1 //===- InstCombineCalls.cpp -----------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the visitCall, visitInvoke, and visitCallBr functions. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "InstCombineInternal.h" 14 #include "llvm/ADT/APFloat.h" 15 #include "llvm/ADT/APInt.h" 16 #include "llvm/ADT/APSInt.h" 17 #include "llvm/ADT/ArrayRef.h" 18 #include "llvm/ADT/STLFunctionalExtras.h" 19 #include "llvm/ADT/SmallBitVector.h" 20 #include "llvm/ADT/SmallVector.h" 21 #include "llvm/ADT/Statistic.h" 22 #include "llvm/Analysis/AliasAnalysis.h" 23 #include "llvm/Analysis/AssumeBundleQueries.h" 24 #include "llvm/Analysis/AssumptionCache.h" 25 #include "llvm/Analysis/InstructionSimplify.h" 26 #include "llvm/Analysis/Loads.h" 27 #include "llvm/Analysis/MemoryBuiltins.h" 28 #include "llvm/Analysis/ValueTracking.h" 29 #include "llvm/Analysis/VectorUtils.h" 30 #include "llvm/IR/AttributeMask.h" 31 #include "llvm/IR/Attributes.h" 32 #include "llvm/IR/BasicBlock.h" 33 #include "llvm/IR/Constant.h" 34 #include "llvm/IR/Constants.h" 35 #include "llvm/IR/DataLayout.h" 36 #include "llvm/IR/DebugInfo.h" 37 #include "llvm/IR/DerivedTypes.h" 38 #include "llvm/IR/Function.h" 39 #include "llvm/IR/GlobalVariable.h" 40 #include "llvm/IR/InlineAsm.h" 41 #include "llvm/IR/InstrTypes.h" 42 #include "llvm/IR/Instruction.h" 43 #include "llvm/IR/Instructions.h" 44 #include "llvm/IR/IntrinsicInst.h" 45 #include "llvm/IR/Intrinsics.h" 46 #include "llvm/IR/IntrinsicsAArch64.h" 47 #include "llvm/IR/IntrinsicsAMDGPU.h" 48 #include "llvm/IR/IntrinsicsARM.h" 49 #include "llvm/IR/IntrinsicsHexagon.h" 50 #include "llvm/IR/LLVMContext.h" 51 #include "llvm/IR/Metadata.h" 52 #include "llvm/IR/PatternMatch.h" 53 #include "llvm/IR/Statepoint.h" 54 #include "llvm/IR/Type.h" 55 #include "llvm/IR/User.h" 56 #include "llvm/IR/Value.h" 57 #include "llvm/IR/ValueHandle.h" 58 #include "llvm/Support/AtomicOrdering.h" 59 #include "llvm/Support/Casting.h" 60 #include "llvm/Support/CommandLine.h" 61 #include "llvm/Support/Compiler.h" 62 #include "llvm/Support/Debug.h" 63 #include "llvm/Support/ErrorHandling.h" 64 #include "llvm/Support/KnownBits.h" 65 #include "llvm/Support/MathExtras.h" 66 #include "llvm/Support/raw_ostream.h" 67 #include "llvm/Transforms/InstCombine/InstCombiner.h" 68 #include "llvm/Transforms/Utils/AssumeBundleBuilder.h" 69 #include "llvm/Transforms/Utils/Local.h" 70 #include "llvm/Transforms/Utils/SimplifyLibCalls.h" 71 #include <algorithm> 72 #include <cassert> 73 #include <cstdint> 74 #include <optional> 75 #include <utility> 76 #include <vector> 77 78 #define DEBUG_TYPE "instcombine" 79 #include "llvm/Transforms/Utils/InstructionWorklist.h" 80 81 using namespace llvm; 82 using namespace PatternMatch; 83 84 STATISTIC(NumSimplified, "Number of library calls simplified"); 85 86 static cl::opt<unsigned> GuardWideningWindow( 87 "instcombine-guard-widening-window", 88 cl::init(3), 89 cl::desc("How wide an instruction window to bypass looking for " 90 "another guard")); 91 92 /// Return the specified type promoted as it would be to pass though a va_arg 93 /// area. 94 static Type *getPromotedType(Type *Ty) { 95 if (IntegerType* ITy = dyn_cast<IntegerType>(Ty)) { 96 if (ITy->getBitWidth() < 32) 97 return Type::getInt32Ty(Ty->getContext()); 98 } 99 return Ty; 100 } 101 102 /// Recognize a memcpy/memmove from a trivially otherwise unused alloca. 103 /// TODO: This should probably be integrated with visitAllocSites, but that 104 /// requires a deeper change to allow either unread or unwritten objects. 105 static bool hasUndefSource(AnyMemTransferInst *MI) { 106 auto *Src = MI->getRawSource(); 107 while (isa<GetElementPtrInst>(Src) || isa<BitCastInst>(Src)) { 108 if (!Src->hasOneUse()) 109 return false; 110 Src = cast<Instruction>(Src)->getOperand(0); 111 } 112 return isa<AllocaInst>(Src) && Src->hasOneUse(); 113 } 114 115 Instruction *InstCombinerImpl::SimplifyAnyMemTransfer(AnyMemTransferInst *MI) { 116 Align DstAlign = getKnownAlignment(MI->getRawDest(), DL, MI, &AC, &DT); 117 MaybeAlign CopyDstAlign = MI->getDestAlign(); 118 if (!CopyDstAlign || *CopyDstAlign < DstAlign) { 119 MI->setDestAlignment(DstAlign); 120 return MI; 121 } 122 123 Align SrcAlign = getKnownAlignment(MI->getRawSource(), DL, MI, &AC, &DT); 124 MaybeAlign CopySrcAlign = MI->getSourceAlign(); 125 if (!CopySrcAlign || *CopySrcAlign < SrcAlign) { 126 MI->setSourceAlignment(SrcAlign); 127 return MI; 128 } 129 130 // If we have a store to a location which is known constant, we can conclude 131 // that the store must be storing the constant value (else the memory 132 // wouldn't be constant), and this must be a noop. 133 if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) { 134 // Set the size of the copy to 0, it will be deleted on the next iteration. 135 MI->setLength(Constant::getNullValue(MI->getLength()->getType())); 136 return MI; 137 } 138 139 // If the source is provably undef, the memcpy/memmove doesn't do anything 140 // (unless the transfer is volatile). 141 if (hasUndefSource(MI) && !MI->isVolatile()) { 142 // Set the size of the copy to 0, it will be deleted on the next iteration. 143 MI->setLength(Constant::getNullValue(MI->getLength()->getType())); 144 return MI; 145 } 146 147 // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with 148 // load/store. 149 ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getLength()); 150 if (!MemOpLength) return nullptr; 151 152 // Source and destination pointer types are always "i8*" for intrinsic. See 153 // if the size is something we can handle with a single primitive load/store. 154 // A single load+store correctly handles overlapping memory in the memmove 155 // case. 156 uint64_t Size = MemOpLength->getLimitedValue(); 157 assert(Size && "0-sized memory transferring should be removed already."); 158 159 if (Size > 8 || (Size&(Size-1))) 160 return nullptr; // If not 1/2/4/8 bytes, exit. 161 162 // If it is an atomic and alignment is less than the size then we will 163 // introduce the unaligned memory access which will be later transformed 164 // into libcall in CodeGen. This is not evident performance gain so disable 165 // it now. 166 if (isa<AtomicMemTransferInst>(MI)) 167 if (*CopyDstAlign < Size || *CopySrcAlign < Size) 168 return nullptr; 169 170 // Use an integer load+store unless we can find something better. 171 IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3); 172 173 // If the memcpy has metadata describing the members, see if we can get the 174 // TBAA, scope and noalias tags describing our copy. 175 AAMDNodes AACopyMD = MI->getAAMetadata().adjustForAccess(Size); 176 177 Value *Src = MI->getArgOperand(1); 178 Value *Dest = MI->getArgOperand(0); 179 LoadInst *L = Builder.CreateLoad(IntType, Src); 180 // Alignment from the mem intrinsic will be better, so use it. 181 L->setAlignment(*CopySrcAlign); 182 L->setAAMetadata(AACopyMD); 183 MDNode *LoopMemParallelMD = 184 MI->getMetadata(LLVMContext::MD_mem_parallel_loop_access); 185 if (LoopMemParallelMD) 186 L->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD); 187 MDNode *AccessGroupMD = MI->getMetadata(LLVMContext::MD_access_group); 188 if (AccessGroupMD) 189 L->setMetadata(LLVMContext::MD_access_group, AccessGroupMD); 190 191 StoreInst *S = Builder.CreateStore(L, Dest); 192 // Alignment from the mem intrinsic will be better, so use it. 193 S->setAlignment(*CopyDstAlign); 194 S->setAAMetadata(AACopyMD); 195 if (LoopMemParallelMD) 196 S->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD); 197 if (AccessGroupMD) 198 S->setMetadata(LLVMContext::MD_access_group, AccessGroupMD); 199 S->copyMetadata(*MI, LLVMContext::MD_DIAssignID); 200 201 if (auto *MT = dyn_cast<MemTransferInst>(MI)) { 202 // non-atomics can be volatile 203 L->setVolatile(MT->isVolatile()); 204 S->setVolatile(MT->isVolatile()); 205 } 206 if (isa<AtomicMemTransferInst>(MI)) { 207 // atomics have to be unordered 208 L->setOrdering(AtomicOrdering::Unordered); 209 S->setOrdering(AtomicOrdering::Unordered); 210 } 211 212 // Set the size of the copy to 0, it will be deleted on the next iteration. 213 MI->setLength(Constant::getNullValue(MemOpLength->getType())); 214 return MI; 215 } 216 217 Instruction *InstCombinerImpl::SimplifyAnyMemSet(AnyMemSetInst *MI) { 218 const Align KnownAlignment = 219 getKnownAlignment(MI->getDest(), DL, MI, &AC, &DT); 220 MaybeAlign MemSetAlign = MI->getDestAlign(); 221 if (!MemSetAlign || *MemSetAlign < KnownAlignment) { 222 MI->setDestAlignment(KnownAlignment); 223 return MI; 224 } 225 226 // If we have a store to a location which is known constant, we can conclude 227 // that the store must be storing the constant value (else the memory 228 // wouldn't be constant), and this must be a noop. 229 if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) { 230 // Set the size of the copy to 0, it will be deleted on the next iteration. 231 MI->setLength(Constant::getNullValue(MI->getLength()->getType())); 232 return MI; 233 } 234 235 // Remove memset with an undef value. 236 // FIXME: This is technically incorrect because it might overwrite a poison 237 // value. Change to PoisonValue once #52930 is resolved. 238 if (isa<UndefValue>(MI->getValue())) { 239 // Set the size of the copy to 0, it will be deleted on the next iteration. 240 MI->setLength(Constant::getNullValue(MI->getLength()->getType())); 241 return MI; 242 } 243 244 // Extract the length and alignment and fill if they are constant. 245 ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength()); 246 ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue()); 247 if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8)) 248 return nullptr; 249 const uint64_t Len = LenC->getLimitedValue(); 250 assert(Len && "0-sized memory setting should be removed already."); 251 const Align Alignment = MI->getDestAlign().valueOrOne(); 252 253 // If it is an atomic and alignment is less than the size then we will 254 // introduce the unaligned memory access which will be later transformed 255 // into libcall in CodeGen. This is not evident performance gain so disable 256 // it now. 257 if (isa<AtomicMemSetInst>(MI)) 258 if (Alignment < Len) 259 return nullptr; 260 261 // memset(s,c,n) -> store s, c (for n=1,2,4,8) 262 if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) { 263 Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8. 264 265 Value *Dest = MI->getDest(); 266 267 // Extract the fill value and store. 268 const uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL; 269 Constant *FillVal = ConstantInt::get(ITy, Fill); 270 StoreInst *S = Builder.CreateStore(FillVal, Dest, MI->isVolatile()); 271 S->copyMetadata(*MI, LLVMContext::MD_DIAssignID); 272 auto replaceOpForAssignmentMarkers = [FillC, FillVal](auto *DbgAssign) { 273 if (llvm::is_contained(DbgAssign->location_ops(), FillC)) 274 DbgAssign->replaceVariableLocationOp(FillC, FillVal); 275 }; 276 for_each(at::getAssignmentMarkers(S), replaceOpForAssignmentMarkers); 277 for_each(at::getDVRAssignmentMarkers(S), replaceOpForAssignmentMarkers); 278 279 S->setAlignment(Alignment); 280 if (isa<AtomicMemSetInst>(MI)) 281 S->setOrdering(AtomicOrdering::Unordered); 282 283 // Set the size of the copy to 0, it will be deleted on the next iteration. 284 MI->setLength(Constant::getNullValue(LenC->getType())); 285 return MI; 286 } 287 288 return nullptr; 289 } 290 291 // TODO, Obvious Missing Transforms: 292 // * Narrow width by halfs excluding zero/undef lanes 293 Value *InstCombinerImpl::simplifyMaskedLoad(IntrinsicInst &II) { 294 Value *LoadPtr = II.getArgOperand(0); 295 const Align Alignment = 296 cast<ConstantInt>(II.getArgOperand(1))->getAlignValue(); 297 298 // If the mask is all ones or undefs, this is a plain vector load of the 1st 299 // argument. 300 if (maskIsAllOneOrUndef(II.getArgOperand(2))) { 301 LoadInst *L = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment, 302 "unmaskedload"); 303 L->copyMetadata(II); 304 return L; 305 } 306 307 // If we can unconditionally load from this address, replace with a 308 // load/select idiom. TODO: use DT for context sensitive query 309 if (isDereferenceablePointer(LoadPtr, II.getType(), 310 II.getDataLayout(), &II, &AC)) { 311 LoadInst *LI = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment, 312 "unmaskedload"); 313 LI->copyMetadata(II); 314 return Builder.CreateSelect(II.getArgOperand(2), LI, II.getArgOperand(3)); 315 } 316 317 return nullptr; 318 } 319 320 // TODO, Obvious Missing Transforms: 321 // * Single constant active lane -> store 322 // * Narrow width by halfs excluding zero/undef lanes 323 Instruction *InstCombinerImpl::simplifyMaskedStore(IntrinsicInst &II) { 324 auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(3)); 325 if (!ConstMask) 326 return nullptr; 327 328 // If the mask is all zeros, this instruction does nothing. 329 if (ConstMask->isNullValue()) 330 return eraseInstFromFunction(II); 331 332 // If the mask is all ones, this is a plain vector store of the 1st argument. 333 if (ConstMask->isAllOnesValue()) { 334 Value *StorePtr = II.getArgOperand(1); 335 Align Alignment = cast<ConstantInt>(II.getArgOperand(2))->getAlignValue(); 336 StoreInst *S = 337 new StoreInst(II.getArgOperand(0), StorePtr, false, Alignment); 338 S->copyMetadata(II); 339 return S; 340 } 341 342 if (isa<ScalableVectorType>(ConstMask->getType())) 343 return nullptr; 344 345 // Use masked off lanes to simplify operands via SimplifyDemandedVectorElts 346 APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask); 347 APInt PoisonElts(DemandedElts.getBitWidth(), 0); 348 if (Value *V = SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts, 349 PoisonElts)) 350 return replaceOperand(II, 0, V); 351 352 return nullptr; 353 } 354 355 // TODO, Obvious Missing Transforms: 356 // * Single constant active lane load -> load 357 // * Dereferenceable address & few lanes -> scalarize speculative load/selects 358 // * Adjacent vector addresses -> masked.load 359 // * Narrow width by halfs excluding zero/undef lanes 360 // * Vector incrementing address -> vector masked load 361 Instruction *InstCombinerImpl::simplifyMaskedGather(IntrinsicInst &II) { 362 auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(2)); 363 if (!ConstMask) 364 return nullptr; 365 366 // Vector splat address w/known mask -> scalar load 367 // Fold the gather to load the source vector first lane 368 // because it is reloading the same value each time 369 if (ConstMask->isAllOnesValue()) 370 if (auto *SplatPtr = getSplatValue(II.getArgOperand(0))) { 371 auto *VecTy = cast<VectorType>(II.getType()); 372 const Align Alignment = 373 cast<ConstantInt>(II.getArgOperand(1))->getAlignValue(); 374 LoadInst *L = Builder.CreateAlignedLoad(VecTy->getElementType(), SplatPtr, 375 Alignment, "load.scalar"); 376 Value *Shuf = 377 Builder.CreateVectorSplat(VecTy->getElementCount(), L, "broadcast"); 378 return replaceInstUsesWith(II, cast<Instruction>(Shuf)); 379 } 380 381 return nullptr; 382 } 383 384 // TODO, Obvious Missing Transforms: 385 // * Single constant active lane -> store 386 // * Adjacent vector addresses -> masked.store 387 // * Narrow store width by halfs excluding zero/undef lanes 388 // * Vector incrementing address -> vector masked store 389 Instruction *InstCombinerImpl::simplifyMaskedScatter(IntrinsicInst &II) { 390 auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(3)); 391 if (!ConstMask) 392 return nullptr; 393 394 // If the mask is all zeros, a scatter does nothing. 