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0))) 282 if (Operand->getIntrinsicID() == Intrinsic::bswap) { 283 unsigned C = Operand->getType()->getPrimitiveSizeInBits() - 284 TI->getType()->getPrimitiveSizeInBits(); 285 Value *CV = ConstantInt::get(Operand->getType(), C); 286 Value *V = Builder->CreateLShr(Operand->getArgOperand(0), CV); 287 return new TruncInst(V, TI->getType()); 288 } 289 } 290 291 break; 292 case Intrinsic::powi: 293 if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 294 // powi(x, 0) -> 1.0 295 if (Power->isZero()) 296 return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0)); 297 // powi(x, 1) -> x 298 if (Power->isOne()) 299 return ReplaceInstUsesWith(CI, II->getArgOperand(0)); 300 // powi(x, -1) -> 1/x 301 if (Power->isAllOnesValue()) 302 return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0), 303 II->getArgOperand(0)); 304 } 305 break; 306 case Intrinsic::cttz: { 307 // If all bits below the first known one are known zero, 308 // this value is constant. 309 IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType()); 310 // FIXME: Try to simplify vectors of integers. 311 if (!IT) break; 312 uint32_t BitWidth = IT->getBitWidth(); 313 APInt KnownZero(BitWidth, 0); 314 APInt KnownOne(BitWidth, 0); 315 ComputeMaskedBits(II->getArgOperand(0), KnownZero, KnownOne); 316 unsigned TrailingZeros = KnownOne.countTrailingZeros(); 317 APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros)); 318 if ((Mask & KnownZero) == Mask) 319 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 320 APInt(BitWidth, TrailingZeros))); 321 322 } 323 break; 324 case Intrinsic::ctlz: { 325 // If all bits above the first known one are known zero, 326 // this value is constant. 327 IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType()); 328 // FIXME: Try to simplify vectors of integers. 329 if (!IT) break; 330 uint32_t BitWidth = IT->getBitWidth(); 331 APInt KnownZero(BitWidth, 0); 332 APInt KnownOne(BitWidth, 0); 333 ComputeMaskedBits(II->getArgOperand(0), KnownZero, KnownOne); 334 unsigned LeadingZeros = KnownOne.countLeadingZeros(); 335 APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros)); 336 if ((Mask & KnownZero) == Mask) 337 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 338 APInt(BitWidth, LeadingZeros))); 339 340 } 341 break; 342 case Intrinsic::uadd_with_overflow: { 343 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 344 IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 345 uint32_t BitWidth = IT->getBitWidth(); 346 APInt LHSKnownZero(BitWidth, 0); 347 APInt LHSKnownOne(BitWidth, 0); 348 ComputeMaskedBits(LHS, LHSKnownZero, LHSKnownOne); 349 bool LHSKnownNegative = LHSKnownOne[BitWidth - 1]; 350 bool LHSKnownPositive = LHSKnownZero[BitWidth - 1]; 351 352 if (LHSKnownNegative || LHSKnownPositive) { 353 APInt RHSKnownZero(BitWidth, 0); 354 APInt RHSKnownOne(BitWidth, 0); 355 ComputeMaskedBits(RHS, RHSKnownZero, RHSKnownOne); 356 bool RHSKnownNegative = RHSKnownOne[BitWidth - 1]; 357 bool RHSKnownPositive = RHSKnownZero[BitWidth - 1]; 358 if (LHSKnownNegative && RHSKnownNegative) { 359 // The sign bit is set in both cases: this MUST overflow. 360 // Create a simple add instruction, and insert it into the struct. 361 Value *Add = Builder->CreateAdd(LHS, RHS); 362 Add->takeName(&CI); 363 Constant *V[] = { 364 UndefValue::get(LHS->getType()), 365 ConstantInt::getTrue(II->getContext()) 366 }; 367 StructType *ST = cast<StructType>(II->getType()); 368 Constant *Struct = ConstantStruct::get(ST, V); 369 return InsertValueInst::Create(Struct, Add, 0); 370 } 371 372 if (LHSKnownPositive && RHSKnownPositive) { 373 // The sign bit is clear in both cases: this CANNOT overflow. 374 // Create a simple add instruction, and insert it into the struct. 375 Value *Add = Builder->CreateNUWAdd(LHS, RHS); 376 Add->takeName(&CI); 377 Constant *V[] = { 378 UndefValue::get(LHS->getType()), 379 ConstantInt::getFalse(II->getContext()) 380 }; 381 StructType *ST = cast<StructType>(II->getType()); 382 Constant *Struct = ConstantStruct::get(ST, V); 383 return InsertValueInst::Create(Struct, Add, 0); 384 } 385 } 386 } 387 // FALL THROUGH uadd into sadd 388 case Intrinsic::sadd_with_overflow: 389 // Canonicalize constants into the RHS. 390 if (isa<Constant>(II->getArgOperand(0)) && 391 !isa<Constant>(II->getArgOperand(1))) { 392 Value *LHS = II->getArgOperand(0); 393 II->setArgOperand(0, II->getArgOperand(1)); 394 II->setArgOperand(1, LHS); 395 return II; 396 } 397 398 // X + undef -> undef 399 if (isa<UndefValue>(II->getArgOperand(1))) 400 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 401 402 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 403 // X + 0 -> {X, false} 404 if (RHS->isZero()) { 405 Constant *V[] = { 406 UndefValue::get(II->getArgOperand(0)->getType()), 407 ConstantInt::getFalse(II->getContext()) 408 }; 409 Constant *Struct = 410 ConstantStruct::get(cast<StructType>(II->getType()), V); 411 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 412 } 413 } 414 break; 415 case Intrinsic::usub_with_overflow: 416 case Intrinsic::ssub_with_overflow: 417 // undef - X -> undef 418 // X - undef -> undef 419 if (isa<UndefValue>(II->getArgOperand(0)) || 420 