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