395 if (ConstMask->isNullValue()) 396 return eraseInstFromFunction(II); 397 398 // Vector splat address -> scalar store 399 if (auto *SplatPtr = getSplatValue(II.getArgOperand(1))) { 400 // scatter(splat(value), splat(ptr), non-zero-mask) -> store value, ptr 401 if (auto *SplatValue = getSplatValue(II.getArgOperand(0))) { 402 if (maskContainsAllOneOrUndef(ConstMask)) { 403 Align Alignment = 404 cast<ConstantInt>(II.getArgOperand(2))->getAlignValue(); 405 StoreInst *S = new StoreInst(SplatValue, SplatPtr, /*IsVolatile=*/false, 406 Alignment); 407 S->copyMetadata(II); 408 return S; 409 } 410 } 411 // scatter(vector, splat(ptr), splat(true)) -> store extract(vector, 412 // lastlane), ptr 413 if (ConstMask->isAllOnesValue()) { 414 Align Alignment = cast<ConstantInt>(II.getArgOperand(2))->getAlignValue(); 415 VectorType *WideLoadTy = cast<VectorType>(II.getArgOperand(1)->getType()); 416 ElementCount VF = WideLoadTy->getElementCount(); 417 Value *RunTimeVF = Builder.CreateElementCount(Builder.getInt32Ty(), VF); 418 Value *LastLane = Builder.CreateSub(RunTimeVF, Builder.getInt32(1)); 419 Value *Extract = 420 Builder.CreateExtractElement(II.getArgOperand(0), LastLane); 421 StoreInst *S = 422 new StoreInst(Extract, SplatPtr, /*IsVolatile=*/false, Alignment); 423 S->copyMetadata(II); 424 return S; 425 } 426 } 427 if (isa<ScalableVectorType>(ConstMask->getType())) 428 return nullptr; 429 430 // Use masked off lanes to simplify operands via SimplifyDemandedVectorElts 431 APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask); 432 APInt PoisonElts(DemandedElts.getBitWidth(), 0); 433 if (Value *V = SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts, 434 PoisonElts)) 435 return replaceOperand(II, 0, V); 436 if (Value *V = SimplifyDemandedVectorElts(II.getOperand(1), DemandedElts, 437 PoisonElts)) 438 return replaceOperand(II, 1, V); 439 440 return nullptr; 441 } 442 443 /// This function transforms launder.invariant.group and strip.invariant.group 444 /// like: 445 /// launder(launder(%x)) -> launder(%x) (the result is not the argument) 446 /// launder(strip(%x)) -> launder(%x) 447 /// strip(strip(%x)) -> strip(%x) (the result is not the argument) 448 /// strip(launder(%x)) -> strip(%x) 449 /// This is legal because it preserves the most recent information about 450 /// the presence or absence of invariant.group. 451 static Instruction *simplifyInvariantGroupIntrinsic(IntrinsicInst &II, 452 InstCombinerImpl &IC) { 453 auto *Arg = II.getArgOperand(0); 454 auto *StrippedArg = Arg->stripPointerCasts(); 455 auto *StrippedInvariantGroupsArg = StrippedArg; 456 while (auto *Intr = dyn_cast<IntrinsicInst>(StrippedInvariantGroupsArg)) { 457 if (Intr->getIntrinsicID() != Intrinsic::launder_invariant_group && 458 Intr->getIntrinsicID() != Intrinsic::strip_invariant_group) 459 break; 460 StrippedInvariantGroupsArg = Intr->getArgOperand(0)->stripPointerCasts(); 461 } 462 if (StrippedArg == StrippedInvariantGroupsArg) 463 return nullptr; // No launders/strips to remove. 464 465 Value *Result = nullptr; 466 467 if (II.getIntrinsicID() == Intrinsic::launder_invariant_group) 468 Result = IC.Builder.CreateLaunderInvariantGroup(StrippedInvariantGroupsArg); 469 else if (II.getIntrinsicID() == Intrinsic::strip_invariant_group) 470 Result = IC.Builder.CreateStripInvariantGroup(StrippedInvariantGroupsArg); 471 else 472 llvm_unreachable( 473 "simplifyInvariantGroupIntrinsic only handles launder and strip"); 474 if (Result->getType()->getPointerAddressSpace() != 475 II.getType()->getPointerAddressSpace()) 476 Result = IC.Builder.CreateAddrSpaceCast(Result, II.getType()); 477 478 return cast<Instruction>(Result); 479 } 480 481 static Instruction *foldCttzCtlz(IntrinsicInst &II, InstCombinerImpl &IC) { 482 assert((II.getIntrinsicID() == Intrinsic::cttz || 483 II.getIntrinsicID() == Intrinsic::ctlz) && 484 "Expected cttz or ctlz intrinsic"); 485 bool IsTZ = II.getIntrinsicID() == Intrinsic::cttz; 486 Value *Op0 = II.getArgOperand(0); 487 Value *Op1 = II.getArgOperand(1); 488 Value *X; 489 // ctlz(bitreverse(x)) -> cttz(x) 490 // cttz(bitreverse(x)) -> ctlz(x) 491 if (match(Op0, m_BitReverse(m_Value(X)))) { 492 Intrinsic::ID ID = IsTZ ? Intrinsic::ctlz : Intrinsic::cttz; 493 Function *F = Intrinsic::getDeclaration(II.getModule(), ID, II.getType()); 494 return CallInst::Create(F, {X, II.getArgOperand(1)}); 495 } 496 497 if (II.getType()->isIntOrIntVectorTy(1)) { 498 // ctlz/cttz i1 Op0 --> not Op0 499 if (match(Op1, m_Zero())) 500 return BinaryOperator::CreateNot(Op0); 501 // If zero is poison, then the input can be assumed to be "true", so the 502 // instruction simplifies to "false". 503 assert(match(Op1, m_One()) && "Expected ctlz/cttz operand to be 0 or 1"); 504 return IC.replaceInstUsesWith(II, ConstantInt::getNullValue(II.getType())); 505 } 506 507 // If ctlz/cttz is only used as a shift amount, set is_zero_poison to true. 508 if (II.hasOneUse() && match(Op1, m_Zero()) && 509 match(II.user_back(), m_Shift(m_Value(), m_Specific(&II)))) { 510 II.dropUBImplyingAttrsAndMetadata(); 511 return IC.replaceOperand(II, 1, IC.Builder.getTrue()); 512 } 513 514 Constant *C; 515 516 if (IsTZ) { 517 // cttz(-x) -> cttz(x) 518 if (match(Op0, m_Neg(m_Value(X)))) 519 return IC.replaceOperand(II, 0, X); 520 521 // cttz(-x & x) -> cttz(x) 522 if (match(Op0, m_c_And(m_Neg(m_Value(X)), m_Deferred(X)))) 523 return IC.replaceOperand(II, 0, X); 524 525 // cttz(sext(x)) -> cttz(zext(x)) 526 if (match(Op0, m_OneUse(m_SExt(m_Value(X))))) { 527 auto *Zext = IC.Builder.CreateZExt(X, II.getType()); 528 auto *CttzZext = 529 IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, Zext, Op1); 530 return IC.replaceInstUsesWith(II, CttzZext); 531 } 532 533 // Zext doesn't change the number of trailing zeros, so narrow: 534 // cttz(zext(x)) -> zext(cttz(x)) if the 'ZeroIsPoison' parameter is 'true'. 535 if (match(Op0, m_OneUse(m_ZExt(m_Value(X)))) && match(Op1, m_One())) { 536 auto *Cttz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, X, 537 IC.Builder.getTrue()); 538 auto *ZextCttz = IC.Builder.CreateZExt(Cttz, II.getType()); 539 return IC.replaceInstUsesWith(II, ZextCttz); 540 } 541 542 // cttz(abs(x)) -> cttz(x) 543 // cttz(nabs(x)) -> cttz(x) 544 Value *Y; 545 SelectPatternFlavor SPF = matchSelectPattern(Op0, X, Y).Flavor; 546 if (SPF == SPF_ABS || SPF == SPF_NABS) 547 return IC.replaceOperand(II, 0, X); 548 549 if (match(Op0, m_Intrinsic<Intrinsic::abs>(m_Value(X)))) 550 return IC.replaceOperand(II, 0, X); 551 552 // cttz(shl(%const, %val), 1) --> add(cttz(%const, 1), %val) 553 if (match(Op0, m_Shl(m_ImmConstant(C), m_Value(X))) && 554 match(Op1, m_One())) { 555 Value *ConstCttz = 556 IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, C, Op1); 557 return BinaryOperator::CreateAdd(ConstCttz, X); 558 } 559 560 // cttz(lshr exact (%const, %val), 1) --> sub(cttz(%const, 1), %val) 561 if (match(Op0, m_Exact(m_LShr(m_ImmConstant(C), m_Value(X)))) && 562 match(Op1, m_One())) { 563 Value *ConstCttz = 564 IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, C, Op1); 565 return BinaryOperator::CreateSub(ConstCttz, X); 566 } 567 568 // cttz(add(lshr(UINT_MAX, %val), 1)) --> sub(width, %val) 569 if (match(Op0, m_Add(m_LShr(m_AllOnes(), m_Value(X)), m_One()))) { 570 Value *Width = 571 ConstantInt::get(II.getType(), II.getType()->getScalarSizeInBits()); 572 return BinaryOperator::CreateSub(Width, X); 573 } 574 } else { 575 // ctlz(lshr(%const, %val), 1) --> add(ctlz(%const, 1), %val) 576 if (match(Op0, m_LShr(m_ImmConstant(C), m_Value(X))) && 577 match(Op1, m_One())) { 578 Value *ConstCtlz = 579 IC.Builder.CreateBinaryIntrinsic(Intrinsic::ctlz, C, Op1); 580 return BinaryOperator::CreateAdd(ConstCtlz, X); 581 } 582 583 // ctlz(shl nuw (%const, %val), 1) --> sub(ctlz(%const, 1), %val) 584 if (match(Op0, m_NUWShl(m_ImmConstant(C), m_Value(X))) && 585 match(Op1, m_One())) { 586 Value *ConstCtlz = 587 IC.Builder.CreateBinaryIntrinsic(Intrinsic::ctlz, C, Op1); 588 return BinaryOperator::CreateSub(ConstCtlz, X); 589 } 590 } 591 592 KnownBits Known = IC.computeKnownBits(Op0, 0, &II); 593 594 // Create a mask for bits above (ctlz) or below (cttz) the first known one. 595 unsigned PossibleZeros = IsTZ ? Known.countMaxTrailingZeros() 596 : Known.countMaxLeadingZeros(); 597 unsigned DefiniteZeros = IsTZ ? Known.countMinTrailingZeros() 598 : Known.countMinLeadingZeros(); 599 600 // If all bits above (ctlz) or below (cttz) the first known one are known 601 // zero, this value is constant. 602 // FIXME: This should be in InstSimplify because we're replacing an 603 // instruction with a constant. 604 if (PossibleZeros == DefiniteZeros) { 605 auto *C = ConstantInt::get(Op0->getType(), DefiniteZeros); 606 return IC.replaceInstUsesWith(II, C); 607 } 608 609 // If the input to cttz/ctlz is known to be non-zero, 610 // then change the 'ZeroIsPoison' parameter to 'true' 611 // because we know the zero behavior can't affect the result. 612 if (!Known.One.isZero() || 613 isKnownNonZero(Op0, IC.getSimplifyQuery().getWithInstruction(&II))) { 614 if (!match(II.getArgOperand(1), m_One())) 615 return IC.replaceOperand(II, 1, IC.Builder.getTrue()); 616 } 617 618 // Add range attribute since known bits can't completely reflect what we know. 619 unsigned BitWidth = Op0->getType()->getScalarSizeInBits(); 620 if (BitWidth != 1 && !II.hasRetAttr(Attribute::Range) && 621 !II.getMetadata(LLVMContext::MD_range)) { 622 ConstantRange Range(APInt(BitWidth, DefiniteZeros), 623 APInt(BitWidth, PossibleZeros + 1)); 624 II.addRangeRetAttr(Range); 625 return &II; 626 } 627 628 return nullptr; 629 } 630 631 static Instruction *foldCtpop(IntrinsicInst &II, InstCombinerImpl &IC) { 632 assert(II.getIntrinsicID() == Intrinsic::ctpop && 633 "Expected ctpop intrinsic"); 634 Type *Ty = II.getType(); 635 unsigned BitWidth = Ty->getScalarSizeInBits(); 636 Value *Op0 = II.getArgOperand(0); 637 Value *X, *Y; 638 639 // ctpop(bitreverse(x)) -> ctpop(x) 640 // ctpop(bswap(x)) -> ctpop(x) 641 if (match(Op0, m_BitReverse(m_Value(X))) || match(Op0, m_BSwap(m_Value(X)))) 642 return IC.replaceOperand(II, 0, X); 643 644 // ctpop(rot(x)) -> ctpop(x) 645 if ((match(Op0, m_FShl(m_Value(X), m_Value(Y), m_Value())) || 646 match(Op0, m_FShr(m_Value(X), m_Value(Y), m_Value()))) && 647 X == Y) 648 return IC.replaceOperand(II, 0, X); 649 650 // ctpop(x | -x) -> bitwidth - cttz(x, false) 651 if (Op0->hasOneUse() && 652 match(Op0, m_c_Or(m_Value(X), m_Neg(m_Deferred(X))))) { 653 Function *F = 654 Intrinsic::getDeclaration(II.getModule(), Intrinsic::cttz, Ty); 655 auto *Cttz = IC.Builder.CreateCall(F, {X, IC.Builder.getFalse()}); 656 auto *Bw = ConstantInt::get(Ty, APInt(BitWidth, BitWidth)); 657 return IC.replaceInstUsesWith(II, IC.Builder.CreateSub(Bw, Cttz)); 658 } 659 660 // ctpop(~x & (x - 1)) -> cttz(x, false) 661 if (match(Op0, 662 m_c_And(m_Not(m_Value(X)), m_Add(m_Deferred(X), m_AllOnes())))) { 663 Function *F = 664 Intrinsic::getDeclaration(II.getModule(), Intrinsic::cttz, Ty); 665 return CallInst::Create(F, {X, IC.Builder.getFalse()}); 666 } 667 668 // Zext doesn't change the number of set bits, so narrow: 669 // ctpop (zext X) --> zext (ctpop X) 670 if (match(Op0, m_OneUse(m_ZExt(m_Value(X))))) { 671 Value *NarrowPop = IC.Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, X); 672 return CastInst::Create(Instruction::ZExt, NarrowPop, Ty); 673 } 674 675 KnownBits Known(BitWidth); 676 IC.computeKnownBits(Op0, Known, 0, &II); 677 678 // If all bits are zero except for exactly one fixed bit, then the result 679 // must be 0 or 1, and we can get that answer by shifting to LSB: 680 // ctpop (X & 32) --> (X & 32) >> 5 681 // TODO: Investigate removing this as its likely unnecessary given the below 682 // `isKnownToBeAPowerOfTwo` check. 683 if ((~Known.Zero).isPowerOf2()) 684 return BinaryOperator::CreateLShr( 685 Op0, ConstantInt::get(Ty, (~Known.Zero).exactLogBase2())); 686 687 // More generally we can also handle non-constant power of 2 patterns such as 688 // shl/shr(Pow2, X), (X & -X), etc... by transforming: 689 // ctpop(Pow2OrZero) --> icmp ne X, 0 690 if (IC.isKnownToBeAPowerOfTwo(Op0, /* OrZero */ true)) 691 return CastInst::Create(Instruction::ZExt, 692 IC.Builder.CreateICmp(ICmpInst::ICMP_NE, Op0, 693 Constant::getNullValue(Ty)), 694 Ty); 695 696 // Add range attribute since known bits can't completely reflect what we know. 697 if (BitWidth != 1 && !II.hasRetAttr(Attribute::Range) && 698 !II.getMetadata(LLVMContext::MD_range)) { 699 ConstantRange Range(APInt(BitWidth, Known.countMinPopulation()), 700 APInt(BitWidth, Known.countMaxPopulation() + 1)); 701 II.addRangeRetAttr(Range); 702 return &II; 703 } 704 705 return nullptr; 706 } 707 708 /// Convert a table lookup to shufflevector if the mask is constant. 709 /// This could benefit tbl1 if the mask is { 7,6,5,4,3,2,1,0 }, in 710 /// which case we could lower the shufflevector with rev64 instructions 711 /// as it's actually a byte reverse. 712 static Value *simplifyNeonTbl1(const IntrinsicInst &II, 713 InstCombiner::BuilderTy &Builder) { 714 // Bail out if the mask is not a constant. 715 auto *C = dyn_cast<Constant>(II.getArgOperand(1)); 716 if (!C) 717 return nullptr; 718 719 auto *VecTy = cast<FixedVectorType>(II.getType()); 720 unsigned NumElts = VecTy->getNumElements(); 721 722 // Only perform this transformation for <8 x i8> vector types. 