isa<UndefValue>(II->getArgOperand(1))) 421 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 422 423 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 424 // X - 0 -> {X, false} 425 if (RHS->isZero()) { 426 Constant *V[] = { 427 UndefValue::get(II->getArgOperand(0)->getType()), 428 ConstantInt::getFalse(II->getContext()) 429 }; 430 Constant *Struct = 431 ConstantStruct::get(cast<StructType>(II->getType()), V); 432 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 433 } 434 } 435 break; 436 case Intrinsic::umul_with_overflow: { 437 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 438 unsigned BitWidth = cast<IntegerType>(LHS->getType())->getBitWidth(); 439 440 APInt LHSKnownZero(BitWidth, 0); 441 APInt LHSKnownOne(BitWidth, 0); 442 ComputeMaskedBits(LHS, LHSKnownZero, LHSKnownOne); 443 APInt RHSKnownZero(BitWidth, 0); 444 APInt RHSKnownOne(BitWidth, 0); 445 ComputeMaskedBits(RHS, RHSKnownZero, RHSKnownOne); 446 447 // Get the largest possible values for each operand. 448 APInt LHSMax = ~LHSKnownZero; 449 APInt RHSMax = ~RHSKnownZero; 450 451 // If multiplying the maximum values does not overflow then we can turn 452 // this into a plain NUW mul. 453 bool Overflow; 454 LHSMax.umul_ov(RHSMax, Overflow); 455 if (!Overflow) { 456 Value *Mul = Builder->CreateNUWMul(LHS, RHS, "umul_with_overflow"); 457 Constant *V[] = { 458 UndefValue::get(LHS->getType()), 459 Builder->getFalse() 460 }; 461 Constant *Struct = ConstantStruct::get(cast<StructType>(II->getType()),V); 462 return InsertValueInst::Create(Struct, Mul, 0); 463 } 464 } // FALL THROUGH 465 case Intrinsic::smul_with_overflow: 466 // Canonicalize constants into the RHS. 467 if (isa<Constant>(II->getArgOperand(0)) && 468 !isa<Constant>(II->getArgOperand(1))) { 469 Value *LHS = II->getArgOperand(0); 470 II->setArgOperand(0, II->getArgOperand(1)); 471 II->setArgOperand(1, LHS); 472 return II; 473 } 474 475 // X * undef -> undef 476 if (isa<UndefValue>(II->getArgOperand(1))) 477 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 478 479 if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 480 // X*0 -> {0, false} 481 if (RHSI->isZero()) 482 return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType())); 483 484 // X * 1 -> {X, false} 485 if (RHSI->equalsInt(1)) { 486 Constant *V[] = { 487 UndefValue::get(II->getArgOperand(0)->getType()), 488 ConstantInt::getFalse(II->getContext()) 489 }; 490 Constant *Struct = 491 ConstantStruct::get(cast<StructType>(II->getType()), V); 492 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 493 } 494 } 495 break; 496 case Intrinsic::ppc_altivec_lvx: 497 case Intrinsic::ppc_altivec_lvxl: 498 // Turn PPC lvx -> load if the pointer is known aligned. 499 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 500 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), 501 PointerType::getUnqual(II->getType())); 502 return new LoadInst(Ptr); 503 } 504 break; 505 case Intrinsic::ppc_altivec_stvx: 506 case Intrinsic::ppc_altivec_stvxl: 507 // Turn stvx -> store if the pointer is known aligned. 508 if (getOrEnforceKnownAlignment(II->getArgOperand(1), 16, TD) >= 16) { 509 Type *OpPtrTy = 510 PointerType::getUnqual(II->getArgOperand(0)->getType()); 511 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy); 512 return new StoreInst(II->getArgOperand(0), Ptr); 513 } 514 break; 515 case Intrinsic::x86_sse_storeu_ps: 516 case Intrinsic::x86_sse2_storeu_pd: 517 case Intrinsic::x86_sse2_storeu_dq: 518 // Turn X86 storeu -> store if the pointer is known aligned. 519 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 520 Type *OpPtrTy = 521 PointerType::getUnqual(II->getArgOperand(1)->getType()); 522 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy); 523 return new StoreInst(II->getArgOperand(1), Ptr); 524 } 525 break; 526 527 case Intrinsic::x86_sse_cvtss2si: 528 case Intrinsic::x86_sse_cvtss2si64: 529 case Intrinsic::x86_sse_cvttss2si: 530 case Intrinsic::x86_sse_cvttss2si64: 531 case Intrinsic::x86_sse2_cvtsd2si: 532 case Intrinsic::x86_sse2_cvtsd2si64: 533 case Intrinsic::x86_sse2_cvttsd2si: 534 case Intrinsic::x86_sse2_cvttsd2si64: { 535 // These intrinsics only demand the 0th element of their input vectors. If 536 // we can simplify the input based on that, do so now. 537 unsigned VWidth = 538 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 539 APInt DemandedElts(VWidth, 1); 540 APInt UndefElts(VWidth, 0); 541 if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0), 542 DemandedElts, UndefElts)) { 543 II->setArgOperand(0, V); 544 return II; 545 } 546 break; 547 } 548 549 550 case Intrinsic::x86_sse41_pmovsxbw: 551 case Intrinsic::x86_sse41_pmovsxwd: 552 case Intrinsic::x86_sse41_pmovsxdq: 553 case Intrinsic::x86_sse41_pmovzxbw: 554 case Intrinsic::x86_sse41_pmovzxwd: 555 case Intrinsic::x86_sse41_pmovzxdq: { 556 // pmov{s|z}x ignores the upper half of their input vectors. 557 unsigned VWidth = 558 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 559 unsigned LowHalfElts = VWidth / 2; 560 APInt InputDemandedElts(APInt::getBitsSet(VWidth, 0, LowHalfElts)); 561 APInt UndefElts(VWidth, 0); 562 if (Value *TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0), 563 InputDemandedElts, 564 UndefElts)) { 565 II->setArgOperand(0, TmpV); 566 return II; 567 } 568 break; 569 } 570 571 case Intrinsic::ppc_altivec_vperm: 572 // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant. 573 if (Constant *Mask = dyn_cast<Constant>(II->getArgOperand(2))) { 574 assert(Mask->getType()->getVectorNumElements() == 16 && 575 "Bad type for intrinsic!"); 576 577 // Check that all of the elements are integer constants or undefs. 578 bool AllEltsOk = true; 579 for (unsigned i = 0; i != 16; ++i) { 580 Constant *Elt = Mask->getAggregateElement(i); 581 if (Elt == 0 || 582 !(isa<ConstantInt>(Elt) || isa<UndefValue>(Elt))) { 583 AllEltsOk = false; 584 break; 585 } 586 } 587 588 if (AllEltsOk) { 589 // Cast the input vectors to byte vectors. 590 Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0), 591 Mask->getType()); 592 Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1), 593 Mask->getType()); 594 Value *Result = UndefValue::get(Op0->getType()); 595 596 // Only extract each element once. 597 Value *ExtractedElts[32]; 598 memset(ExtractedElts, 0, sizeof(ExtractedElts)); 599 600 for (unsigned i = 0; i != 16; ++i) { 601 if (isa<UndefValue>(Mask->getAggregateElement(i))) 602 continue; 603 unsigned Idx = 604 cast<ConstantInt>(Mask->getAggregateElement(i))->getZExtValue(); 605 Idx &= 31; // Match the hardware behavior. 606 607 if (ExtractedElts[Idx] == 0) { 608 ExtractedElts[Idx] = 609 Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1, 610 Builder->getInt32(Idx&15)); 611 } 612 613 // Insert this value into the result vector. 614 Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx], 615 Builder->getInt32(i)); 616 } 617 return CastInst::Create(Instruction::BitCast, Result, CI.getType()); 618 } 619 } 620 break; 621 622 case Intrinsic::arm_neon_vld1: 623 case Intrinsic::arm_neon_vld2: 624 case Intrinsic::arm_neon_vld3: 625 case Intrinsic::arm_neon_vld4: 626 case Intrinsic::arm_neon_vld2lane: 627 case Intrinsic::arm_neon_vld3lane: 628 case Intrinsic::arm_neon_vld4lane: 629 case Intrinsic::arm_neon_vst1: 630 case Intrinsic::arm_neon_vst2: 631 case Intrinsic::arm_neon_vst3: 632 case Intrinsic::arm_neon_vst4: 633 case Intrinsic::arm_neon_vst2lane: 634 case Intrinsic::arm_neon_vst3lane: 635 case Intrinsic::arm_neon_vst4lane: { 636 unsigned MemAlign = getKnownAlignment(II->getArgOperand(0), TD); 637 unsigned AlignArg = II->getNumArgOperands() - 1; 638 ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg)); 639 if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) { 640 II->setArgOperand(AlignArg, 641 ConstantInt::get(Type::getInt32Ty(II->getContext()), 642 MemAlign, false)); 643 return II; 644 } 645 break; 646 } 647 648 case Intrinsic::arm_neon_vmulls: 649 case Intrinsic::arm_neon_vmullu: { 650 Value *Arg0 = II->getArgOperand(0); 651 Value *Arg1 = II->getArgOperand(1); 652 653 // Handle mul by zero first: 654 if (isa<ConstantAggregateZero>(Arg0) || isa<ConstantAggregateZero>(Arg1)) { 655 return ReplaceInstUsesWith(CI, ConstantAggregateZero::get(II->getType())); 656 } 657 658 // Check for constant LHS & RHS - in this case we just simplify. 659 bool Zext = (II->getIntrinsicID() == Intrinsic::arm_neon_vmullu); 660 VectorType *NewVT = cast<VectorType>(II->getType()); 661 unsigned NewWidth = NewVT->getElementType()->getIntegerBitWidth(); 662 if (ConstantDataVector *CV0 = dyn_cast<ConstantDataVector>(Arg0)) { 663 if (ConstantDataVector *CV1 = dyn_cast<ConstantDataVector>(Arg1)) { 664 VectorType* VT = cast<VectorType>(CV0->getType()); 665 SmallVector<Constant*, 4> NewElems; 666 for (unsigned i = 0; i < VT->getNumElements(); ++i) { 667 APInt CV0E = 668 (cast<ConstantInt>(CV0->getAggregateElement(i)))->getValue(); 669 CV0E = Zext ? CV0E.zext(NewWidth) : CV0E.sext(NewWidth); 670 APInt CV1E = 671 (cast<ConstantInt>(CV1->getAggregateElement(i)))->getValue(); 672 CV1E = Zext ? CV1E.zext(NewWidth) : CV1E.sext(NewWidth); 673 NewElems.push_back( 674 ConstantInt::get(NewVT->getElementType(), CV0E * CV1E)); 675 } 676 return ReplaceInstUsesWith(CI, ConstantVector::get(NewElems)); 677 } 678 679 // Couldn't simplify - cannonicalize constant to the RHS. 680 std::swap(Arg0, Arg1); 681 } 682 683 // Handle mul by one: 684 if (ConstantDataVector *CV1 = dyn_cast<ConstantDataVector>(Arg1)) { 685 if (ConstantInt *Splat = 686 dyn_cast_or_null<ConstantInt>(CV1->getSplatValue())) { 687 if (Splat->isOne()) { 688 if (Zext) 689 return CastInst::CreateZExtOrBitCast(Arg0, II->getType()); 690 // else 691 return CastInst::CreateSExtOrBitCast(Arg0, II->getType()); 692 } 693 } 694 } 695 696 break; 697 } 698 699 case Intrinsic::stackrestore: { 700 // If the save is right next to the restore, remove the restore. This can 701 // happen when variable allocas are DCE'd. 702 if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 703 if (SS->getIntrinsicID() == Intrinsic::stacksave) { 704 BasicBlock::iterator BI = SS; 705 if (&*++BI == II) 706 return EraseInstFromFunction(CI); 707 } 708 } 709 710 // Scan down this block to see if there is another stack restore in the 711 // same block without an intervening call/alloca. 