723 if (!VecTy->getElementType()->isIntegerTy(8) || NumElts != 8) 724 return nullptr; 725 726 int Indexes[8]; 727 728 for (unsigned I = 0; I < NumElts; ++I) { 729 Constant *COp = C->getAggregateElement(I); 730 731 if (!COp || !isa<ConstantInt>(COp)) 732 return nullptr; 733 734 Indexes[I] = cast<ConstantInt>(COp)->getLimitedValue(); 735 736 // Make sure the mask indices are in range. 737 if ((unsigned)Indexes[I] >= NumElts) 738 return nullptr; 739 } 740 741 auto *V1 = II.getArgOperand(0); 742 auto *V2 = Constant::getNullValue(V1->getType()); 743 return Builder.CreateShuffleVector(V1, V2, ArrayRef(Indexes)); 744 } 745 746 // Returns true iff the 2 intrinsics have the same operands, limiting the 747 // comparison to the first NumOperands. 748 static bool haveSameOperands(const IntrinsicInst &I, const IntrinsicInst &E, 749 unsigned NumOperands) { 750 assert(I.arg_size() >= NumOperands && "Not enough operands"); 751 assert(E.arg_size() >= NumOperands && "Not enough operands"); 752 for (unsigned i = 0; i < NumOperands; i++) 753 if (I.getArgOperand(i) != E.getArgOperand(i)) 754 return false; 755 return true; 756 } 757 758 // Remove trivially empty start/end intrinsic ranges, i.e. a start 759 // immediately followed by an end (ignoring debuginfo or other 760 // start/end intrinsics in between). As this handles only the most trivial 761 // cases, tracking the nesting level is not needed: 762 // 763 // call @llvm.foo.start(i1 0) 764 // call @llvm.foo.start(i1 0) ; This one won't be skipped: it will be removed 765 // call @llvm.foo.end(i1 0) 766 // call @llvm.foo.end(i1 0) ; &I 767 static bool 768 removeTriviallyEmptyRange(IntrinsicInst &EndI, InstCombinerImpl &IC, 769 std::function<bool(const IntrinsicInst &)> IsStart) { 770 // We start from the end intrinsic and scan backwards, so that InstCombine 771 // has already processed (and potentially removed) all the instructions 772 // before the end intrinsic. 773 BasicBlock::reverse_iterator BI(EndI), BE(EndI.getParent()->rend()); 774 for (; BI != BE; ++BI) { 775 if (auto *I = dyn_cast<IntrinsicInst>(&*BI)) { 776 if (I->isDebugOrPseudoInst() || 777 I->getIntrinsicID() == EndI.getIntrinsicID()) 778 continue; 779 if (IsStart(*I)) { 780 if (haveSameOperands(EndI, *I, EndI.arg_size())) { 781 IC.eraseInstFromFunction(*I); 782 IC.eraseInstFromFunction(EndI); 783 return true; 784 } 785 // Skip start intrinsics that don't pair with this end intrinsic. 786 continue; 787 } 788 } 789 break; 790 } 791 792 return false; 793 } 794 795 Instruction *InstCombinerImpl::visitVAEndInst(VAEndInst &I) { 796 removeTriviallyEmptyRange(I, *this, [](const IntrinsicInst &I) { 797 return I.getIntrinsicID() == Intrinsic::vastart || 798 I.getIntrinsicID() == Intrinsic::vacopy; 799 }); 800 return nullptr; 801 } 802 803 static CallInst *canonicalizeConstantArg0ToArg1(CallInst &Call) { 804 assert(Call.arg_size() > 1 && "Need at least 2 args to swap"); 805 Value *Arg0 = Call.getArgOperand(0), *Arg1 = Call.getArgOperand(1); 806 if (isa<Constant>(Arg0) && !isa<Constant>(Arg1)) { 807 Call.setArgOperand(0, Arg1); 808 Call.setArgOperand(1, Arg0); 809 return &Call; 810 } 811 return nullptr; 812 } 813 814 /// Creates a result tuple for an overflow intrinsic \p II with a given 815 /// \p Result and a constant \p Overflow value. 816 static Instruction *createOverflowTuple(IntrinsicInst *II, Value *Result, 817 Constant *Overflow) { 818 Constant *V[] = {PoisonValue::get(Result->getType()), Overflow}; 819 StructType *ST = cast<StructType>(II->getType()); 820 Constant *Struct = ConstantStruct::get(ST, V); 821 return InsertValueInst::Create(Struct, Result, 0); 822 } 823 824 Instruction * 825 InstCombinerImpl::foldIntrinsicWithOverflowCommon(IntrinsicInst *II) { 826 WithOverflowInst *WO = cast<WithOverflowInst>(II); 827 Value *OperationResult = nullptr; 828 Constant *OverflowResult = nullptr; 829 if (OptimizeOverflowCheck(WO->getBinaryOp(), WO->isSigned(), WO->getLHS(), 830 WO->getRHS(), *WO, OperationResult, OverflowResult)) 831 return createOverflowTuple(WO, OperationResult, OverflowResult); 832 return nullptr; 833 } 834 835 static bool inputDenormalIsIEEE(const Function &F, const Type *Ty) { 836 Ty = Ty->getScalarType(); 837 return F.getDenormalMode(Ty->getFltSemantics()).Input == DenormalMode::IEEE; 838 } 839 840 static bool inputDenormalIsDAZ(const Function &F, const Type *Ty) { 841 Ty = Ty->getScalarType(); 842 return F.getDenormalMode(Ty->getFltSemantics()).inputsAreZero(); 843 } 844 845 /// \returns the compare predicate type if the test performed by 846 /// llvm.is.fpclass(x, \p Mask) is equivalent to fcmp o__ x, 0.0 with the 847 /// floating-point environment assumed for \p F for type \p Ty 848 static FCmpInst::Predicate fpclassTestIsFCmp0(FPClassTest Mask, 849 const Function &F, Type *Ty) { 850 switch (static_cast<unsigned>(Mask)) { 851 case fcZero: 852 if (inputDenormalIsIEEE(F, Ty)) 853 return FCmpInst::FCMP_OEQ; 854 break; 855 case fcZero | fcSubnormal: 856 if (inputDenormalIsDAZ(F, Ty)) 857 return FCmpInst::FCMP_OEQ; 858 break; 859 case fcPositive | fcNegZero: 860 if (inputDenormalIsIEEE(F, Ty)) 861 return FCmpInst::FCMP_OGE; 862 break; 863 case fcPositive | fcNegZero | fcNegSubnormal: 864 if (inputDenormalIsDAZ(F, Ty)) 865 return FCmpInst::FCMP_OGE; 866 break; 867 case fcPosSubnormal | fcPosNormal | fcPosInf: 868 if (inputDenormalIsIEEE(F, Ty)) 869 return FCmpInst::FCMP_OGT; 870 break; 871 case fcNegative | fcPosZero: 872 if (inputDenormalIsIEEE(F, Ty)) 873 return FCmpInst::FCMP_OLE; 874 break; 875 case fcNegative | fcPosZero | fcPosSubnormal: 876 if (inputDenormalIsDAZ(F, Ty)) 877 return FCmpInst::FCMP_OLE; 878 break; 879 case fcNegSubnormal | fcNegNormal | fcNegInf: 880 if (inputDenormalIsIEEE(F, Ty)) 881 return FCmpInst::FCMP_OLT; 882 break; 883 case fcPosNormal | fcPosInf: 884 if (inputDenormalIsDAZ(F, Ty)) 885 return FCmpInst::FCMP_OGT; 886 break; 887 case fcNegNormal | fcNegInf: 888 if (inputDenormalIsDAZ(F, Ty)) 889 return FCmpInst::FCMP_OLT; 890 break; 891 case ~fcZero & ~fcNan: 892 if (inputDenormalIsIEEE(F, Ty)) 893 return FCmpInst::FCMP_ONE; 894 break; 895 case ~(fcZero | fcSubnormal) & ~fcNan: 896 if (inputDenormalIsDAZ(F, Ty)) 897 return FCmpInst::FCMP_ONE; 898 break; 899 default: 900 break; 901 } 902 903 return FCmpInst::BAD_FCMP_PREDICATE; 904 } 905 906 Instruction *InstCombinerImpl::foldIntrinsicIsFPClass(IntrinsicInst &II) { 907 Value *Src0 = II.getArgOperand(0); 908 Value *Src1 = II.getArgOperand(1); 909 const ConstantInt *CMask = cast<ConstantInt>(Src1); 910 FPClassTest Mask = static_cast<FPClassTest>(CMask->getZExtValue()); 911 const bool IsUnordered = (Mask & fcNan) == fcNan; 912 const bool IsOrdered = (Mask & fcNan) == fcNone; 913 const FPClassTest OrderedMask = Mask & ~fcNan; 914 const FPClassTest OrderedInvertedMask = ~OrderedMask & ~fcNan; 915 916 const bool IsStrict = 917 II.getFunction()->getAttributes().hasFnAttr(Attribute::StrictFP); 918 919 Value *FNegSrc; 920 if (match(Src0, m_FNeg(m_Value(FNegSrc)))) { 921 // is.fpclass (fneg x), mask -> is.fpclass x, (fneg mask) 922 923 II.setArgOperand(1, ConstantInt::get(Src1->getType(), fneg(Mask))); 924 return replaceOperand(II, 0, FNegSrc); 925 } 926 927 Value *FAbsSrc; 928 if (match(Src0, m_FAbs(m_Value(FAbsSrc)))) { 929 II.setArgOperand(1, ConstantInt::get(Src1->getType(), inverse_fabs(Mask))); 930 return replaceOperand(II, 0, FAbsSrc); 931 } 932 933 if ((OrderedMask == fcInf || OrderedInvertedMask == fcInf) && 934 (IsOrdered || IsUnordered) && !IsStrict) { 935 // is.fpclass(x, fcInf) -> fcmp oeq fabs(x), +inf 936 // is.fpclass(x, ~fcInf) -> fcmp one fabs(x), +inf 937 // is.fpclass(x, fcInf|fcNan) -> fcmp ueq fabs(x), +inf 938 // is.fpclass(x, ~(fcInf|fcNan)) -> fcmp une fabs(x), +inf 939 Constant *Inf = ConstantFP::getInfinity(Src0->getType()); 940 FCmpInst::Predicate Pred = 941 IsUnordered ? FCmpInst::FCMP_UEQ : FCmpInst::FCMP_OEQ; 942 if (OrderedInvertedMask == fcInf) 943 Pred = IsUnordered ? FCmpInst::FCMP_UNE : FCmpInst::FCMP_ONE; 944 945 Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Src0); 946 Value *CmpInf = Builder.CreateFCmp(Pred, Fabs, Inf); 947 CmpInf->takeName(&II); 948 return replaceInstUsesWith(II, CmpInf); 949 } 950 951 if ((OrderedMask == fcPosInf || OrderedMask == fcNegInf) && 952 (IsOrdered || IsUnordered) && !IsStrict) { 953 // is.fpclass(x, fcPosInf) -> fcmp oeq x, +inf 954 // is.fpclass(x, fcNegInf) -> fcmp oeq x, -inf 955 // is.fpclass(x, fcPosInf|fcNan) -> fcmp ueq x, +inf 956 // is.fpclass(x, fcNegInf|fcNan) -> fcmp ueq x, -inf 957 Constant *Inf = 958 ConstantFP::getInfinity(Src0->getType(), OrderedMask == fcNegInf); 959 Value *EqInf = IsUnordered ? Builder.CreateFCmpUEQ(Src0, Inf) 960 : Builder.CreateFCmpOEQ(Src0, Inf); 961 962 EqInf->takeName(&II); 963 return replaceInstUsesWith(II, EqInf); 964 } 965 966 if ((OrderedInvertedMask == fcPosInf || OrderedInvertedMask == fcNegInf) && 967 (IsOrdered || IsUnordered) && !IsStrict) { 968 // is.fpclass(x, ~fcPosInf) -> fcmp one x, +inf 969 // is.fpclass(x, ~fcNegInf) -> fcmp one x, -inf 970 // is.fpclass(x, ~fcPosInf|fcNan) -> fcmp une x, +inf 971 // is.fpclass(x, ~fcNegInf|fcNan) -> fcmp une x, -inf 972 Constant *Inf = ConstantFP::getInfinity(Src0->getType(), 973 OrderedInvertedMask == fcNegInf); 974 Value *NeInf = IsUnordered ? Builder.CreateFCmpUNE(Src0, Inf) 975 : Builder.CreateFCmpONE(Src0, Inf); 976 NeInf->takeName(&II); 977 return replaceInstUsesWith(II, NeInf); 978 } 979 980 if (Mask == fcNan && !IsStrict) { 981 // Equivalent of isnan. Replace with standard fcmp if we don't care about FP 982 // exceptions. 983 Value *IsNan = 984 Builder.CreateFCmpUNO(Src0, ConstantFP::getZero(Src0->getType())); 985 IsNan->takeName(&II); 986 return replaceInstUsesWith(II, IsNan); 987 } 988 989 if (Mask == (~fcNan & fcAllFlags) && !IsStrict) { 990 // Equivalent of !isnan. Replace with standard fcmp. 991 Value *FCmp = 992 Builder.CreateFCmpORD(Src0, ConstantFP::getZero(Src0->getType())); 993 FCmp->takeName(&II); 994 return replaceInstUsesWith(II, FCmp); 995 } 996 997 FCmpInst::Predicate PredType = FCmpInst::BAD_FCMP_PREDICATE; 998 999 // Try to replace with an fcmp with 0 1000 // 1001 // is.fpclass(x, fcZero) -> fcmp oeq x, 0.0 1002 // is.fpclass(x, fcZero | fcNan) -> fcmp ueq x, 0.0 1003 // is.fpclass(x, ~fcZero & ~fcNan) -> fcmp one x, 0.0 1004 // is.fpclass(x, ~fcZero) -> fcmp une x, 0.0 1005 // 1006 // is.fpclass(x, fcPosSubnormal | fcPosNormal | fcPosInf) -> fcmp ogt x, 0.0 1007 // is.fpclass(x, fcPositive | fcNegZero) -> fcmp oge x, 0.0 1008 // 1009 // is.fpclass(x, fcNegSubnormal | fcNegNormal | fcNegInf) -> fcmp olt x, 0.0 1010 // is.fpclass(x, fcNegative | fcPosZero) -> fcmp ole x, 0.0 1011 // 1012 if (!IsStrict && (IsOrdered || IsUnordered) && 1013 (PredType = fpclassTestIsFCmp0(OrderedMask, *II.getFunction(), 1014 Src0->getType())) != 1015 FCmpInst::BAD_FCMP_PREDICATE) { 1016 Constant *Zero = ConstantFP::getZero(Src0->getType()); 1017 // Equivalent of == 0. 1018 Value *FCmp = Builder.CreateFCmp( 1019 IsUnordered ? FCmpInst::getUnorderedPredicate(PredType) : PredType, 1020 Src0, Zero); 1021 1022 FCmp->takeName(&II); 1023 return replaceInstUsesWith(II, FCmp); 1024 } 1025 1026 KnownFPClass Known = computeKnownFPClass(Src0, Mask, &II); 1027 1028 // Clear test bits we know must be false from the source value. 1029 // fp_class (nnan x), qnan|snan|other -> fp_class (nnan x), other 1030 // fp_class (ninf x), ninf|pinf|other -> fp_class (ninf x), other 1031 if ((Mask & Known.KnownFPClasses) != Mask) { 1032 II.setArgOperand( 1033 1, ConstantInt::get(Src1->getType(), Mask & Known.KnownFPClasses)); 1034 return &II; 1035 } 1036 1037 // If none of the tests which can return false are possible, fold to true. 1038 // fp_class (nnan x), ~(qnan|snan) -> true 1039 // fp_class (ninf x), ~(ninf|pinf) -> true 1040 if (Mask == Known.KnownFPClasses) 1041 return replaceInstUsesWith(II, ConstantInt::get(II.getType(), true)); 1042 1043 return nullptr; 1044 } 1045 1046 static std::optional<bool> getKnownSign(Value *Op, const SimplifyQuery &SQ) { 1047 KnownBits Known = computeKnownBits(Op, /*Depth=*/0, SQ); 1048 if (Known.isNonNegative()) 1049 return false; 1050 if (Known.isNegative()) 1051 return true; 1052 1053 Value *X, *Y; 1054 if (match(Op, m_NSWSub(m_Value(X), m_Value(Y)))) 1055 return isImpliedByDomCondition(ICmpInst::ICMP_SLT, X, Y, SQ.CxtI, SQ.DL); 1056 1057 return std::nullopt; 1058 } 1059 1060 static std::optional<bool> getKnownSignOrZero(Value *Op, 1061 const SimplifyQuery &SQ) { 1062 if (std::optional<bool> Sign = getKnownSign(Op, SQ)) 1063 return Sign; 1064 1065 Value *X, *Y; 1066 if (match(Op, m_NSWSub(m_Value(X), m_Value(Y)))) 1067 return isImpliedByDomCondition(ICmpInst::ICMP_SLE, X, Y, SQ.CxtI, SQ.DL); 1068 1069 return std::nullopt; 1070 } 1071 1072 /// Return true if two values \p Op0 and \p Op1 are known to have the same sign. 1073 static bool signBitMustBeTheSame(Value *Op0, Value *Op1, 1074 const SimplifyQuery &SQ) { 1075 std::optional<bool> Known1 = getKnownSign(Op1, SQ); 1076 if (!Known1) 1077 return false; 1078 std::optional<bool> Known0 = getKnownSign(Op0, SQ); 1079 if (!Known0) 1080 return false; 1081 return *Known0 == *Known1; 1082 } 1083 1084 /// Try to canonicalize min/max(X + C0, C1) as min/max(X, C1 - C0) + C0. This 1085 /// can trigger other combines. 1086 static Instruction *moveAddAfterMinMax(IntrinsicInst *II, 1087 InstCombiner::BuilderTy &Builder) { 1088 Intrinsic::ID MinMaxID = II->getIntrinsicID(); 1089 assert((MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin || 1090 MinMaxID == Intrinsic::umax || MinMaxID == Intrinsic::umin) && 1091 "Expected a min or max intrinsic"); 1092 1093 // TODO: Match vectors with undef elements, but undef may not propagate. 1094 Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1); 1095 Value *X; 1096 const APInt *C0, *C1; 1097 if (!match(Op0, m_OneUse(m_Add(m_Value(X), m_APInt(C0)))) || 1098 !match(Op1, m_APInt(C1))) 1099 return nullptr; 1100 1101 // Check for necessary no-wrap and overflow constraints. 1102 bool IsSigned = MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin; 1103 auto *Add = cast<BinaryOperator>(Op0); 1104 if ((IsSigned && !Add->hasNoSignedWrap()) || 1105 (!IsSigned && !Add->hasNoUnsignedWrap())) 1106 return nullptr; 1107 1108 // If the constant difference overflows, then instsimplify should reduce the 1109 // min/max to the add or C1. 1110 bool Overflow; 1111 APInt CDiff = 1112 IsSigned ? C1->ssub_ov(*C0, Overflow) : C1->usub_ov(*C0, Overflow); 1113 assert(!Overflow && "Expected simplify of min/max"); 1114 1115 // min/max (add X, C0), C1 --> add (min/max X, C1 - C0), C0 1116 // Note: the "mismatched" no-overflow setting does not propagate. 