712 BasicBlock::iterator BI = II; 713 TerminatorInst *TI = II->getParent()->getTerminator(); 714 bool CannotRemove = false; 715 for (++BI; &*BI != TI; ++BI) { 716 if (isa<AllocaInst>(BI)) { 717 CannotRemove = true; 718 break; 719 } 720 if (CallInst *BCI = dyn_cast<CallInst>(BI)) { 721 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) { 722 // If there is a stackrestore below this one, remove this one. 723 if (II->getIntrinsicID() == Intrinsic::stackrestore) 724 return EraseInstFromFunction(CI); 725 // Otherwise, ignore the intrinsic. 726 } else { 727 // If we found a non-intrinsic call, we can't remove the stack 728 // restore. 729 CannotRemove = true; 730 break; 731 } 732 } 733 } 734 735 // If the stack restore is in a return, resume, or unwind block and if there 736 // are no allocas or calls between the restore and the return, nuke the 737 // restore. 738 if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI))) 739 return EraseInstFromFunction(CI); 740 break; 741 } 742 } 743 744 return visitCallSite(II); 745} 746 747// InvokeInst simplification 748// 749Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) { 750 return visitCallSite(&II); 751} 752 753/// isSafeToEliminateVarargsCast - If this cast does not affect the value 754/// passed through the varargs area, we can eliminate the use of the cast. 755static bool isSafeToEliminateVarargsCast(const CallSite CS, 756 const CastInst * const CI, 757 const DataLayout * const TD, 758 const int ix) { 759 if (!CI->isLosslessCast()) 760 return false; 761 762 // The size of ByVal arguments is derived from the type, so we 763 // can't change to a type with a different size. If the size were 764 // passed explicitly we could avoid this check. 765 if (!CS.isByValArgument(ix)) 766 return true; 767 768 Type* SrcTy = 769 cast<PointerType>(CI->getOperand(0)->getType())->getElementType(); 770 Type* DstTy = cast<PointerType>(CI->getType())->getElementType(); 771 if (!SrcTy->isSized() || !DstTy->isSized()) 772 return false; 773 if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy)) 774 return false; 775 return true; 776} 777 778namespace { 779class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls { 780 InstCombiner *IC; 781protected: 782 void replaceCall(Value *With) { 783 NewInstruction = IC->ReplaceInstUsesWith(*CI, With); 784 } 785 bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const { 786 if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp)) 787 return true; 788 if (ConstantInt *SizeCI = 789 dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) { 790 if (SizeCI->isAllOnesValue()) 791 return true; 792 if (isString) { 793 uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp)); 794 // If the length is 0 we don't know how long it is and so we can't 795 // remove the check. 796 if (Len == 0) return false; 797 return SizeCI->getZExtValue() >= Len; 798 } 799 if (ConstantInt *Arg = dyn_cast<ConstantInt>( 800 CI->getArgOperand(SizeArgOp))) 801 return SizeCI->getZExtValue() >= Arg->getZExtValue(); 802 } 803 return false; 804 } 805public: 806 InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { } 807 Instruction *NewInstruction; 808}; 809} // end anonymous namespace 810 811// Try to fold some different type of calls here. 812// Currently we're only working with the checking functions, memcpy_chk, 813// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk, 814// strcat_chk and strncat_chk. 815Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const DataLayout *TD) { 816 if (CI->getCalledFunction() == 0) return 0; 817 818 InstCombineFortifiedLibCalls Simplifier(this); 819 Simplifier.fold(CI, TD, TLI); 820 return Simplifier.NewInstruction; 821} 822 823static IntrinsicInst *FindInitTrampolineFromAlloca(Value *TrampMem) { 824 // Strip off at most one level of pointer casts, looking for an alloca. This 825 // is good enough in practice and simpler than handling any number of casts. 826 Value *Underlying = TrampMem->stripPointerCasts(); 827 if (Underlying != TrampMem && 828 (!Underlying->hasOneUse() || *Underlying->use_begin() != TrampMem)) 829 return 0; 830 if (!isa<AllocaInst>(Underlying)) 831 return 0; 832 833 IntrinsicInst *InitTrampoline = 0; 834 for (Value::use_iterator I = TrampMem->use_begin(), E = TrampMem->use_end(); 835 I != E; I++) { 836 IntrinsicInst *II = dyn_cast<IntrinsicInst>(*I); 837 if (!II) 838 return 0; 839 if (II->getIntrinsicID() == Intrinsic::init_trampoline) { 840 if (InitTrampoline) 841 // More than one init_trampoline writes to this value. Give up. 842 return 0; 843 InitTrampoline = II; 844 continue; 845 } 846 if (II->getIntrinsicID() == Intrinsic::adjust_trampoline) 847 // Allow any number of calls to adjust.trampoline. 848 continue; 849 return 0; 850 } 851 852 // No call to init.trampoline found. 853 if (!InitTrampoline) 854 return 0; 855 856 // Check that the alloca is being used in the expected way. 857 if (InitTrampoline->getOperand(0) != TrampMem) 858 return 0; 859 860 return InitTrampoline; 861} 862 863static IntrinsicInst *FindInitTrampolineFromBB(IntrinsicInst *AdjustTramp, 864 Value *TrampMem) { 865 // Visit all the previous instructions in the basic block, and try to find a 866 // init.trampoline which has a direct path to the adjust.trampoline. 867 for (BasicBlock::iterator I = AdjustTramp, 868 E = AdjustTramp->getParent()->begin(); I != E; ) { 869 Instruction *Inst = --I; 870 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) 871 if (II->getIntrinsicID() == Intrinsic::init_trampoline && 872 II->getOperand(0) == TrampMem) 873 return II; 874 if (Inst->mayWriteToMemory()) 875 return 0; 876 } 877 return 0; 878} 879 880// Given a call to llvm.adjust.trampoline, find and return the corresponding 881// call to llvm.init.trampoline if the call to the trampoline can be optimized 882// to a direct call to a function. Otherwise return NULL. 883// 884static IntrinsicInst *FindInitTrampoline(Value *Callee) { 885 Callee = Callee->stripPointerCasts(); 886 IntrinsicInst *AdjustTramp = dyn_cast<IntrinsicInst>(Callee); 887 if (!AdjustTramp || 888 AdjustTramp->getIntrinsicID() != Intrinsic::adjust_trampoline) 889 return 0; 890 891 Value *TrampMem = AdjustTramp->getOperand(0); 892 893 if (IntrinsicInst *IT = FindInitTrampolineFromAlloca(TrampMem)) 894 return IT; 895 if (IntrinsicInst *IT = FindInitTrampolineFromBB(AdjustTramp, TrampMem)) 896 return IT; 897 return 0; 898} 899 900// visitCallSite - Improvements for call and invoke instructions. 901// 902Instruction *InstCombiner::visitCallSite(CallSite CS) { 903 if (isAllocLikeFn(CS.getInstruction(), TLI)) 904 return visitAllocSite(*CS.getInstruction()); 905 906 bool Changed = false; 907 908 // If the callee is a pointer to a function, attempt to move any casts to the 909 // arguments of the call/invoke. 910 Value *Callee = CS.getCalledValue(); 911 if (!isa<Function>(Callee) && transformConstExprCastCall(CS)) 912 return 0; 913 914 if (Function *CalleeF = dyn_cast<Function>(Callee)) 915 // If the call and callee calling conventions don't match, this call must 916 // be unreachable, as the call is undefined. 917 if (CalleeF->getCallingConv() != CS.getCallingConv() && 918 // Only do this for calls to a function with a body. A prototype may 919 // not actually end up matching the implementation's calling conv for a 920 // variety of reasons (e.g. it may be written in assembly). 921 !CalleeF->isDeclaration()) { 922 Instruction *OldCall = CS.getInstruction(); 923 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 924 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 925 OldCall); 926 // If OldCall dues not return void then replaceAllUsesWith undef. 927 // This allows ValueHandlers and custom metadata to adjust itself. 928 if (!OldCall->getType()->isVoidTy()) 929 ReplaceInstUsesWith(*OldCall, UndefValue::get(OldCall->getType())); 930 if (isa<CallInst>(OldCall)) 931 return EraseInstFromFunction(*OldCall); 932 933 // We cannot remove an invoke, because it would change the CFG, just 934 // change the callee to a null pointer. 935 cast<InvokeInst>(OldCall)->setCalledFunction( 936 Constant::getNullValue(CalleeF->getType())); 937 return 0; 938 } 939 940 if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) { 941 // If CS does not return void then replaceAllUsesWith undef. 942 // This allows ValueHandlers and custom metadata to adjust itself. 943 if (!CS.getInstruction()->getType()->isVoidTy()) 944 ReplaceInstUsesWith(*CS.getInstruction(), 945 UndefValue::get(CS.getInstruction()->getType())); 946 947 if (isa<InvokeInst>(CS.getInstruction())) { 948 // Can't remove an invoke because we cannot change the CFG. 949 return 0; 950 } 951 952 // This instruction is not reachable, just remove it. We insert a store to 953 // undef so that we know that this code is not reachable, despite the fact 954 // that we can't modify the CFG here. 955 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 956 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 957 CS.getInstruction()); 958 959 return EraseInstFromFunction(*CS.getInstruction()); 960 } 961 962 if (IntrinsicInst *II = FindInitTrampoline(Callee)) 963 return transformCallThroughTrampoline(CS, II); 964 965 PointerType *PTy = cast<PointerType>(Callee->getType()); 966 FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 967 if (FTy->isVarArg()) { 968 int ix = FTy->getNumParams(); 969 // See if we can optimize any arguments passed through the varargs area of 970 // the call. 971 for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(), 972 E = CS.arg_end(); I != E; ++I, ++ix) { 973 CastInst *CI = dyn_cast<CastInst>(*I); 974 if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) { 975 *I = CI->getOperand(0); 976 Changed = true; 977 } 978 } 979 } 980 981 if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) { 982 // Inline asm calls cannot throw - mark them 'nounwind'. 983 CS.setDoesNotThrow(); 984 Changed = true; 985 } 986 987 // Try to optimize the call if possible, we require DataLayout for most of 988 // this. None of these calls are seen as possibly dead so go ahead and 989 // delete the instruction now. 990 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) { 991 Instruction *I = tryOptimizeCall(CI, TD); 992 // If we changed something return the result, etc. Otherwise let 993 // the fallthrough check. 994 if (I) return EraseInstFromFunction(*I); 995 } 996 997 return Changed ? CS.getInstruction() : 0; 998} 999 1000// transformConstExprCastCall - If the callee is a constexpr cast of a function, 1001// attempt to move the cast to the arguments of the call/invoke. 