1117 Constant *NewMinMaxC = ConstantInt::get(II->getType(), CDiff); 1118 Value *NewMinMax = Builder.CreateBinaryIntrinsic(MinMaxID, X, NewMinMaxC); 1119 return IsSigned ? BinaryOperator::CreateNSWAdd(NewMinMax, Add->getOperand(1)) 1120 : BinaryOperator::CreateNUWAdd(NewMinMax, Add->getOperand(1)); 1121 } 1122 /// Match a sadd_sat or ssub_sat which is using min/max to clamp the value. 1123 Instruction *InstCombinerImpl::matchSAddSubSat(IntrinsicInst &MinMax1) { 1124 Type *Ty = MinMax1.getType(); 1125 1126 // We are looking for a tree of: 1127 // max(INT_MIN, min(INT_MAX, add(sext(A), sext(B)))) 1128 // Where the min and max could be reversed 1129 Instruction *MinMax2; 1130 BinaryOperator *AddSub; 1131 const APInt *MinValue, *MaxValue; 1132 if (match(&MinMax1, m_SMin(m_Instruction(MinMax2), m_APInt(MaxValue)))) { 1133 if (!match(MinMax2, m_SMax(m_BinOp(AddSub), m_APInt(MinValue)))) 1134 return nullptr; 1135 } else if (match(&MinMax1, 1136 m_SMax(m_Instruction(MinMax2), m_APInt(MinValue)))) { 1137 if (!match(MinMax2, m_SMin(m_BinOp(AddSub), m_APInt(MaxValue)))) 1138 return nullptr; 1139 } else 1140 return nullptr; 1141 1142 // Check that the constants clamp a saturate, and that the new type would be 1143 // sensible to convert to. 1144 if (!(*MaxValue + 1).isPowerOf2() || -*MinValue != *MaxValue + 1) 1145 return nullptr; 1146 // In what bitwidth can this be treated as saturating arithmetics? 1147 unsigned NewBitWidth = (*MaxValue + 1).logBase2() + 1; 1148 // FIXME: This isn't quite right for vectors, but using the scalar type is a 1149 // good first approximation for what should be done there. 1150 if (!shouldChangeType(Ty->getScalarType()->getIntegerBitWidth(), NewBitWidth)) 1151 return nullptr; 1152 1153 // Also make sure that the inner min/max and the add/sub have one use. 1154 if (!MinMax2->hasOneUse() || !AddSub->hasOneUse()) 1155 return nullptr; 1156 1157 // Create the new type (which can be a vector type) 1158 Type *NewTy = Ty->getWithNewBitWidth(NewBitWidth); 1159 1160 Intrinsic::ID IntrinsicID; 1161 if (AddSub->getOpcode() == Instruction::Add) 1162 IntrinsicID = Intrinsic::sadd_sat; 1163 else if (AddSub->getOpcode() == Instruction::Sub) 1164 IntrinsicID = Intrinsic::ssub_sat; 1165 else 1166 return nullptr; 1167 1168 // The two operands of the add/sub must be nsw-truncatable to the NewTy. This 1169 // is usually achieved via a sext from a smaller type. 1170 if (ComputeMaxSignificantBits(AddSub->getOperand(0), 0, AddSub) > 1171 NewBitWidth || 1172 ComputeMaxSignificantBits(AddSub->getOperand(1), 0, AddSub) > NewBitWidth) 1173 return nullptr; 1174 1175 // Finally create and return the sat intrinsic, truncated to the new type 1176 Function *F = Intrinsic::getDeclaration(MinMax1.getModule(), IntrinsicID, NewTy); 1177 Value *AT = Builder.CreateTrunc(AddSub->getOperand(0), NewTy); 1178 Value *BT = Builder.CreateTrunc(AddSub->getOperand(1), NewTy); 1179 Value *Sat = Builder.CreateCall(F, {AT, BT}); 1180 return CastInst::Create(Instruction::SExt, Sat, Ty); 1181 } 1182 1183 1184 /// If we have a clamp pattern like max (min X, 42), 41 -- where the output 1185 /// can only be one of two possible constant values -- turn that into a select 1186 /// of constants. 1187 static Instruction *foldClampRangeOfTwo(IntrinsicInst *II, 1188 InstCombiner::BuilderTy &Builder) { 1189 Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); 1190 Value *X; 1191 const APInt *C0, *C1; 1192 if (!match(I1, m_APInt(C1)) || !I0->hasOneUse()) 1193 return nullptr; 1194 1195 CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE; 1196 switch (II->getIntrinsicID()) { 1197 case Intrinsic::smax: 1198 if (match(I0, m_SMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1) 1199 Pred = ICmpInst::ICMP_SGT; 1200 break; 1201 case Intrinsic::smin: 1202 if (match(I0, m_SMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1) 1203 Pred = ICmpInst::ICMP_SLT; 1204 break; 1205 case Intrinsic::umax: 1206 if (match(I0, m_UMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1) 1207 Pred = ICmpInst::ICMP_UGT; 1208 break; 1209 case Intrinsic::umin: 1210 if (match(I0, m_UMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1) 1211 Pred = ICmpInst::ICMP_ULT; 1212 break; 1213 default: 1214 llvm_unreachable("Expected min/max intrinsic"); 1215 } 1216 if (Pred == CmpInst::BAD_ICMP_PREDICATE) 1217 return nullptr; 1218 1219 // max (min X, 42), 41 --> X > 41 ? 42 : 41 1220 // min (max X, 42), 43 --> X < 43 ? 42 : 43 1221 Value *Cmp = Builder.CreateICmp(Pred, X, I1); 1222 return SelectInst::Create(Cmp, ConstantInt::get(II->getType(), *C0), I1); 1223 } 1224 1225 /// If this min/max has a constant operand and an operand that is a matching 1226 /// min/max with a constant operand, constant-fold the 2 constant operands. 1227 static Value *reassociateMinMaxWithConstants(IntrinsicInst *II, 1228 IRBuilderBase &Builder, 1229 const SimplifyQuery &SQ) { 1230 Intrinsic::ID MinMaxID = II->getIntrinsicID(); 1231 auto *LHS = dyn_cast<MinMaxIntrinsic>(II->getArgOperand(0)); 1232 if (!LHS) 1233 return nullptr; 1234 1235 Constant *C0, *C1; 1236 if (!match(LHS->getArgOperand(1), m_ImmConstant(C0)) || 1237 !match(II->getArgOperand(1), m_ImmConstant(C1))) 1238 return nullptr; 1239 1240 // max (max X, C0), C1 --> max X, (max C0, C1) 1241 // min (min X, C0), C1 --> min X, (min C0, C1) 1242 // umax (smax X, nneg C0), nneg C1 --> smax X, (umax C0, C1) 1243 // smin (umin X, nneg C0), nneg C1 --> umin X, (smin C0, C1) 1244 Intrinsic::ID InnerMinMaxID = LHS->getIntrinsicID(); 1245 if (InnerMinMaxID != MinMaxID && 1246 !(((MinMaxID == Intrinsic::umax && InnerMinMaxID == Intrinsic::smax) || 1247 (MinMaxID == Intrinsic::smin && InnerMinMaxID == Intrinsic::umin)) && 1248 isKnownNonNegative(C0, SQ) && isKnownNonNegative(C1, SQ))) 1249 return nullptr; 1250 1251 ICmpInst::Predicate Pred = MinMaxIntrinsic::getPredicate(MinMaxID); 1252 Value *CondC = Builder.CreateICmp(Pred, C0, C1); 1253 Value *NewC = Builder.CreateSelect(CondC, C0, C1); 1254 return Builder.CreateIntrinsic(InnerMinMaxID, II->getType(), 1255 {LHS->getArgOperand(0), NewC}); 1256 } 1257 1258 /// If this min/max has a matching min/max operand with a constant, try to push 1259 /// the constant operand into this instruction. This can enable more folds. 1260 static Instruction * 1261 reassociateMinMaxWithConstantInOperand(IntrinsicInst *II, 1262 InstCombiner::BuilderTy &Builder) { 1263 // Match and capture a min/max operand candidate. 1264 Value *X, *Y; 1265 Constant *C; 1266 Instruction *Inner; 1267 if (!match(II, m_c_MaxOrMin(m_OneUse(m_CombineAnd( 1268 m_Instruction(Inner), 1269 m_MaxOrMin(m_Value(X), m_ImmConstant(C)))), 1270 m_Value(Y)))) 1271 return nullptr; 1272 1273 // The inner op must match. Check for constants to avoid infinite loops. 1274 Intrinsic::ID MinMaxID = II->getIntrinsicID(); 1275 auto *InnerMM = dyn_cast<IntrinsicInst>(Inner); 1276 if (!InnerMM || InnerMM->getIntrinsicID() != MinMaxID || 1277 match(X, m_ImmConstant()) || match(Y, m_ImmConstant())) 1278 return nullptr; 1279 1280 // max (max X, C), Y --> max (max X, Y), C 1281 Function *MinMax = 1282 Intrinsic::getDeclaration(II->getModule(), MinMaxID, II->getType()); 1283 Value *NewInner = Builder.CreateBinaryIntrinsic(MinMaxID, X, Y); 1284 NewInner->takeName(Inner); 1285 return CallInst::Create(MinMax, {NewInner, C}); 1286 } 1287 1288 /// Reduce a sequence of min/max intrinsics with a common operand. 1289 static Instruction *factorizeMinMaxTree(IntrinsicInst *II) { 1290 // Match 3 of the same min/max ops. Example: umin(umin(), umin()). 1291 auto *LHS = dyn_cast<IntrinsicInst>(II->getArgOperand(0)); 1292 auto *RHS = dyn_cast<IntrinsicInst>(II->getArgOperand(1)); 1293 Intrinsic::ID MinMaxID = II->getIntrinsicID(); 1294 if (!LHS || !RHS || LHS->getIntrinsicID() != MinMaxID || 1295 RHS->getIntrinsicID() != MinMaxID || 1296 (!LHS->hasOneUse() && !RHS->hasOneUse())) 1297 return nullptr; 1298 1299 Value *A = LHS->getArgOperand(0); 1300 Value *B = LHS->getArgOperand(1); 1301 Value *C = RHS->getArgOperand(0); 1302 Value *D = RHS->getArgOperand(1); 1303 1304 // Look for a common operand. 1305 Value *MinMaxOp = nullptr; 1306 Value *ThirdOp = nullptr; 1307 if (LHS->hasOneUse()) { 1308 // If the LHS is only used in this chain and the RHS is used outside of it, 1309 // reuse the RHS min/max because that will eliminate the LHS. 1310 if (D == A || C == A) { 1311 // min(min(a, b), min(c, a)) --> min(min(c, a), b) 1312 // min(min(a, b), min(a, d)) --> min(min(a, d), b) 1313 MinMaxOp = RHS; 1314 ThirdOp = B; 1315 } else if (D == B || C == B) { 1316 // min(min(a, b), min(c, b)) --> min(min(c, b), a) 1317 // min(min(a, b), min(b, d)) --> min(min(b, d), a) 1318 MinMaxOp = RHS; 1319 ThirdOp = A; 1320 } 1321 } else { 1322 assert(RHS->hasOneUse() && "Expected one-use operand"); 1323 // Reuse the LHS. This will eliminate the RHS. 1324 if (D == A || D == B) { 1325 // min(min(a, b), min(c, a)) --> min(min(a, b), c) 1326 // min(min(a, b), min(c, b)) --> min(min(a, b), c) 1327 MinMaxOp = LHS; 1328 ThirdOp = C; 1329 } else if (C == A || C == B) { 1330 // min(min(a, b), min(b, d)) --> min(min(a, b), d) 1331 // min(min(a, b), min(c, b)) --> min(min(a, b), d) 1332 MinMaxOp = LHS; 1333 ThirdOp = D; 1334 } 1335 } 1336 1337 if (!MinMaxOp || !ThirdOp) 1338 return nullptr; 1339 1340 Module *Mod = II->getModule(); 1341 Function *MinMax = Intrinsic::getDeclaration(Mod, MinMaxID, II->getType()); 1342 return CallInst::Create(MinMax, { MinMaxOp, ThirdOp }); 1343 } 1344 1345 /// If all arguments of the intrinsic are unary shuffles with the same mask, 1346 /// try to shuffle after the intrinsic. 1347 static Instruction * 1348 foldShuffledIntrinsicOperands(IntrinsicInst *II, 1349 InstCombiner::BuilderTy &Builder) { 1350 // TODO: This should be extended to handle other intrinsics like fshl, ctpop, 1351 // etc. Use llvm::isTriviallyVectorizable() and related to determine 1352 // which intrinsics are safe to shuffle? 1353 switch (II->getIntrinsicID()) { 1354 case Intrinsic::smax: 1355 case Intrinsic::smin: 1356 case Intrinsic::umax: 1357 case Intrinsic::umin: 1358 case Intrinsic::fma: 1359 case Intrinsic::fshl: 1360 case Intrinsic::fshr: 1361 break; 1362 default: 1363 return nullptr; 1364 } 1365 1366 Value *X; 1367 ArrayRef<int> Mask; 1368 if (!match(II->getArgOperand(0), 1369 m_Shuffle(m_Value(X), m_Undef(), m_Mask(Mask)))) 1370 return nullptr; 1371 1372 // At least 1 operand must have 1 use because we are creating 2 instructions. 1373 if (none_of(II->args(), [](Value *V) { return V->hasOneUse(); })) 1374 return nullptr; 1375 1376 // See if all arguments are shuffled with the same mask. 1377 SmallVector<Value *, 4> NewArgs(II->arg_size()); 1378 NewArgs[0] = X; 1379 Type *SrcTy = X->getType(); 1380 for (unsigned i = 1, e = II->arg_size(); i != e; ++i) { 1381 if (!match(II->getArgOperand(i), 1382 m_Shuffle(m_Value(X), m_Undef(), m_SpecificMask(Mask))) || 1383 X->getType() != SrcTy) 1384 return nullptr; 1385 NewArgs[i] = X; 1386 } 1387 1388 // intrinsic (shuf X, M), (shuf Y, M), ... --> shuf (intrinsic X, Y, ...), M 1389 Instruction *FPI = isa<FPMathOperator>(II) ? II : nullptr; 1390 Value *NewIntrinsic = 1391 Builder.CreateIntrinsic(II->getIntrinsicID(), SrcTy, NewArgs, FPI); 1392 return new ShuffleVectorInst(NewIntrinsic, Mask); 1393 } 1394 1395 /// Fold the following cases and accepts bswap and bitreverse intrinsics: 1396 /// bswap(logic_op(bswap(x), y)) --> logic_op(x, bswap(y)) 1397 /// bswap(logic_op(bswap(x), bswap(y))) --> logic_op(x, y) (ignores multiuse) 1398 template <Intrinsic::ID IntrID> 1399 static Instruction *foldBitOrderCrossLogicOp(Value *V, 1400 InstCombiner::BuilderTy &Builder) { 1401 static_assert(IntrID == Intrinsic::bswap || IntrID == Intrinsic::bitreverse, 1402 "This helper only supports BSWAP and BITREVERSE intrinsics"); 1403 1404 Value *X, *Y; 1405 // Find bitwise logic op. Check that it is a BinaryOperator explicitly so we 1406 // don't match ConstantExpr that aren't meaningful for this transform. 1407 if (match(V, m_OneUse(m_BitwiseLogic(m_Value(X), m_Value(Y)))) && 1408 isa<BinaryOperator>(V)) { 1409 Value *OldReorderX, *OldReorderY; 1410 BinaryOperator::BinaryOps Op = cast<BinaryOperator>(V)->getOpcode(); 1411 1412 // If both X and Y are bswap/bitreverse, the transform reduces the number 1413 // of instructions even if there's multiuse. 1414 // If only one operand is bswap/bitreverse, we need to ensure the operand 1415 // have only one use. 1416 if (match(X, m_Intrinsic<IntrID>(m_Value(OldReorderX))) && 1417 match(Y, m_Intrinsic<IntrID>(m_Value(OldReorderY)))) { 1418 return BinaryOperator::Create(Op, OldReorderX, OldReorderY); 1419 } 1420 1421 if (match(X, m_OneUse(m_Intrinsic<IntrID>(m_Value(OldReorderX))))) { 1422 Value *NewReorder = Builder.CreateUnaryIntrinsic(IntrID, Y); 1423 return BinaryOperator::Create(Op, OldReorderX, NewReorder); 1424 } 1425 1426 if (match(Y, m_OneUse(m_Intrinsic<IntrID>(m_Value(OldReorderY))))) { 1427 Value *NewReorder = Builder.CreateUnaryIntrinsic(IntrID, X); 1428 return BinaryOperator::Create(Op, NewReorder, OldReorderY); 1429 } 1430 } 1431 return nullptr; 1432 } 1433 1434 static Value *simplifyReductionOperand(Value *Arg, bool CanReorderLanes) { 1435 if (!CanReorderLanes) 1436 return nullptr; 1437 1438 Value *V; 1439 if (match(Arg, m_VecReverse(m_Value(V)))) 1440 return V; 1441 1442 ArrayRef<int> Mask; 1443 if (!isa<FixedVectorType>(Arg->getType()) || 1444 !match(Arg, m_Shuffle(m_Value(V), m_Undef(), m_Mask(Mask))) || 1445 !cast<ShuffleVectorInst>(Arg)->isSingleSource()) 1446 return nullptr; 1447 1448 int Sz = Mask.size(); 1449 SmallBitVector UsedIndices(Sz); 1450 for (int Idx : Mask) { 1451 if (Idx == PoisonMaskElem || UsedIndices.test(Idx)) 1452 return nullptr; 1453 UsedIndices.set(Idx); 1454 } 1455 1456 // Can remove shuffle iff just shuffled elements, no repeats, undefs, or 1457 // other changes. 