1002// 1003bool InstCombiner::transformConstExprCastCall(CallSite CS) { 1004 Function *Callee = 1005 dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); 1006 if (Callee == 0) 1007 return false; 1008 Instruction *Caller = CS.getInstruction(); 1009 const AttrListPtr &CallerPAL = CS.getAttributes(); 1010 1011 // Okay, this is a cast from a function to a different type. Unless doing so 1012 // would cause a type conversion of one of our arguments, change this call to 1013 // be a direct call with arguments casted to the appropriate types. 1014 // 1015 FunctionType *FT = Callee->getFunctionType(); 1016 Type *OldRetTy = Caller->getType(); 1017 Type *NewRetTy = FT->getReturnType(); 1018 1019 if (NewRetTy->isStructTy()) 1020 return false; // TODO: Handle multiple return values. 1021 1022 // Check to see if we are changing the return type... 1023 if (OldRetTy != NewRetTy) { 1024 if (Callee->isDeclaration() && 1025 // Conversion is ok if changing from one pointer type to another or from 1026 // a pointer to an integer of the same size. 1027 !((OldRetTy->isPointerTy() || !TD || 1028 OldRetTy == TD->getIntPtrType(Caller->getContext())) && 1029 (NewRetTy->isPointerTy() || !TD || 1030 NewRetTy == TD->getIntPtrType(Caller->getContext())))) 1031 return false; // Cannot transform this return value. 1032 1033 if (!Caller->use_empty() && 1034 // void -> non-void is handled specially 1035 !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy)) 1036 return false; // Cannot transform this return value. 1037 1038 if (!CallerPAL.isEmpty() && !Caller->use_empty()) { 1039 Attributes::Builder RAttrs = CallerPAL.getRetAttributes(); 1040 if (RAttrs.hasAttributes(Attributes::typeIncompatible(NewRetTy))) 1041 return false; // Attribute not compatible with transformed value. 1042 } 1043 1044 // If the callsite is an invoke instruction, and the return value is used by 1045 // a PHI node in a successor, we cannot change the return type of the call 1046 // because there is no place to put the cast instruction (without breaking 1047 // the critical edge). Bail out in this case. 1048 if (!Caller->use_empty()) 1049 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) 1050 for (Value::use_iterator UI = II->use_begin(), E = II->use_end(); 1051 UI != E; ++UI) 1052 if (PHINode *PN = dyn_cast<PHINode>(*UI)) 1053 if (PN->getParent() == II->getNormalDest() || 1054 PN->getParent() == II->getUnwindDest()) 1055 return false; 1056 } 1057 1058 unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin()); 1059 unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); 1060 1061 CallSite::arg_iterator AI = CS.arg_begin(); 1062 for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { 1063 Type *ParamTy = FT->getParamType(i); 1064 Type *ActTy = (*AI)->getType(); 1065 1066 if (!CastInst::isCastable(ActTy, ParamTy)) 1067 return false; // Cannot transform this parameter value. 1068 1069 Attributes Attrs = CallerPAL.getParamAttributes(i + 1); 1070 if (Attrs & Attributes::typeIncompatible(ParamTy)) 1071 return false; // Attribute not compatible with transformed value. 1072 1073 // If the parameter is passed as a byval argument, then we have to have a 1074 // sized type and the sized type has to have the same size as the old type. 1075 if (ParamTy != ActTy && Attrs.hasAttribute(Attributes::ByVal)) { 1076 PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy); 1077 if (ParamPTy == 0 || !ParamPTy->getElementType()->isSized() || TD == 0) 1078 return false; 1079 1080 Type *CurElTy = cast<PointerType>(ActTy)->getElementType(); 1081 if (TD->getTypeAllocSize(CurElTy) != 1082 TD->getTypeAllocSize(ParamPTy->getElementType())) 1083 return false; 1084 } 1085 1086 // Converting from one pointer type to another or between a pointer and an 1087 // integer of the same size is safe even if we do not have a body. 1088 bool isConvertible = ActTy == ParamTy || 1089 (TD && ((ParamTy->isPointerTy() || 1090 ParamTy == TD->getIntPtrType(Caller->getContext())) && 1091 (ActTy->isPointerTy() || 1092 ActTy == TD->getIntPtrType(Caller->getContext())))); 1093 if (Callee->isDeclaration() && !isConvertible) return false; 1094 } 1095 1096 if (Callee->isDeclaration()) { 1097 // Do not delete arguments unless we have a function body. 1098 if (FT->getNumParams() < NumActualArgs && !FT->isVarArg()) 1099 return false; 1100 1101 // If the callee is just a declaration, don't change the varargsness of the 1102 // call. We don't want to introduce a varargs call where one doesn't 1103 // already exist. 1104 PointerType *APTy = cast<PointerType>(CS.getCalledValue()->getType()); 1105 if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg()) 1106 return false; 1107 1108 // If both the callee and the cast type are varargs, we still have to make 1109 // sure the number of fixed parameters are the same or we have the same 1110 // ABI issues as if we introduce a varargs call. 1111 if (FT->isVarArg() && 1112 cast<FunctionType>(APTy->getElementType())->isVarArg() && 1113 FT->getNumParams() != 1114 cast<FunctionType>(APTy->getElementType())->getNumParams()) 1115 return false; 1116 } 1117 1118 if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && 1119 !CallerPAL.isEmpty()) 1120 // In this case we have more arguments than the new function type, but we 1121 // won't be dropping them. Check that these extra arguments have attributes 1122 // that are compatible with being a vararg call argument. 1123 for (unsigned i = CallerPAL.getNumSlots(); i; --i) { 1124 if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams()) 1125 break; 1126 Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs; 1127 if (PAttrs.hasIncompatibleWithVarArgsAttrs()) 1128 return false; 1129 } 1130 1131 1132 // Okay, we decided that this is a safe thing to do: go ahead and start 1133 // inserting cast instructions as necessary. 1134 std::vector<Value*> Args; 1135 Args.reserve(NumActualArgs); 1136 SmallVector<AttributeWithIndex, 8> attrVec; 1137 attrVec.reserve(NumCommonArgs); 1138 1139 // Get any return attributes. 1140 Attributes::Builder RAttrs = CallerPAL.getRetAttributes(); 1141 1142 // If the return value is not being used, the type may not be compatible 1143 // with the existing attributes. Wipe out any problematic attributes. 1144 RAttrs.removeAttributes(Attributes::typeIncompatible(NewRetTy)); 1145 1146 // Add the new return attributes. 1147 if (RAttrs.hasAttributes()) 1148 attrVec.push_back(AttributeWithIndex::get(0, Attributes::get(RAttrs))); 1149 1150 AI = CS.arg_begin(); 1151 for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { 1152 Type *ParamTy = FT->getParamType(i); 1153 if ((*AI)->getType() == ParamTy) { 1154 Args.push_back(*AI); 1155 } else { 1156 Instruction::CastOps opcode = CastInst::getCastOpcode(*AI, 1157 false, ParamTy, false); 1158 Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy)); 1159 } 1160 1161 // Add any parameter attributes. 1162 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1163 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1164 } 1165 1166 // If the function takes more arguments than the call was taking, add them 1167 // now. 1168 for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) 1169 Args.push_back(Constant::getNullValue(FT->getParamType(i))); 1170 1171 // If we are removing arguments to the function, emit an obnoxious warning. 1172 if (FT->getNumParams() < NumActualArgs) { 1173 if (!FT->isVarArg()) { 1174 errs() << "WARNING: While resolving call to function '" 1175 << Callee->getName() << "' arguments were dropped!\n"; 1176 } else { 1177 // Add all of the arguments in their promoted form to the arg list. 1178 for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { 1179 Type *PTy = getPromotedType((*AI)->getType()); 1180 if (PTy != (*AI)->getType()) { 1181 // Must promote to pass through va_arg area! 1182 Instruction::CastOps opcode = 1183 CastInst::getCastOpcode(*AI, false, PTy, false); 1184 Args.push_back(Builder->CreateCast(opcode, *AI, PTy)); 1185 } else { 1186 Args.push_back(*AI); 1187 } 1188 1189 // Add any parameter attributes. 1190 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1191 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1192 } 1193 } 1194 } 1195 1196 if (Attributes FnAttrs = CallerPAL.getFnAttributes()) 1197 attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs)); 1198 1199 if (NewRetTy->isVoidTy()) 1200 Caller->setName(""); // Void type should not have a name. 1201 1202 const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec); 1203 1204 Instruction *NC; 1205 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1206 NC = Builder->CreateInvoke(Callee, II->getNormalDest(), 1207 II->getUnwindDest(), Args); 1208 NC->takeName(II); 1209 cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv()); 1210 cast<InvokeInst>(NC)->setAttributes(NewCallerPAL); 1211 } else { 1212 CallInst *CI = cast<CallInst>(Caller); 1213 NC = Builder->CreateCall(Callee, Args); 1214 NC->takeName(CI); 1215 if (CI->isTailCall()) 1216 cast<CallInst>(NC)->setTailCall(); 1217 cast<CallInst>(NC)->setCallingConv(CI->getCallingConv()); 1218 cast<CallInst>(NC)->setAttributes(NewCallerPAL); 1219 } 1220 1221 // Insert a cast of the return type as necessary. 1222 Value *NV = NC; 1223 if (OldRetTy != NV->getType() && !Caller->use_empty()) { 1224 if (!NV->getType()->isVoidTy()) { 1225 Instruction::CastOps opcode = 1226 CastInst::getCastOpcode(NC, false, OldRetTy, false); 1227 NV = NC = CastInst::Create(opcode, NC, OldRetTy); 1228 NC->setDebugLoc(Caller->getDebugLoc()); 1229 1230 // If this is an invoke instruction, we should insert it after the first 1231 // non-phi, instruction in the normal successor block. 1232 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1233 BasicBlock::iterator I = II->getNormalDest()->getFirstInsertionPt(); 1234 InsertNewInstBefore(NC, *I); 1235 } else { 1236 // Otherwise, it's a call, just insert cast right after the call. 1237 InsertNewInstBefore(NC, *Caller); 1238 } 1239 Worklist.AddUsersToWorkList(*Caller); 1240 } else { 1241 NV = UndefValue::get(Caller->getType()); 1242 } 1243 } 1244 1245 if (!Caller->use_empty()) 1246 ReplaceInstUsesWith(*Caller, NV); 1247 1248 EraseInstFromFunction(*Caller); 1249 return true; 1250} 1251 1252// transformCallThroughTrampoline - Turn a call to a function created by 1253// init_trampoline / adjust_trampoline intrinsic pair into a direct call to the 1254// underlying function. 