1458 return UsedIndices.all() ? V : nullptr; 1459 } 1460 1461 /// Fold an unsigned minimum of trailing or leading zero bits counts: 1462 /// umin(cttz(CtOp, ZeroUndef), ConstOp) --> cttz(CtOp | (1 << ConstOp)) 1463 /// umin(ctlz(CtOp, ZeroUndef), ConstOp) --> ctlz(CtOp | (SignedMin 1464 /// >> ConstOp)) 1465 template <Intrinsic::ID IntrID> 1466 static Value * 1467 foldMinimumOverTrailingOrLeadingZeroCount(Value *I0, Value *I1, 1468 const DataLayout &DL, 1469 InstCombiner::BuilderTy &Builder) { 1470 static_assert(IntrID == Intrinsic::cttz || IntrID == Intrinsic::ctlz, 1471 "This helper only supports cttz and ctlz intrinsics"); 1472 1473 Value *CtOp; 1474 Value *ZeroUndef; 1475 if (!match(I0, 1476 m_OneUse(m_Intrinsic<IntrID>(m_Value(CtOp), m_Value(ZeroUndef))))) 1477 return nullptr; 1478 1479 unsigned BitWidth = I1->getType()->getScalarSizeInBits(); 1480 auto LessBitWidth = [BitWidth](auto &C) { return C.ult(BitWidth); }; 1481 if (!match(I1, m_CheckedInt(LessBitWidth))) 1482 // We have a constant >= BitWidth (which can be handled by CVP) 1483 // or a non-splat vector with elements < and >= BitWidth 1484 return nullptr; 1485 1486 Type *Ty = I1->getType(); 1487 Constant *NewConst = ConstantFoldBinaryOpOperands( 1488 IntrID == Intrinsic::cttz ? Instruction::Shl : Instruction::LShr, 1489 IntrID == Intrinsic::cttz 1490 ? ConstantInt::get(Ty, 1) 1491 : ConstantInt::get(Ty, APInt::getSignedMinValue(BitWidth)), 1492 cast<Constant>(I1), DL); 1493 return Builder.CreateBinaryIntrinsic( 1494 IntrID, Builder.CreateOr(CtOp, NewConst), 1495 ConstantInt::getTrue(ZeroUndef->getType())); 1496 } 1497 1498 /// CallInst simplification. This mostly only handles folding of intrinsic 1499 /// instructions. For normal calls, it allows visitCallBase to do the heavy 1500 /// lifting. 1501 Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) { 1502 // Don't try to simplify calls without uses. It will not do anything useful, 1503 // but will result in the following folds being skipped. 1504 if (!CI.use_empty()) { 1505 SmallVector<Value *, 4> Args; 1506 Args.reserve(CI.arg_size()); 1507 for (Value *Op : CI.args()) 1508 Args.push_back(Op); 1509 if (Value *V = simplifyCall(&CI, CI.getCalledOperand(), Args, 1510 SQ.getWithInstruction(&CI))) 1511 return replaceInstUsesWith(CI, V); 1512 } 1513 1514 if (Value *FreedOp = getFreedOperand(&CI, &TLI)) 1515 return visitFree(CI, FreedOp); 1516 1517 // If the caller function (i.e. us, the function that contains this CallInst) 1518 // is nounwind, mark the call as nounwind, even if the callee isn't. 1519 if (CI.getFunction()->doesNotThrow() && !CI.doesNotThrow()) { 1520 CI.setDoesNotThrow(); 1521 return &CI; 1522 } 1523 1524 IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI); 1525 if (!II) return visitCallBase(CI); 1526 1527 // For atomic unordered mem intrinsics if len is not a positive or 1528 // not a multiple of element size then behavior is undefined. 1529 if (auto *AMI = dyn_cast<AtomicMemIntrinsic>(II)) 1530 if (ConstantInt *NumBytes = dyn_cast<ConstantInt>(AMI->getLength())) 1531 if (NumBytes->isNegative() || 1532 (NumBytes->getZExtValue() % AMI->getElementSizeInBytes() != 0)) { 1533 CreateNonTerminatorUnreachable(AMI); 1534 assert(AMI->getType()->isVoidTy() && 1535 "non void atomic unordered mem intrinsic"); 1536 return eraseInstFromFunction(*AMI); 1537 } 1538 1539 // Intrinsics cannot occur in an invoke or a callbr, so handle them here 1540 // instead of in visitCallBase. 1541 if (auto *MI = dyn_cast<AnyMemIntrinsic>(II)) { 1542 bool Changed = false; 1543 1544 // memmove/cpy/set of zero bytes is a noop. 1545 if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) { 1546 if (NumBytes->isNullValue()) 1547 return eraseInstFromFunction(CI); 1548 } 1549 1550 // No other transformations apply to volatile transfers. 1551 if (auto *M = dyn_cast<MemIntrinsic>(MI)) 1552 if (M->isVolatile()) 1553 return nullptr; 1554 1555 // If we have a memmove and the source operation is a constant global, 1556 // then the source and dest pointers can't alias, so we can change this 1557 // into a call to memcpy. 1558 if (auto *MMI = dyn_cast<AnyMemMoveInst>(MI)) { 1559 if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource())) 1560 if (GVSrc->isConstant()) { 1561 Module *M = CI.getModule(); 1562 Intrinsic::ID MemCpyID = 1563 isa<AtomicMemMoveInst>(MMI) 1564 ? Intrinsic::memcpy_element_unordered_atomic 1565 : Intrinsic::memcpy; 1566 Type *Tys[3] = { CI.getArgOperand(0)->getType(), 1567 CI.getArgOperand(1)->getType(), 1568 CI.getArgOperand(2)->getType() }; 1569 CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys)); 1570 Changed = true; 1571 } 1572 } 1573 1574 if (AnyMemTransferInst *MTI = dyn_cast<AnyMemTransferInst>(MI)) { 1575 // memmove(x,x,size) -> noop. 1576 if (MTI->getSource() == MTI->getDest()) 1577 return eraseInstFromFunction(CI); 1578 } 1579 1580 // If we can determine a pointer alignment that is bigger than currently 1581 // set, update the alignment. 1582 if (auto *MTI = dyn_cast<AnyMemTransferInst>(MI)) { 1583 if (Instruction *I = SimplifyAnyMemTransfer(MTI)) 1584 return I; 1585 } else if (auto *MSI = dyn_cast<AnyMemSetInst>(MI)) { 1586 if (Instruction *I = SimplifyAnyMemSet(MSI)) 1587 return I; 1588 } 1589 1590 if (Changed) return II; 1591 } 1592 1593 // For fixed width vector result intrinsics, use the generic demanded vector 1594 // support. 1595 if (auto *IIFVTy = dyn_cast<FixedVectorType>(II->getType())) { 1596 auto VWidth = IIFVTy->getNumElements(); 1597 APInt PoisonElts(VWidth, 0); 1598 APInt AllOnesEltMask(APInt::getAllOnes(VWidth)); 1599 if (Value *V = SimplifyDemandedVectorElts(II, AllOnesEltMask, PoisonElts)) { 1600 if (V != II) 1601 return replaceInstUsesWith(*II, V); 1602 return II; 1603 } 1604 } 1605 1606 if (II->isCommutative()) { 1607 if (auto Pair = matchSymmetricPair(II->getOperand(0), II->getOperand(1))) { 1608 replaceOperand(*II, 0, Pair->first); 1609 replaceOperand(*II, 1, Pair->second); 1610 return II; 1611 } 1612 1613 if (CallInst *NewCall = canonicalizeConstantArg0ToArg1(CI)) 1614 return NewCall; 1615 } 1616 1617 // Unused constrained FP intrinsic calls may have declared side effect, which 1618 // prevents it from being removed. In some cases however the side effect is 1619 // actually absent. To detect this case, call SimplifyConstrainedFPCall. If it 1620 // returns a replacement, the call may be removed. 1621 if (CI.use_empty() && isa<ConstrainedFPIntrinsic>(CI)) { 1622 if (simplifyConstrainedFPCall(&CI, SQ.getWithInstruction(&CI))) 1623 return eraseInstFromFunction(CI); 1624 } 1625 1626 Intrinsic::ID IID = II->getIntrinsicID(); 1627 switch (IID) { 1628 case Intrinsic::objectsize: { 1629 SmallVector<Instruction *> InsertedInstructions; 1630 if (Value *V = lowerObjectSizeCall(II, DL, &TLI, AA, /*MustSucceed=*/false, 1631 &InsertedInstructions)) { 1632 for (Instruction *Inserted : InsertedInstructions) 1633 Worklist.add(Inserted); 1634 return replaceInstUsesWith(CI, V); 1635 } 1636 return nullptr; 1637 } 1638 case Intrinsic::abs: { 1639 Value *IIOperand = II->getArgOperand(0); 1640 bool IntMinIsPoison = cast<Constant>(II->getArgOperand(1))->isOneValue(); 1641 1642 // abs(-x) -> abs(x) 1643 // TODO: Copy nsw if it was present on the neg? 1644 Value *X; 1645 if (match(IIOperand, m_Neg(m_Value(X)))) 1646 return replaceOperand(*II, 0, X); 1647 if (match(IIOperand, m_Select(m_Value(), m_Value(X), m_Neg(m_Deferred(X))))) 1648 return replaceOperand(*II, 0, X); 1649 if (match(IIOperand, m_Select(m_Value(), m_Neg(m_Value(X)), m_Deferred(X)))) 1650 return replaceOperand(*II, 0, X); 1651 1652 Value *Y; 1653 // abs(a * abs(b)) -> abs(a * b) 1654 if (match(IIOperand, 1655 m_OneUse(m_c_Mul(m_Value(X), 1656 m_Intrinsic<Intrinsic::abs>(m_Value(Y)))))) { 1657 bool NSW = 1658 cast<Instruction>(IIOperand)->hasNoSignedWrap() && IntMinIsPoison; 1659 auto *XY = NSW ? Builder.CreateNSWMul(X, Y) : Builder.CreateMul(X, Y); 1660 return replaceOperand(*II, 0, XY); 1661 } 1662 1663 if (std::optional<bool> Known = 1664 getKnownSignOrZero(IIOperand, SQ.getWithInstruction(II))) { 1665 // abs(x) -> x if x >= 0 (include abs(x-y) --> x - y where x >= y) 1666 // abs(x) -> x if x > 0 (include abs(x-y) --> x - y where x > y) 1667 if (!*Known) 1668 return replaceInstUsesWith(*II, IIOperand); 1669 1670 // abs(x) -> -x if x < 0 1671 // abs(x) -> -x if x < = 0 (include abs(x-y) --> y - x where x <= y) 1672 if (IntMinIsPoison) 1673 return BinaryOperator::CreateNSWNeg(IIOperand); 1674 return BinaryOperator::CreateNeg(IIOperand); 1675 } 1676 1677 // abs (sext X) --> zext (abs X*) 1678 // Clear the IsIntMin (nsw) bit on the abs to allow narrowing. 1679 if (match(IIOperand, m_OneUse(m_SExt(m_Value(X))))) { 1680 Value *NarrowAbs = 1681 Builder.CreateBinaryIntrinsic(Intrinsic::abs, X, Builder.getFalse()); 1682 return CastInst::Create(Instruction::ZExt, NarrowAbs, II->getType()); 1683 } 1684 1685 // Match a complicated way to check if a number is odd/even: 1686 // abs (srem X, 2) --> and X, 1 1687 const APInt *C; 1688 if (match(IIOperand, m_SRem(m_Value(X), m_APInt(C))) && *C == 2) 1689 return BinaryOperator::CreateAnd(X, ConstantInt::get(II->getType(), 1)); 1690 1691 break; 1692 } 1693 case Intrinsic::umin: { 1694 Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); 1695 // umin(x, 1) == zext(x != 0) 1696 if (match(I1, m_One())) { 1697 assert(II->getType()->getScalarSizeInBits() != 1 && 1698 "Expected simplify of umin with max constant"); 1699 Value *Zero = Constant::getNullValue(I0->getType()); 1700 Value *Cmp = Builder.CreateICmpNE(I0, Zero); 1701 return CastInst::Create(Instruction::ZExt, Cmp, II->getType()); 1702 } 1703 // umin(cttz(x), const) --> cttz(x | (1 << const)) 1704 if (Value *FoldedCttz = 1705 foldMinimumOverTrailingOrLeadingZeroCount<Intrinsic::cttz>( 1706 I0, I1, DL, Builder)) 1707 return replaceInstUsesWith(*II, FoldedCttz); 1708 // umin(ctlz(x), const) --> ctlz(x | (SignedMin >> const)) 1709 if (Value *FoldedCtlz = 1710 foldMinimumOverTrailingOrLeadingZeroCount<Intrinsic::ctlz>( 1711 I0, I1, DL, Builder)) 1712 return replaceInstUsesWith(*II, FoldedCtlz); 1713 [[fallthrough]]; 1714 } 1715 case Intrinsic::umax: { 1716 Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); 1717 Value *X, *Y; 1718 if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_ZExt(m_Value(Y))) && 1719 (I0->hasOneUse() || I1->hasOneUse()) && X->getType() == Y->getType()) { 1720 Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, Y); 1721 return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType()); 1722 } 1723 Constant *C; 1724 if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_Constant(C)) && 1725 I0->hasOneUse()) { 1726 if (Constant *NarrowC = getLosslessUnsignedTrunc(C, X->getType())) { 1727 Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC); 1728 return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType()); 1729 } 1730 } 1731 // If both operands of unsigned min/max are sign-extended, it is still ok 1732 // to narrow the operation. 1733 [[fallthrough]]; 1734 } 1735 case Intrinsic::smax: 1736 case Intrinsic::smin: { 1737 Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); 1738 Value *X, *Y; 1739 if (match(I0, m_SExt(m_Value(X))) && match(I1, m_SExt(m_Value(Y))) && 1740 (I0->hasOneUse() || I1->hasOneUse()) && X->getType() == Y->getType()) { 1741 Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, Y); 1742 return CastInst::Create(Instruction::SExt, NarrowMaxMin, II->getType()); 1743 } 1744 1745 Constant *C; 1746 if (match(I0, m_SExt(m_Value(X))) && match(I1, m_Constant(C)) && 1747 I0->hasOneUse()) { 1748 if (Constant *NarrowC = getLosslessSignedTrunc(C, X->getType())) { 1749 Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC); 1750 return CastInst::Create(Instruction::SExt, NarrowMaxMin, II->getType()); 1751 } 1752 } 1753 1754 // umin(i1 X, i1 Y) -> and i1 X, Y 1755 // smax(i1 X, i1 Y) -> and i1 X, Y 1756 if ((IID == Intrinsic::umin || IID == Intrinsic::smax) && 1757 II->getType()->isIntOrIntVectorTy(1)) { 1758 return BinaryOperator::CreateAnd(I0, I1); 1759 } 1760 1761 // umax(i1 X, i1 Y) -> or i1 X, Y 1762 // smin(i1 X, i1 Y) -> or i1 X, Y 1763 if ((IID == Intrinsic::umax || IID == Intrinsic::smin) && 1764 II->getType()->isIntOrIntVectorTy(1)) { 1765 return BinaryOperator::CreateOr(I0, I1); 1766 } 1767 1768 if (IID == Intrinsic::smax || IID == Intrinsic::smin) { 1769 // smax (neg nsw X), (neg nsw Y) --> neg nsw (smin X, Y) 1770 // smin (neg nsw X), (neg nsw Y) --> neg nsw (smax X, Y) 1771 // TODO: Canonicalize neg after min/max if I1 is constant. 1772 if (match(I0, m_NSWNeg(m_Value(X))) && match(I1, m_NSWNeg(m_Value(Y))) && 1773 (I0->hasOneUse() || I1->hasOneUse())) { 1774 Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID); 1775 Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, Y); 1776 return BinaryOperator::CreateNSWNeg(InvMaxMin); 1777 } 1778 } 1779 1780 // (umax X, (xor X, Pow2)) 1781 // -> (or X, Pow2) 1782 // (umin X, (xor X, Pow2)) 1783 // -> (and X, ~Pow2) 1784 // (smax X, (xor X, Pos_Pow2)) 1785 // -> (or X, Pos_Pow2) 1786 // (smin X, (xor X, Pos_Pow2)) 1787 // -> (and X, ~Pos_Pow2) 1788 // (smax X, (xor X, Neg_Pow2)) 1789 // -> (and X, ~Neg_Pow2) 1790 // (smin X, (xor X, Neg_Pow2)) 1791 // -> (or X, Neg_Pow2) 1792 if ((match(I0, m_c_Xor(m_Specific(I1), m_Value(X))) || 1793 match(I1, m_c_Xor(m_Specific(I0), m_Value(X)))) && 1794 isKnownToBeAPowerOfTwo(X, /* OrZero */ true)) { 1795 bool UseOr = IID == Intrinsic::smax || IID == Intrinsic::umax; 1796 bool UseAndN = IID == Intrinsic::smin || IID == Intrinsic::umin; 1797 1798 if (IID == Intrinsic::smax || IID == Intrinsic::smin) { 1799 auto KnownSign = getKnownSign(X, SQ.getWithInstruction(II)); 1800 if (KnownSign == std::nullopt) { 1801 UseOr = false; 1802 UseAndN = false; 1803 } else if (*KnownSign /* true is Signed. */) { 1804 UseOr ^= true; 1805 UseAndN ^= true; 1806 Type *Ty = I0->getType(); 1807 // Negative power of 2 must be IntMin. It's possible to be able to 1808 // prove negative / power of 2 without actually having known bits, so 1809 // just get the value by hand. 1810 X = Constant::getIntegerValue( 1811 Ty, APInt::getSignedMinValue(Ty->getScalarSizeInBits())); 1812 } 1813 } 1814 if (UseOr) 1815 return BinaryOperator::CreateOr(I0, X); 1816 else if (UseAndN) 1817 return BinaryOperator::CreateAnd(I0, Builder.CreateNot(X)); 1818 } 1819 1820 // If we can eliminate ~A and Y is free to invert: 1821 // max ~A, Y --> ~(min A, ~Y) 1822 // 1823 // Examples: 1824 // max ~A, ~Y --> ~(min A, Y) 1825 // max ~A, C --> ~(min A, ~C) 1826 // max ~A, (max ~Y, ~Z) --> ~min( A, (min Y, Z)) 1827 auto moveNotAfterMinMax = [&](Value *X, Value *Y) -> Instruction * { 1828 Value *A; 1829 if (match(X, m_OneUse(m_Not(m_Value(A)))) && 1830 !isFreeToInvert(A, A->hasOneUse())) { 1831 if (Value *NotY = getFreelyInverted(Y, Y->hasOneUse(), &Builder)) { 1832 Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID); 1833 Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, A, NotY); 1834 return BinaryOperator::CreateNot(InvMaxMin); 1835 } 1836 } 1837 return nullptr; 1838 }; 1839 1840 if (Instruction *I = moveNotAfterMinMax(I0, I1)) 1841 return I; 1842 if (Instruction *I = moveNotAfterMinMax(I1, I0)) 1843 return I; 1844 1845 if (Instruction *I = moveAddAfterMinMax(II, Builder)) 1846 return I; 1847 1848 // minmax (X & NegPow2C, Y & NegPow2C) --> minmax(X, Y) & NegPow2C 1849 const APInt *RHSC; 1850 if (match(I0, m_OneUse(m_And(m_Value(X), m_NegatedPower2(RHSC)))) && 1851 match(I1, m_OneUse(m_And(m_Value(Y), m_SpecificInt(*RHSC))))) 1852 return BinaryOperator::CreateAnd(Builder.CreateBinaryIntrinsic(IID, X, Y), 1853 ConstantInt::get(II->getType(), *RHSC)); 1854 1855 // smax(X, -X) --> abs(X) 1856 // smin(X, -X) --> -abs(X) 1857 // umax(X, -X) --> -abs(X) 1858 // umin(X, -X) --> abs(X) 1859 if (isKnownNegation(I0, I1)) { 1860 // We can choose either operand as the input to abs(), but if we can 1861 // eliminate the only use of a value, that's better for subsequent 1862 // transforms/analysis. 