1255// 1256Instruction * 1257InstCombiner::transformCallThroughTrampoline(CallSite CS, 1258 IntrinsicInst *Tramp) { 1259 Value *Callee = CS.getCalledValue(); 1260 PointerType *PTy = cast<PointerType>(Callee->getType()); 1261 FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 1262 const AttrListPtr &Attrs = CS.getAttributes(); 1263 1264 // If the call already has the 'nest' attribute somewhere then give up - 1265 // otherwise 'nest' would occur twice after splicing in the chain. 1266 for (unsigned I = 0, E = Attrs.getNumAttrs(); I != E; ++I) 1267 if (Attrs.getAttributesAtIndex(I).hasAttribute(Attributes::Nest)) 1268 return 0; 1269 1270 assert(Tramp && 1271 "transformCallThroughTrampoline called with incorrect CallSite."); 1272 1273 Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts()); 1274 PointerType *NestFPTy = cast<PointerType>(NestF->getType()); 1275 FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType()); 1276 1277 const AttrListPtr &NestAttrs = NestF->getAttributes(); 1278 if (!NestAttrs.isEmpty()) { 1279 unsigned NestIdx = 1; 1280 Type *NestTy = 0; 1281 Attributes NestAttr; 1282 1283 // Look for a parameter marked with the 'nest' attribute. 1284 for (FunctionType::param_iterator I = NestFTy->param_begin(), 1285 E = NestFTy->param_end(); I != E; ++NestIdx, ++I) 1286 if (NestAttrs.getParamAttributes(NestIdx).hasAttribute(Attributes::Nest)){ 1287 // Record the parameter type and any other attributes. 1288 NestTy = *I; 1289 NestAttr = NestAttrs.getParamAttributes(NestIdx); 1290 break; 1291 } 1292 1293 if (NestTy) { 1294 Instruction *Caller = CS.getInstruction(); 1295 std::vector<Value*> NewArgs; 1296 NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1); 1297 1298 SmallVector<AttributeWithIndex, 8> NewAttrs; 1299 NewAttrs.reserve(Attrs.getNumSlots() + 1); 1300 1301 // Insert the nest argument into the call argument list, which may 1302 // mean appending it. Likewise for attributes. 1303 1304 // Add any result attributes. 1305 if (Attributes Attr = Attrs.getRetAttributes()) 1306 NewAttrs.push_back(AttributeWithIndex::get(0, Attr)); 1307 1308 { 1309 unsigned Idx = 1; 1310 CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); 1311 do { 1312 if (Idx == NestIdx) { 1313 // Add the chain argument and attributes. 1314 Value *NestVal = Tramp->getArgOperand(2); 1315 if (NestVal->getType() != NestTy) 1316 NestVal = Builder->CreateBitCast(NestVal, NestTy, "nest"); 1317 NewArgs.push_back(NestVal); 1318 NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr)); 1319 } 1320 1321 if (I == E) 1322 break; 1323 1324 // Add the original argument and attributes. 1325 NewArgs.push_back(*I); 1326 if (Attributes Attr = Attrs.getParamAttributes(Idx)) 1327 NewAttrs.push_back 1328 (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr)); 1329 1330 ++Idx, ++I; 1331 } while (1); 1332 } 1333 1334 // Add any function attributes. 1335 if (Attributes Attr = Attrs.getFnAttributes()) 1336 NewAttrs.push_back(AttributeWithIndex::get(~0, Attr)); 1337 1338 // The trampoline may have been bitcast to a bogus type (FTy). 1339 // Handle this by synthesizing a new function type, equal to FTy 1340 // with the chain parameter inserted. 1341 1342 std::vector<Type*> NewTypes; 1343 NewTypes.reserve(FTy->getNumParams()+1); 1344 1345 // Insert the chain's type into the list of parameter types, which may 1346 // mean appending it. 1347 { 1348 unsigned Idx = 1; 1349 FunctionType::param_iterator I = FTy->param_begin(), 1350 E = FTy->param_end(); 1351 1352 do { 1353 if (Idx == NestIdx) 1354 // Add the chain's type. 1355 NewTypes.push_back(NestTy); 1356 1357 if (I == E) 1358 break; 1359 1360 // Add the original type. 1361 NewTypes.push_back(*I); 1362 1363 ++Idx, ++I; 1364 } while (1); 1365 } 1366 1367 // Replace the trampoline call with a direct call. Let the generic 1368 // code sort out any function type mismatches. 1369 FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, 1370 FTy->isVarArg()); 1371 Constant *NewCallee = 1372 NestF->getType() == PointerType::getUnqual(NewFTy) ? 1373 NestF : ConstantExpr::getBitCast(NestF, 1374 PointerType::getUnqual(NewFTy)); 1375 const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs); 1376 1377 Instruction *NewCaller; 1378 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1379 NewCaller = InvokeInst::Create(NewCallee, 1380 II->getNormalDest(), II->getUnwindDest(), 1381 NewArgs); 1382 cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv()); 1383 cast<InvokeInst>(NewCaller)->setAttributes(NewPAL); 1384 } else { 1385 NewCaller = CallInst::Create(NewCallee, NewArgs); 1386 if (cast<CallInst>(Caller)->isTailCall()) 1387 cast<CallInst>(NewCaller)->setTailCall(); 1388 cast<CallInst>(NewCaller)-> 1389 setCallingConv(cast<CallInst>(Caller)->getCallingConv()); 1390 cast<CallInst>(NewCaller)->setAttributes(NewPAL); 1391 } 1392 1393 return NewCaller; 1394 } 1395 } 1396 1397 // Replace the trampoline call with a direct call. Since there is no 'nest' 1398 // parameter, there is no need to adjust the argument list. Let the generic 1399 // code sort out any function type mismatches. 1400 Constant *NewCallee = 1401 NestF->getType() == PTy ? NestF : 1402 ConstantExpr::getBitCast(NestF, PTy); 1403 CS.setCalledFunction(NewCallee); 1404 return CS.getInstruction(); 1405} 1406