1863 if (I0->hasOneUse() && !I1->hasOneUse()) 1864 std::swap(I0, I1); 1865 1866 // This is some variant of abs(). See if we can propagate 'nsw' to the abs 1867 // operation and potentially its negation. 1868 bool IntMinIsPoison = isKnownNegation(I0, I1, /* NeedNSW */ true); 1869 Value *Abs = Builder.CreateBinaryIntrinsic( 1870 Intrinsic::abs, I0, 1871 ConstantInt::getBool(II->getContext(), IntMinIsPoison)); 1872 1873 // We don't have a "nabs" intrinsic, so negate if needed based on the 1874 // max/min operation. 1875 if (IID == Intrinsic::smin || IID == Intrinsic::umax) 1876 Abs = Builder.CreateNeg(Abs, "nabs", IntMinIsPoison); 1877 return replaceInstUsesWith(CI, Abs); 1878 } 1879 1880 if (Instruction *Sel = foldClampRangeOfTwo(II, Builder)) 1881 return Sel; 1882 1883 if (Instruction *SAdd = matchSAddSubSat(*II)) 1884 return SAdd; 1885 1886 if (Value *NewMinMax = reassociateMinMaxWithConstants(II, Builder, SQ)) 1887 return replaceInstUsesWith(*II, NewMinMax); 1888 1889 if (Instruction *R = reassociateMinMaxWithConstantInOperand(II, Builder)) 1890 return R; 1891 1892 if (Instruction *NewMinMax = factorizeMinMaxTree(II)) 1893 return NewMinMax; 1894 1895 // Try to fold minmax with constant RHS based on range information 1896 if (match(I1, m_APIntAllowPoison(RHSC))) { 1897 ICmpInst::Predicate Pred = 1898 ICmpInst::getNonStrictPredicate(MinMaxIntrinsic::getPredicate(IID)); 1899 bool IsSigned = MinMaxIntrinsic::isSigned(IID); 1900 ConstantRange LHS_CR = computeConstantRangeIncludingKnownBits( 1901 I0, IsSigned, SQ.getWithInstruction(II)); 1902 if (!LHS_CR.isFullSet()) { 1903 if (LHS_CR.icmp(Pred, *RHSC)) 1904 return replaceInstUsesWith(*II, I0); 1905 if (LHS_CR.icmp(ICmpInst::getSwappedPredicate(Pred), *RHSC)) 1906 return replaceInstUsesWith(*II, 1907 ConstantInt::get(II->getType(), *RHSC)); 1908 } 1909 } 1910 1911 break; 1912 } 1913 case Intrinsic::bitreverse: { 1914 Value *IIOperand = II->getArgOperand(0); 1915 // bitrev (zext i1 X to ?) --> X ? SignBitC : 0 1916 Value *X; 1917 if (match(IIOperand, m_ZExt(m_Value(X))) && 1918 X->getType()->isIntOrIntVectorTy(1)) { 1919 Type *Ty = II->getType(); 1920 APInt SignBit = APInt::getSignMask(Ty->getScalarSizeInBits()); 1921 return SelectInst::Create(X, ConstantInt::get(Ty, SignBit), 1922 ConstantInt::getNullValue(Ty)); 1923 } 1924 1925 if (Instruction *crossLogicOpFold = 1926 foldBitOrderCrossLogicOp<Intrinsic::bitreverse>(IIOperand, Builder)) 1927 return crossLogicOpFold; 1928 1929 break; 1930 } 1931 case Intrinsic::bswap: { 1932 Value *IIOperand = II->getArgOperand(0); 1933 1934 // Try to canonicalize bswap-of-logical-shift-by-8-bit-multiple as 1935 // inverse-shift-of-bswap: 1936 // bswap (shl X, Y) --> lshr (bswap X), Y 1937 // bswap (lshr X, Y) --> shl (bswap X), Y 1938 Value *X, *Y; 1939 if (match(IIOperand, m_OneUse(m_LogicalShift(m_Value(X), m_Value(Y))))) { 1940 unsigned BitWidth = IIOperand->getType()->getScalarSizeInBits(); 1941 if (MaskedValueIsZero(Y, APInt::getLowBitsSet(BitWidth, 3))) { 1942 Value *NewSwap = Builder.CreateUnaryIntrinsic(Intrinsic::bswap, X); 1943 BinaryOperator::BinaryOps InverseShift = 1944 cast<BinaryOperator>(IIOperand)->getOpcode() == Instruction::Shl 1945 ? Instruction::LShr 1946 : Instruction::Shl; 1947 return BinaryOperator::Create(InverseShift, NewSwap, Y); 1948 } 1949 } 1950 1951 KnownBits Known = computeKnownBits(IIOperand, 0, II); 1952 uint64_t LZ = alignDown(Known.countMinLeadingZeros(), 8); 1953 uint64_t TZ = alignDown(Known.countMinTrailingZeros(), 8); 1954 unsigned BW = Known.getBitWidth(); 1955 1956 // bswap(x) -> shift(x) if x has exactly one "active byte" 1957 if (BW - LZ - TZ == 8) { 1958 assert(LZ != TZ && "active byte cannot be in the middle"); 1959 if (LZ > TZ) // -> shl(x) if the "active byte" is in the low part of x 1960 return BinaryOperator::CreateNUWShl( 1961 IIOperand, ConstantInt::get(IIOperand->getType(), LZ - TZ)); 1962 // -> lshr(x) if the "active byte" is in the high part of x 1963 return BinaryOperator::CreateExactLShr( 1964 IIOperand, ConstantInt::get(IIOperand->getType(), TZ - LZ)); 1965 } 1966 1967 // bswap(trunc(bswap(x))) -> trunc(lshr(x, c)) 1968 if (match(IIOperand, m_Trunc(m_BSwap(m_Value(X))))) { 1969 unsigned C = X->getType()->getScalarSizeInBits() - BW; 1970 Value *CV = ConstantInt::get(X->getType(), C); 1971 Value *V = Builder.CreateLShr(X, CV); 1972 return new TruncInst(V, IIOperand->getType()); 1973 } 1974 1975 if (Instruction *crossLogicOpFold = 1976 foldBitOrderCrossLogicOp<Intrinsic::bswap>(IIOperand, Builder)) { 1977 return crossLogicOpFold; 1978 } 1979 1980 // Try to fold into bitreverse if bswap is the root of the expression tree. 1981 if (Instruction *BitOp = matchBSwapOrBitReverse(*II, /*MatchBSwaps*/ false, 1982 /*MatchBitReversals*/ true)) 1983 return BitOp; 1984 break; 1985 } 1986 case Intrinsic::masked_load: 1987 if (Value *SimplifiedMaskedOp = simplifyMaskedLoad(*II)) 1988 return replaceInstUsesWith(CI, SimplifiedMaskedOp); 1989 break; 1990 case Intrinsic::masked_store: 1991 return simplifyMaskedStore(*II); 1992 case Intrinsic::masked_gather: 1993 return simplifyMaskedGather(*II); 1994 case Intrinsic::masked_scatter: 1995 return simplifyMaskedScatter(*II); 1996 case Intrinsic::launder_invariant_group: 1997 case Intrinsic::strip_invariant_group: 1998 if (auto *SkippedBarrier = simplifyInvariantGroupIntrinsic(*II, *this)) 1999 return replaceInstUsesWith(*II, SkippedBarrier); 2000 break; 2001 case Intrinsic::powi: 2002 if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 2003 // 0 and 1 are handled in instsimplify 2004 // powi(x, -1) -> 1/x 2005 if (Power->isMinusOne()) 2006 return BinaryOperator::CreateFDivFMF(ConstantFP::get(CI.getType(), 1.0), 2007 II->getArgOperand(0), II); 2008 // powi(x, 2) -> x*x 2009 if (Power->equalsInt(2)) 2010 return BinaryOperator::CreateFMulFMF(II->getArgOperand(0), 2011 II->getArgOperand(0), II); 2012 2013 if (!Power->getValue()[0]) { 2014 Value *X; 2015 // If power is even: 2016 // powi(-x, p) -> powi(x, p) 2017 // powi(fabs(x), p) -> powi(x, p) 2018 // powi(copysign(x, y), p) -> powi(x, p) 2019 if (match(II->getArgOperand(0), m_FNeg(m_Value(X))) || 2020 match(II->getArgOperand(0), m_FAbs(m_Value(X))) || 2021 match(II->getArgOperand(0), 2022 m_Intrinsic<Intrinsic::copysign>(m_Value(X), m_Value()))) 2023 return replaceOperand(*II, 0, X); 2024 } 2025 } 2026 break; 2027 2028 case Intrinsic::cttz: 2029 case Intrinsic::ctlz: 2030 if (auto *I = foldCttzCtlz(*II, *this)) 2031 return I; 2032 break; 2033 2034 case Intrinsic::ctpop: 2035 if (auto *I = foldCtpop(*II, *this)) 2036 return I; 2037 break; 2038 2039 case Intrinsic::fshl: 2040 case Intrinsic::fshr: { 2041 Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1); 2042 Type *Ty = II->getType(); 2043 unsigned BitWidth = Ty->getScalarSizeInBits(); 2044 Constant *ShAmtC; 2045 if (match(II->getArgOperand(2), m_ImmConstant(ShAmtC))) { 2046 // Canonicalize a shift amount constant operand to modulo the bit-width. 2047 Constant *WidthC = ConstantInt::get(Ty, BitWidth); 2048 Constant *ModuloC = 2049 ConstantFoldBinaryOpOperands(Instruction::URem, ShAmtC, WidthC, DL); 2050 if (!ModuloC) 2051 return nullptr; 2052 if (ModuloC != ShAmtC) 2053 return replaceOperand(*II, 2, ModuloC); 2054 2055 assert(match(ConstantFoldCompareInstOperands(ICmpInst::ICMP_UGT, WidthC, 2056 ShAmtC, DL), 2057 m_One()) && 2058 "Shift amount expected to be modulo bitwidth"); 2059 2060 // Canonicalize funnel shift right by constant to funnel shift left. This 2061 // is not entirely arbitrary. For historical reasons, the backend may 2062 // recognize rotate left patterns but miss rotate right patterns. 2063 if (IID == Intrinsic::fshr) { 2064 // fshr X, Y, C --> fshl X, Y, (BitWidth - C) if C is not zero. 2065 if (!isKnownNonZero(ShAmtC, SQ.getWithInstruction(II))) 2066 return nullptr; 2067 2068 Constant *LeftShiftC = ConstantExpr::getSub(WidthC, ShAmtC); 2069 Module *Mod = II->getModule(); 2070 Function *Fshl = Intrinsic::getDeclaration(Mod, Intrinsic::fshl, Ty); 2071 return CallInst::Create(Fshl, { Op0, Op1, LeftShiftC }); 2072 } 2073 assert(IID == Intrinsic::fshl && 2074 "All funnel shifts by simple constants should go left"); 2075 2076 // fshl(X, 0, C) --> shl X, C 2077 // fshl(X, undef, C) --> shl X, C 2078 if (match(Op1, m_ZeroInt()) || match(Op1, m_Undef())) 2079 return BinaryOperator::CreateShl(Op0, ShAmtC); 2080 2081 // fshl(0, X, C) --> lshr X, (BW-C) 2082 // fshl(undef, X, C) --> lshr X, (BW-C) 2083 if (match(Op0, m_ZeroInt()) || match(Op0, m_Undef())) 2084 return BinaryOperator::CreateLShr(Op1, 2085 ConstantExpr::getSub(WidthC, ShAmtC)); 2086 2087 // fshl i16 X, X, 8 --> bswap i16 X (reduce to more-specific form) 2088 if (Op0 == Op1 && BitWidth == 16 && match(ShAmtC, m_SpecificInt(8))) { 2089 Module *Mod = II->getModule(); 2090 Function *Bswap = Intrinsic::getDeclaration(Mod, Intrinsic::bswap, Ty); 2091 return CallInst::Create(Bswap, { Op0 }); 2092 } 2093 if (Instruction *BitOp = 2094 matchBSwapOrBitReverse(*II, /*MatchBSwaps*/ true, 2095 /*MatchBitReversals*/ true)) 2096 return BitOp; 2097 } 2098 2099 // Left or right might be masked. 2100 if (SimplifyDemandedInstructionBits(*II)) 2101 return &CI; 2102 2103 // The shift amount (operand 2) of a funnel shift is modulo the bitwidth, 2104 // so only the low bits of the shift amount are demanded if the bitwidth is 2105 // a power-of-2. 2106 if (!isPowerOf2_32(BitWidth)) 2107 break; 2108 APInt Op2Demanded = APInt::getLowBitsSet(BitWidth, Log2_32_Ceil(BitWidth)); 2109 KnownBits Op2Known(BitWidth); 2110 if (SimplifyDemandedBits(II, 2, Op2Demanded, Op2Known)) 2111 return &CI; 2112 break; 2113 } 2114 case Intrinsic::ptrmask: { 2115 unsigned BitWidth = DL.getPointerTypeSizeInBits(II->getType()); 2116 KnownBits Known(BitWidth); 2117 if (SimplifyDemandedInstructionBits(*II, Known)) 2118 return II; 2119 2120 Value *InnerPtr, *InnerMask; 2121 bool Changed = false; 2122 // Combine: 2123 // (ptrmask (ptrmask p, A), B) 2124 // -> (ptrmask p, (and A, B)) 2125 if (match(II->getArgOperand(0), 2126 m_OneUse(m_Intrinsic<Intrinsic::ptrmask>(m_Value(InnerPtr), 2127 m_Value(InnerMask))))) { 2128 assert(II->getArgOperand(1)->getType() == InnerMask->getType() && 2129 "Mask types must match"); 2130 // TODO: If InnerMask == Op1, we could copy attributes from inner 2131 // callsite -> outer callsite. 2132 Value *NewMask = Builder.CreateAnd(II->getArgOperand(1), InnerMask); 2133 replaceOperand(CI, 0, InnerPtr); 2134 replaceOperand(CI, 1, NewMask); 2135 Changed = true; 2136 } 2137 2138 // See if we can deduce non-null. 2139 if (!CI.hasRetAttr(Attribute::NonNull) && 2140 (Known.isNonZero() || 2141 isKnownNonZero(II, getSimplifyQuery().getWithInstruction(II)))) { 2142 CI.addRetAttr(Attribute::NonNull); 2143 Changed = true; 2144 } 2145 2146 unsigned NewAlignmentLog = 2147 std::min(Value::MaxAlignmentExponent, 2148 std::min(BitWidth - 1, Known.countMinTrailingZeros())); 2149 // Known bits will capture if we had alignment information associated with 2150 // the pointer argument. 2151 if (NewAlignmentLog > Log2(CI.getRetAlign().valueOrOne())) { 2152 CI.addRetAttr(Attribute::getWithAlignment( 2153 CI.getContext(), Align(uint64_t(1) << NewAlignmentLog))); 2154 Changed = true; 2155 } 2156 if (Changed) 2157 return &CI; 2158 break; 2159 } 2160 case Intrinsic::uadd_with_overflow: 2161 case Intrinsic::sadd_with_overflow: { 2162 if (Instruction *I = foldIntrinsicWithOverflowCommon(II)) 2163 return I; 2164 2165 // Given 2 constant operands whose sum does not overflow: 2166 // uaddo (X +nuw C0), C1 -> uaddo X, C0 + C1 2167 // saddo (X +nsw C0), C1 -> saddo X, C0 + C1 2168 Value *X; 2169 const APInt *C0, *C1; 2170 Value *Arg0 = II->getArgOperand(0); 2171 Value *Arg1 = II->getArgOperand(1); 2172 bool IsSigned = IID == Intrinsic::sadd_with_overflow; 2173 bool HasNWAdd = IsSigned 2174 ? match(Arg0, m_NSWAddLike(m_Value(X), m_APInt(C0))) 2175 : match(Arg0, m_NUWAddLike(m_Value(X), m_APInt(C0))); 2176 if (HasNWAdd && match(Arg1, m_APInt(C1))) { 2177 bool Overflow; 2178 APInt NewC = 2179 IsSigned ? C1->sadd_ov(*C0, Overflow) : C1->uadd_ov(*C0, Overflow); 2180 if (!Overflow) 2181 return replaceInstUsesWith( 2182 *II, Builder.CreateBinaryIntrinsic( 2183 IID, X, ConstantInt::get(Arg1->getType(), NewC))); 2184 } 2185 break; 2186 } 2187 2188 case Intrinsic::umul_with_overflow: 2189 case Intrinsic::smul_with_overflow: 2190 case Intrinsic::usub_with_overflow: 2191 if (Instruction *I = foldIntrinsicWithOverflowCommon(II)) 2192 return I; 2193 break; 2194 2195 case Intrinsic::ssub_with_overflow: { 2196 if (Instruction *I = foldIntrinsicWithOverflowCommon(II)) 2197 return I; 2198 2199 Constant *C; 2200 Value *Arg0 = II->getArgOperand(0); 2201 Value *Arg1 = II->getArgOperand(1); 2202 // Given a constant C that is not the minimum signed value 2203 // for an integer of a given bit width: 2204 // 2205 // ssubo X, C -> saddo X, -C 2206 if (match(Arg1, m_Constant(C)) && C->isNotMinSignedValue()) { 2207 Value *NegVal = ConstantExpr::getNeg(C); 2208 // Build a saddo call that is equivalent to the discovered 2209 // ssubo call. 2210 return replaceInstUsesWith( 2211 *II, Builder.CreateBinaryIntrinsic(Intrinsic::sadd_with_overflow, 2212 Arg0, NegVal)); 2213 } 2214 2215 break; 2216 } 2217 2218 case Intrinsic::uadd_sat: 2219 case Intrinsic::sadd_sat: 2220 case Intrinsic::usub_sat: 2221 case Intrinsic::ssub_sat: { 2222 SaturatingInst *SI = cast<SaturatingInst>(II); 2223 Type *Ty = SI->getType(); 2224 Value *Arg0 = SI->getLHS(); 2225 Value *Arg1 = SI->getRHS(); 2226 2227 // Make use of known overflow information. 2228 OverflowResult OR = computeOverflow(SI->getBinaryOp(), SI->isSigned(), 2229 Arg0, Arg1, SI); 2230 switch (OR) { 2231 case OverflowResult::MayOverflow: 2232 break; 2233 case OverflowResult::NeverOverflows: 2234 if (SI->isSigned()) 2235 return BinaryOperator::CreateNSW(SI->getBinaryOp(), Arg0, Arg1); 2236 else 2237 return BinaryOperator::CreateNUW(SI->getBinaryOp(), Arg0, Arg1); 2238 case OverflowResult::AlwaysOverflowsLow: { 2239 unsigned BitWidth = Ty->getScalarSizeInBits(); 2240 APInt Min = APSInt::getMinValue(BitWidth, !SI->isSigned()); 2241 return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Min)); 2242 } 2243 case OverflowResult::AlwaysOverflowsHigh: { 2244 unsigned BitWidth = Ty->getScalarSizeInBits(); 2245 APInt Max = APSInt::getMaxValue(BitWidth, !SI->isSigned()); 2246 return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Max)); 2247 } 2248 } 2249 2250 // usub_sat((sub nuw C, A), C1) -> usub_sat(usub_sat(C, C1), A) 2251 // which after that: 2252 // usub_sat((sub nuw C, A), C1) -> usub_sat(C - C1, A) if C1 u< C 2253 // usub_sat((sub nuw C, A), C1) -> 0 otherwise 2254 Constant *C, *C1; 2255 Value *A; 2256 if (IID == Intrinsic::usub_sat && 2257 match(Arg0, m_NUWSub(m_ImmConstant(C), m_Value(A))) && 2258 match(Arg1, m_ImmConstant(C1))) { 2259 auto *NewC = Builder.CreateBinaryIntrinsic(Intrinsic::usub_sat, C, C1); 2260 auto *NewSub = 2261 Builder.CreateBinaryIntrinsic(Intrinsic::usub_sat, NewC, A); 2262 return replaceInstUsesWith(*SI, NewSub); 2263 } 2264 2265 // ssub.sat(X, C) -> sadd.sat(X, -C) if C != MIN 2266 if (IID == Intrinsic::ssub_sat && match(Arg1, m_Constant(C)) && 2267 C->isNotMinSignedValue()) { 2268 Value *NegVal = ConstantExpr::getNeg(C); 2269 return replaceInstUsesWith( 2270 *II, Builder.CreateBinaryIntrinsic( 2271 Intrinsic::sadd_sat, Arg0, NegVal)); 2272 } 2273 2274 // sat(sat(X + Val2) + Val) -> sat(X + (Val+Val2)) 2275 // sat(sat(X - Val2) - Val) -> sat(X - (Val+Val2)) 2276 // if Val and Val2 have the same sign 2277 if (auto *Other = dyn_cast<IntrinsicInst>(Arg0)) { 2278 Value *X; 2279 const APInt *Val, *Val2; 2280 APInt NewVal; 2281 bool IsUnsigned = 2282 IID == Intrinsic::uadd_sat || IID == Intrinsic::usub_sat; 2283 if (Other->getIntrinsicID() == IID && 2284 match(Arg1, m_APInt(Val)) && 2285 match(Other->getArgOperand(0), m_Value(X)) && 2286 match(Other->getArgOperand(1), m_APInt(Val2))) { 2287 if (IsUnsigned) 2288 NewVal = Val->uadd_sat(*Val2); 2289 else if (Val->isNonNegative() == Val2->isNonNegative()) { 2290 bool Overflow; 2291 NewVal = Val->sadd_ov(*Val2, Overflow); 2292 if (Overflow) { 2293 // Both adds together may add more than SignedMaxValue 2294 // without saturating the final result. 2295 break; 2296 } 2297 } else { 2298 // Cannot fold saturated addition with different signs. 2299 break; 2300 } 2301 2302 return replaceInstUsesWith( 2303 *II, Builder.CreateBinaryIntrinsic( 2304 IID, X, ConstantInt::get(II->getType(), NewVal))); 2305 } 2306 } 2307 break; 2308 } 2309 2310 case Intrinsic::minnum: 2311 case Intrinsic::maxnum: 2312 case Intrinsic::minimum: 2313 case Intrinsic::maximum: { 2314 Value *Arg0 = II->getArgOperand(0); 2315 Value *Arg1 = II->getArgOperand(1); 2316 Value *X, *Y; 2317 if (match(Arg0, m_FNeg(m_Value(X))) && match(Arg1, m_FNeg(m_Value(Y))) && 2318 (Arg0->hasOneUse() || Arg1->hasOneUse())) { 2319 // If both operands are negated, invert the call and negate the result: 2320 // min(-X, -Y) --> -(max(X, Y)) 2321 // max(-X, -Y) --> -(min(X, Y)) 2322 Intrinsic::ID NewIID; 2323 switch (IID) { 2324 case Intrinsic::maxnum: 2325 NewIID = Intrinsic::minnum; 2326 break; 2327 case Intrinsic::minnum: 2328 NewIID = Intrinsic::maxnum; 2329 break; 2330 case Intrinsic::maximum: 2331 NewIID = Intrinsic::minimum; 2332 break; 2333 case Intrinsic::minimum: 2334 NewIID = Intrinsic::maximum; 2335 break; 2336 default: 2337 llvm_unreachable("unexpected intrinsic ID"); 2338 } 2339 Value *NewCall = Builder.CreateBinaryIntrinsic(NewIID, X, Y, II); 2340 Instruction *FNeg = UnaryOperator::CreateFNeg(NewCall); 2341 FNeg->copyIRFlags(II); 2342 return FNeg; 2343 } 2344 2345 // m(m(X, C2), C1) -> m(X, C) 2346 const APFloat *C1, *C2; 2347 if (auto *M = dyn_cast<IntrinsicInst>(Arg0)) { 2348 if (M->getIntrinsicID() == IID && match(Arg1, m_APFloat(C1)) && 2349 ((match(M->getArgOperand(0), m_Value(X)) && 2350 match(M->getArgOperand(1), m_APFloat(C2))) || 2351 (match(M->getArgOperand(1), m_Value(X)) && 2352 match(M->getArgOperand(0), m_APFloat(C2))))) { 2353 APFloat Res(0.0); 2354 switch (IID) { 2355 case Intrinsic::maxnum: 2356 Res = maxnum(*C1, *C2); 2357 break; 2358 case Intrinsic::minnum: 2359 Res = minnum(*C1, *C2); 2360 break; 2361 case Intrinsic::maximum: 2362 Res = maximum(*C1, *C2); 2363 break; 2364 case Intrinsic::minimum: 2365 Res = minimum(*C1, *C2); 2366 break; 2367 default: 2368 llvm_unreachable("unexpected intrinsic ID"); 2369 } 2370 Value *V = Builder.CreateBinaryIntrinsic( 2371 IID, X, ConstantFP::get(Arg0->getType(), Res), II); 2372 // TODO: Conservatively intersecting FMF. If Res == C2, the transform 2373 // was a simplification (so Arg0 and its original flags could 2374 // propagate?) 2375 if (auto *CI = dyn_cast<CallInst>(V)) 2376 CI->andIRFlags(M); 2377 return replaceInstUsesWith(*II, V); 2378 } 2379 } 2380 2381 // m((fpext X), (fpext Y)) -> fpext (m(X, Y)) 2382 if (match(Arg0, m_OneUse(m_FPExt(m_Value(X)))) && 2383 match(Arg1, m_OneUse(m_FPExt(m_Value(Y)))) && 2384 X->getType() == Y->getType()) { 2385 Value *NewCall = 2386 Builder.CreateBinaryIntrinsic(IID, X, Y, II, II->getName()); 2387 return new FPExtInst(NewCall, II->getType()); 2388 } 2389 2390 // max X, -X --> fabs X 2391 // min X, -X --> -(fabs X) 2392 // TODO: Remove one-use limitation? That is obviously better for max, 2393 // hence why we don't check for one-use for that. However, 2394 // it would be an extra instruction for min (fnabs), but 2395 // that is still likely better for analysis and codegen. 2396 auto IsMinMaxOrXNegX = [IID, &X](Value *Op0, Value *Op1) { 2397 if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_Specific(X))) 2398 return Op0->hasOneUse() || 2399 (IID != Intrinsic::minimum && IID != Intrinsic::minnum); 2400 return false; 2401 }; 2402 2403 if (IsMinMaxOrXNegX(Arg0, Arg1) || IsMinMaxOrXNegX(Arg1, Arg0)) { 2404 Value *R = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, II); 2405 if (IID == Intrinsic::minimum || IID == Intrinsic::minnum) 2406 R = Builder.CreateFNegFMF(R, II); 2407 return replaceInstUsesWith(*II, R); 2408 } 2409 2410 break; 2411 } 2412 case Intrinsic::matrix_multiply: { 2413 // Optimize negation in matrix multiplication. 2414 2415 // -A * -B -> A * B 2416 Value *A, *B; 2417 if (match(II->getArgOperand(0), m_FNeg(m_Value(A))) && 2418 match(II->getArgOperand(1), m_FNeg(m_Value(B)))) { 2419 replaceOperand(*II, 0, A); 2420 replaceOperand(*II, 1, B); 2421 return II; 2422 } 2423 2424 Value *Op0 = II->getOperand(0); 2425 Value *Op1 = II->getOperand(1); 2426 Value *OpNotNeg, *NegatedOp; 2427 unsigned NegatedOpArg, OtherOpArg; 2428 if (match(Op0, m_FNeg(m_Value(OpNotNeg)))) { 2429 NegatedOp = Op0; 2430 NegatedOpArg = 0; 2431 OtherOpArg = 1; 2432 } else if (match(Op1, m_FNeg(m_Value(OpNotNeg)))) { 2433 NegatedOp = Op1; 2434 NegatedOpArg = 1; 2435 OtherOpArg = 0; 2436 } else 2437 // Multiplication doesn't have a negated operand. 2438 break; 2439 2440 // Only optimize if the negated operand has only one use. 2441 if (!NegatedOp->hasOneUse()) 2442 break; 2443 2444 Value *OtherOp = II->getOperand(OtherOpArg); 2445 VectorType *RetTy = cast<VectorType>(II->getType()); 2446 VectorType *NegatedOpTy = cast<VectorType>(NegatedOp->getType()); 2447 VectorType *OtherOpTy = cast<VectorType>(OtherOp->getType()); 2448 ElementCount NegatedCount = NegatedOpTy->getElementCount(); 2449 ElementCount OtherCount = OtherOpTy->getElementCount(); 2450 ElementCount RetCount = RetTy->getElementCount(); 2451 // (-A) * B -> A * (-B), if it is cheaper to negate B and vice versa. 2452 if (ElementCount::isKnownGT(NegatedCount, OtherCount) && 2453 ElementCount::isKnownLT(OtherCount, RetCount)) { 2454 Value *InverseOtherOp = Builder.CreateFNeg(OtherOp); 2455 replaceOperand(*II, NegatedOpArg, OpNotNeg); 2456 replaceOperand(*II, OtherOpArg, InverseOtherOp); 2457 return II; 2458 } 2459 // (-A) * B -> -(A * B), if it is cheaper to negate the result 2460 if (ElementCount::isKnownGT(NegatedCount, RetCount)) { 2461 SmallVector<Value *, 5> NewArgs(II->args()); 2462 NewArgs[NegatedOpArg] = OpNotNeg; 2463 Instruction *NewMul = 2464 Builder.CreateIntrinsic(II->getType(), IID, NewArgs, II); 2465 return replaceInstUsesWith(*II, Builder.CreateFNegFMF(NewMul, II)); 2466 } 2467 break; 2468 } 2469 case Intrinsic::fmuladd: { 2470 // Try to simplify the underlying FMul. 2471 if (Value *V = simplifyFMulInst(II->getArgOperand(0), II->getArgOperand(1), 2472 II->getFastMathFlags(), 2473 SQ.getWithInstruction(II))) { 2474 auto *FAdd = BinaryOperator::CreateFAdd(V, II->getArgOperand(2)); 2475 FAdd->copyFastMathFlags(II); 2476 return FAdd; 2477 } 2478 2479 [[fallthrough]]; 2480 } 2481 case Intrinsic::fma: { 2482 // fma fneg(x), fneg(y), z -> fma x, y, z 2483 Value *Src0 = II->getArgOperand(0); 2484 Value *Src1 = II->getArgOperand(1); 2485 Value *X, *Y; 2486 if (match(Src0, m_FNeg(m_Value(X))) && match(Src1, m_FNeg(m_Value(Y)))) { 2487 replaceOperand(*II, 0, X); 2488 replaceOperand(*II, 1, Y); 2489 return II; 2490 } 2491 2492 // fma fabs(x), fabs(x), z -> fma x, x, z 2493 if (match(Src0, m_FAbs(m_Value(X))) && 2494 match(Src1, m_FAbs(m_Specific(X)))) { 2495 replaceOperand(*II, 0, X); 2496 replaceOperand(*II, 1, X); 2497 return II; 2498 } 2499 2500 // Try to simplify the underlying FMul. We can only apply simplifications 2501 // that do not require rounding. 2502 if (Value *V = simplifyFMAFMul(II->getArgOperand(0), II->getArgOperand(1), 2503 II->getFastMathFlags(), 2504 SQ.getWithInstruction(II))) { 2505 auto *FAdd = BinaryOperator::CreateFAdd(V, II->getArgOperand(2)); 2506 FAdd->copyFastMathFlags(II); 2507 return FAdd; 2508 } 2509 2510 // fma x, y, 0 -> fmul x, y 2511 // This is always valid for -0.0, but requires nsz for +0.0 as 2512 // -0.0 + 0.0 = 0.0, which would not be the same as the fmul on its own. 2513 if (match(II->getArgOperand(2), m_NegZeroFP()) || 2514 (match(II->getArgOperand(2), m_PosZeroFP()) && 2515 II->getFastMathFlags().noSignedZeros())) 2516 return BinaryOperator::CreateFMulFMF(Src0, Src1, II); 2517 2518 break; 2519 } 2520 case Intrinsic::copysign: { 2521 Value *Mag = II->getArgOperand(0), *Sign = II->getArgOperand(1); 2522 if (std::optional<bool> KnownSignBit = computeKnownFPSignBit( 2523 Sign, /*Depth=*/0, getSimplifyQuery().getWithInstruction(II))) { 2524 if (*KnownSignBit) { 2525 // If we know that the sign argument is negative, reduce to FNABS: 2526 // copysign Mag, -Sign --> fneg (fabs Mag) 2527 Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Mag, II); 2528 return replaceInstUsesWith(*II, Builder.CreateFNegFMF(Fabs, II)); 2529 } 2530 2531 // If we know that the sign argument is positive, reduce to FABS: 2532 // copysign Mag, +Sign --> fabs Mag 2533 Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Mag, II); 2534 return replaceInstUsesWith(*II, Fabs); 2535 } 2536 2537 // Propagate sign argument through nested calls: 2538 // copysign Mag, (copysign ?, X) --> copysign Mag, X 2539 Value *X; 2540 if (match(Sign, m_Intrinsic<Intrinsic::copysign>(m_Value(), m_Value(X)))) 2541 return replaceOperand(*II, 1, X); 2542 2543 // Clear sign-bit of constant magnitude: 2544 // copysign -MagC, X --> copysign MagC, X 2545 // TODO: Support constant folding for fabs 2546 const APFloat *MagC; 2547 if (match(Mag, m_APFloat(MagC)) && MagC->isNegative()) { 2548 APFloat PosMagC = *MagC; 2549 PosMagC.clearSign(); 2550 return replaceOperand(*II, 0, ConstantFP::get(Mag->getType(), PosMagC)); 2551 } 2552 2553 // Peek through changes of magnitude's sign-bit. This call rewrites those: 2554 // copysign (fabs X), Sign --> copysign X, Sign 2555 // copysign (fneg X), Sign --> copysign X, Sign 2556 if (match(Mag, m_FAbs(m_Value(X))) || match(Mag, m_FNeg(m_Value(X)))) 2557 return replaceOperand(*II, 0, X); 2558 2559 break; 2560 } 2561 case Intrinsic::fabs: { 2562 Value *Cond, *TVal, *FVal; 2563 Value *Arg = II->getArgOperand(0); 2564 Value *X; 2565 // fabs (-X) --> fabs (X) 2566 if (match(Arg, m_FNeg(m_Value(X)))) { 2567 CallInst *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, II); 2568 return replaceInstUsesWith(CI, Fabs); 2569 } 2570 2571 if (match(Arg, m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))) { 2572 // fabs (select Cond, TrueC, FalseC) --> select Cond, AbsT, AbsF 2573 if (isa<Constant>(TVal) || isa<Constant>(FVal)) { 2574 CallInst *AbsT = Builder.CreateCall(II->getCalledFunction(), {TVal}); 2575 CallInst *AbsF = Builder.CreateCall(II->getCalledFunction(), {FVal}); 2576 SelectInst *SI = SelectInst::Create(Cond, AbsT, AbsF); 2577 FastMathFlags FMF1 = II->getFastMathFlags(); 2578 FastMathFlags FMF2 = cast<SelectInst>(Arg)->getFastMathFlags(); 2579 FMF2.setNoSignedZeros(false); 2580 SI->setFastMathFlags(FMF1 | FMF2); 2581 return SI; 2582 } 2583 // fabs (select Cond, -FVal, FVal) --> fabs FVal 2584 if (match(TVal, m_FNeg(m_Specific(FVal)))) 2585 return replaceOperand(*II, 0, FVal); 2586 // fabs (select Cond, TVal, -TVal) --> fabs TVal 2587 if (match(FVal, m_FNeg(m_Specific(TVal)))) 2588 return replaceOperand(*II, 0, TVal); 2589 } 2590 2591 Value *Magnitude, *Sign; 2592 if (match(II->getArgOperand(0), 2593 m_CopySign(m_Value(Magnitude), m_Value(Sign)))) { 2594 // fabs (copysign x, y) -> (fabs x) 2595 CallInst *AbsSign = 2596 Builder.CreateCall(II->getCalledFunction(), {Magnitude}); 2597 AbsSign->copyFastMathFlags(II); 2598 return replaceInstUsesWith(*II, AbsSign); 2599 } 2600 2601 [[fallthrough]]; 2602 } 2603 case Intrinsic::ceil: 2604 case Intrinsic::floor: 2605 case Intrinsic::round: 2606 case Intrinsic::roundeven: 2607 case Intrinsic::nearbyint: 2608 case Intrinsic::rint: 2609 case Intrinsic::trunc: { 2610 Value *ExtSrc; 2611 if (match(II->getArgOperand(0), m_OneUse(m_FPExt(m_Value(ExtSrc))))) { 2612 // Narrow the call: intrinsic (fpext x) -> fpext (intrinsic x) 2613 Value *NarrowII = Builder.CreateUnaryIntrinsic(IID, ExtSrc, II); 2614 return new FPExtInst(NarrowII, II->getType()); 2615 } 2616 break; 2617 } 2618 case Intrinsic::cos: 2619 case Intrinsic::amdgcn_cos: { 2620 Value *X, *Sign; 2621 Value *Src = II->getArgOperand(0); 2622 if (match(Src, m_FNeg(m_Value(X))) || match(Src, m_FAbs(m_Value(X))) || 2623 match(Src, m_CopySign(m_Value(X), m_Value(Sign)))) { 2624 // cos(-x) --> cos(x) 2625 // cos(fabs(x)) --> cos(x) 2626 // cos(copysign(x, y)) --> cos(x) 2627 return replaceOperand(*II, 0, X); 2628 } 2629 break; 2630 } 2631 case Intrinsic::sin: 2632 case Intrinsic::amdgcn_sin: { 2633 Value *X; 2634 if (match(II->getArgOperand(0), m_OneUse(m_FNeg(m_Value(X))))) { 2635 // sin(-x) --> -sin(x) 2636 Value *NewSin = Builder.CreateUnaryIntrinsic(IID, X, II); 2637 return UnaryOperator::CreateFNegFMF(NewSin, II); 2638 } 2639 break; 2640 } 2641 case Intrinsic::ldexp: { 2642 // ldexp(ldexp(x, a), b) -> ldexp(x, a + b) 2643 // 2644 // The danger is if the first ldexp would overflow to infinity or underflow 2645 // to zero, but the combined exponent avoids it. We ignore this with 2646 // reassoc. 2647 // 2648 // It's also safe to fold if we know both exponents are >= 0 or <= 0 since 2649 // it would just double down on the overflow/underflow which would occur 2650 // anyway. 2651 // 2652 // TODO: Could do better if we had range tracking for the input value 2653 // exponent. Also could broaden sign check to cover == 0 case. 2654 Value *Src = II->getArgOperand(0); 2655 Value *Exp = II->getArgOperand(1); 2656 Value *InnerSrc; 2657 Value *InnerExp; 2658 if (match(Src, m_OneUse(m_Intrinsic<Intrinsic::ldexp>( 2659 m_Value(InnerSrc), m_Value(InnerExp)))) && 2660 Exp->getType() == InnerExp->getType()) { 2661 FastMathFlags FMF = II->getFastMathFlags(); 2662 FastMathFlags InnerFlags = cast<FPMathOperator>(Src)->getFastMathFlags(); 2663 2664 if ((FMF.allowReassoc() && InnerFlags.allowReassoc()) || 2665 signBitMustBeTheSame(Exp, InnerExp, SQ.getWithInstruction(II))) { 2666 // TODO: Add nsw/nuw probably safe if integer type exceeds exponent 2667 // width. 2668 Value *NewExp = Builder.CreateAdd(InnerExp, Exp); 2669 II->setArgOperand(1, NewExp); 2670 II->setFastMathFlags(InnerFlags); // Or the inner flags. 2671 return replaceOperand(*II, 0, InnerSrc); 2672 } 2673 } 2674 2675 // ldexp(x, zext(i1 y)) -> fmul x, (select y, 2.0, 1.0) 2676 // ldexp(x, sext(i1 y)) -> fmul x, (select y, 0.5, 1.0) 2677 Value *ExtSrc; 2678 if (match(Exp, m_ZExt(m_Value(ExtSrc))) && 2679 ExtSrc->getType()->getScalarSizeInBits() == 1) { 2680 Value *Select = 2681 Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 2.0), 2682 ConstantFP::get(II->getType(), 1.0)); 2683 return BinaryOperator::CreateFMulFMF(Src, Select, II); 2684 } 2685 if (match(Exp, m_SExt(m_Value(ExtSrc))) && 2686 ExtSrc->getType()->getScalarSizeInBits() == 1) { 2687 Value *Select = 2688 Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 0.5), 2689 ConstantFP::get(II->getType(), 1.0)); 2690 return BinaryOperator::CreateFMulFMF(Src, Select, II); 2691 } 2692 2693 // ldexp(x, c ? exp : 0) -> c ? ldexp(x, exp) : x 2694 // ldexp(x, c ? 0 : exp) -> c ? x : ldexp(x, exp) 2695 /// 2696 // TODO: If we cared, should insert a canonicalize for x 2697 Value *SelectCond, *SelectLHS, *SelectRHS; 2698 if (match(II->getArgOperand(1), 2699 m_OneUse(m_Select(m_Value(SelectCond), m_Value(SelectLHS), 2700 m_Value(SelectRHS))))) { 2701 Value *NewLdexp = nullptr; 2702 Value *Select = nullptr; 2703 if (match(SelectRHS, m_ZeroInt())) { 2704 NewLdexp = Builder.CreateLdexp(Src, SelectLHS); 2705 Select = Builder.CreateSelect(SelectCond, NewLdexp, Src); 2706 } else if (match(SelectLHS, m_ZeroInt())) { 2707 NewLdexp = Builder.CreateLdexp(Src, SelectRHS); 2708 Select = Builder.CreateSelect(SelectCond, Src, NewLdexp); 2709 } 2710 2711 if (NewLdexp) { 2712 Select->takeName(II); 2713 cast<Instruction>(NewLdexp)->copyFastMathFlags(II); 2714 return replaceInstUsesWith(*II, Select); 2715 } 2716 } 2717 2718 break; 2719 } 2720 case Intrinsic::ptrauth_auth: 2721 case Intrinsic::ptrauth_resign: { 2722 // (sign|resign) + (auth|resign) can be folded by omitting the middle 2723 // sign+auth component if the key and discriminator match. 2724 bool NeedSign = II->getIntrinsicID() == Intrinsic::ptrauth_resign; 2725 Value *Ptr = II->getArgOperand(0); 2726 Value *Key = II->getArgOperand(1); 2727 Value *Disc = II->getArgOperand(2); 2728 2729 // AuthKey will be the key we need to end up authenticating against in 2730 // whatever we replace this sequence with. 2731 Value *AuthKey = nullptr, *AuthDisc = nullptr, *BasePtr; 2732 if (const auto *CI = dyn_cast<CallBase>(Ptr)) { 2733 BasePtr = CI->getArgOperand(0); 2734 if (CI->getIntrinsicID() == Intrinsic::ptrauth_sign) { 2735 if (CI->getArgOperand(1) != Key || CI->getArgOperand(2) != Disc) 2736 break; 2737 } else if (CI->getIntrinsicID() == Intrinsic::ptrauth_resign) { 2738 if (CI->getArgOperand(3) != Key || CI->getArgOperand(4) != Disc) 2739 break; 2740 AuthKey = CI->getArgOperand(1); 2741 AuthDisc = CI->getArgOperand(2); 2742 } else 2743 break; 2744 } else if (const auto *PtrToInt = dyn_cast<PtrToIntOperator>(Ptr)) { 2745 // ptrauth constants are equivalent to a call to @llvm.ptrauth.sign for 2746 // our purposes, so check for that too. 2747 const auto *CPA = dyn_cast<ConstantPtrAuth>(PtrToInt->getOperand(0)); 2748 if (!CPA || !CPA->isKnownCompatibleWith(Key, Disc, DL)) 2749 break; 2750 2751 // resign(ptrauth(p,ks,ds),ks,ds,kr,dr) -> ptrauth(p,kr,dr) 2752 if (NeedSign && isa<ConstantInt>(II->getArgOperand(4))) { 2753 auto *SignKey = cast<ConstantInt>(II->getArgOperand(3)); 2754 auto *SignDisc = cast<ConstantInt>(II->getArgOperand(4)); 2755 auto *SignAddrDisc = ConstantPointerNull::get(Builder.getPtrTy()); 2756 auto *NewCPA = ConstantPtrAuth::get(CPA->getPointer(), SignKey, 2757 SignDisc, SignAddrDisc); 2758 replaceInstUsesWith( 2759 *II, ConstantExpr::getPointerCast(NewCPA, II->getType())); 2760 return eraseInstFromFunction(*II); 2761 } 2762 2763 // auth(ptrauth(p,k,d),k,d) -> p 2764 BasePtr = Builder.CreatePtrToInt(CPA->getPointer(), II->getType()); 2765 } else 2766 break; 2767 2768 unsigned NewIntrin; 2769 if (AuthKey && NeedSign) { 2770 // resign(0,1) + resign(1,2) = resign(0, 2) 2771 NewIntrin = Intrinsic::ptrauth_resign; 2772 } else if (AuthKey) { 2773 // resign(0,1) + auth(1) = auth(0) 2774 NewIntrin = Intrinsic::ptrauth_auth; 2775 } else if (NeedSign) { 2776 // sign(0) + resign(0, 1) = sign(1) 2777 NewIntrin = Intrinsic::ptrauth_sign; 2778 } else { 2779 // sign(0) + auth(0) = nop 2780 replaceInstUsesWith(*II, BasePtr); 2781 return eraseInstFromFunction(*II); 2782 } 2783 2784 SmallVector<Value *, 4> CallArgs; 2785 CallArgs.push_back(BasePtr); 2786 if (AuthKey) { 2787 CallArgs.push_back(AuthKey); 2788 CallArgs.push_back(AuthDisc); 2789 } 2790 2791 if (NeedSign) { 2792 CallArgs.push_back(II->getArgOperand(3)); 2793 CallArgs.push_back(II->getArgOperand(4)); 2794 } 2795 2796 Function *NewFn = Intrinsic::getDeclaration(II->getModule(), NewIntrin); 2797 return CallInst::Create(NewFn, CallArgs); 2798 } 2799 case Intrinsic::arm_neon_vtbl1: 2800 case Intrinsic::aarch64_neon_tbl1: 2801 if (Value *V = simplifyNeonTbl1(*II, Builder)) 2802 return replaceInstUsesWith(*II, V); 2803 break; 2804 2805 case Intrinsic::arm_neon_vmulls: 2806 case Intrinsic::arm_neon_vmullu: 2807 case Intrinsic::aarch64_neon_smull: 2808 case Intrinsic::aarch64_neon_umull: { 2809 Value *Arg0 = II->getArgOperand(0); 2810 Value *Arg1 = II->getArgOperand(1); 2811 2812 // Handle mul by zero first: 2813 if (isa<ConstantAggregateZero>(Arg0) || isa<ConstantAggregateZero>(Arg1)) { 2814 return replaceInstUsesWith(CI, ConstantAggregateZero::get(II->getType())); 2815 } 2816 2817 // Check for constant LHS & RHS - in this case we just simplify. 2818 bool Zext = (IID == Intrinsic::arm_neon_vmullu || 2819 IID == Intrinsic::aarch64_neon_umull); 2820 VectorType *NewVT = cast<VectorType>(II->getType()); 2821 if (Constant *CV0 = dyn_cast<Constant>(Arg0)) { 2822 if (Constant *CV1 = dyn_cast<Constant>(Arg1)) { 2823 Value *V0 = Builder.CreateIntCast(CV0, NewVT, /*isSigned=*/!Zext); 2824 Value *V1 = Builder.CreateIntCast(CV1, NewVT, /*isSigned=*/!Zext); 2825 return replaceInstUsesWith(CI, Builder.CreateMul(V0, V1)); 2826 } 2827 2828 // Couldn't simplify - canonicalize constant to the RHS. 2829 std::swap(Arg0, Arg1); 2830 } 2831 2832 // Handle mul by one: 2833 if (Constant *CV1 = dyn_cast<Constant>(Arg1)) 2834 if (ConstantInt *Splat = 2835 dyn_cast_or_null<ConstantInt>(CV1->getSplatValue())) 2836 if (Splat->isOne()) 2837 return CastInst::CreateIntegerCast(Arg0, II->getType(), 2838 /*isSigned=*/!Zext); 2839 2840 break; 2841 } 2842 case Intrinsic::arm_neon_aesd: 2843 case Intrinsic::arm_neon_aese: 2844 case Intrinsic::aarch64_crypto_aesd: 2845 case Intrinsic::aarch64_crypto_aese: { 2846 Value *DataArg = II->getArgOperand(0); 2847 Value *KeyArg = II->getArgOperand(1); 2848 2849 // Try to use the builtin XOR in AESE and AESD to eliminate a prior XOR 2850 Value *Data, *Key; 2851 if (match(KeyArg, m_ZeroInt()) && 2852 match(DataArg, m_Xor(m_Value(Data), m_Value(Key)))) { 2853 replaceOperand(*II, 0, Data); 2854 replaceOperand(*II, 1, Key); 2855 return II; 2856 } 2857 break; 2858 } 2859 case Intrinsic::hexagon_V6_vandvrt: 2860 case Intrinsic::hexagon_V6_vandvrt_128B: { 2861 // Simplify Q -> V -> Q conversion. 2862 if (auto Op0 = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 2863 Intrinsic::ID ID0 = Op0->getIntrinsicID(); 2864 if (ID0 != Intrinsic::hexagon_V6_vandqrt && 2865 ID0 != Intrinsic::hexagon_V6_vandqrt_128B) 2866 break; 2867 Value *Bytes = Op0->getArgOperand(1), *Mask = II->getArgOperand(1); 2868 uint64_t Bytes1 = computeKnownBits(Bytes, 0, Op0).One.getZExtValue(); 2869 uint64_t Mask1 = computeKnownBits(Mask, 0, II).One.getZExtValue(); 2870 // Check if every byte has common bits in Bytes and Mask. 2871 uint64_t C = Bytes1 & Mask1; 2872 if ((C & 0xFF) && (C & 0xFF00) && (C & 0xFF0000) && (C & 0xFF000000)) 2873 return replaceInstUsesWith(*II, Op0->getArgOperand(0)); 2874 } 2875 break; 2876 } 2877 case Intrinsic::stackrestore: { 2878 enum class ClassifyResult { 2879 None, 2880 Alloca, 2881 StackRestore, 2882 CallWithSideEffects, 2883 }; 2884 auto Classify = [](const Instruction *I) { 2885 if (isa<AllocaInst>(I)) 2886 return ClassifyResult::Alloca; 2887 2888 if (auto *CI = dyn_cast<CallInst>(I)) { 2889 if (auto *II = dyn_cast<IntrinsicInst>(CI)) { 2890 if (II->getIntrinsicID() == Intrinsic::stackrestore) 2891 return ClassifyResult::StackRestore; 2892 2893 if (II->mayHaveSideEffects()) 2894 return ClassifyResult::CallWithSideEffects; 2895 } else { 2896 // Consider all non-intrinsic calls to be side effects 2897 return ClassifyResult::CallWithSideEffects; 2898 } 2899 } 2900 2901 return ClassifyResult::None; 2902 }; 2903 2904 // If the stacksave and the stackrestore are in the same BB, and there is 2905 // no intervening call, alloca, or stackrestore of a different stacksave, 2906 // remove the restore. This can happen when variable allocas are DCE'd. 2907 if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 2908 if (SS->getIntrinsicID() == Intrinsic::stacksave && 2909 SS->getParent() == II->getParent()) { 2910 BasicBlock::iterator BI(SS); 2911 bool CannotRemove = false; 2912 for (++BI; &*BI != II; ++BI) { 2913 switch (Classify(&*BI)) { 2914 case ClassifyResult::None: 2915 // So far so good, look at next instructions. 2916 break; 2917 2918 case ClassifyResult::StackRestore: 2919 // If we found an intervening stackrestore for a different 2920 // stacksave, we can't remove the stackrestore. Otherwise, continue. 2921 if (cast<IntrinsicInst>(*BI).getArgOperand(0) != SS) 2922 CannotRemove = true; 2923 break; 2924 2925 case ClassifyResult::Alloca: 2926 case ClassifyResult::CallWithSideEffects: 2927 // If we found an alloca, a non-intrinsic call, or an intrinsic 2928 // call with side effects, we can't remove the stackrestore. 2929 CannotRemove = true; 2930 break; 2931 } 2932 if (CannotRemove) 2933 break; 2934 } 2935 2936 if (!CannotRemove) 2937 return eraseInstFromFunction(CI); 2938 } 2939 } 2940 2941 // Scan down this block to see if there is another stack restore in the 2942 // same block without an intervening call/alloca. 2943 BasicBlock::iterator BI(II); 2944 Instruction *TI = II->getParent()->getTerminator(); 2945 bool CannotRemove = false; 2946 for (++BI; &*BI != TI; ++BI) { 2947 switch (Classify(&*BI)) { 2948 case ClassifyResult::None: 2949 // So far so good, look at next instructions. 2950 break; 2951 2952 case ClassifyResult::StackRestore: 2953 // If there is a stackrestore below this one, remove this one. 2954 return eraseInstFromFunction(CI); 2955 2956 case ClassifyResult::Alloca: 2957 case ClassifyResult::CallWithSideEffects: 2958 // If we found an alloca, a non-intrinsic call, or an intrinsic call 2959 // with side effects (such as llvm.stacksave and llvm.read_register), 2960 // we can't remove the stack restore. 2961 CannotRemove = true; 2962 break; 2963 } 2964 if (CannotRemove) 2965 break; 2966 } 2967 2968 // If the stack restore is in a return, resume, or unwind block and if there 2969 // are no allocas or calls between the restore and the return, nuke the 2970 // restore. 2971 if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI))) 2972 return eraseInstFromFunction(CI); 2973 break; 2974 } 2975 case Intrinsic::lifetime_end: 2976 // Asan needs to poison memory to detect invalid access which is possible 2977 // even for empty lifetime range. 2978 if (II->getFunction()->hasFnAttribute(Attribute::SanitizeAddress) || 2979 II->getFunction()->hasFnAttribute(Attribute::SanitizeMemory) || 2980 II->getFunction()->hasFnAttribute(Attribute::SanitizeHWAddress)) 2981 break; 2982 2983 if (removeTriviallyEmptyRange(*II, *this, [](const IntrinsicInst &I) { 2984 return I.getIntrinsicID() == Intrinsic::lifetime_start; 2985 })) 2986 return nullptr; 2987 break; 2988 case Intrinsic::assume: { 2989 Value *IIOperand = II->getArgOperand(0); 2990 SmallVector<OperandBundleDef, 4> OpBundles; 2991 II->getOperandBundlesAsDefs(OpBundles); 2992 2993 /// This will remove the boolean Condition from the assume given as 2994 /// argument and remove the assume if it becomes useless. 2995 /// always returns nullptr for use as a return values. 2996 auto RemoveConditionFromAssume = [&](Instruction *Assume) -> Instruction * { 2997 assert(isa<AssumeInst>(Assume)); 2998 if (isAssumeWithEmptyBundle(*cast<AssumeInst>(II))) 2999 return eraseInstFromFunction(CI); 3000 replaceUse(II->getOperandUse(0), ConstantInt::getTrue(II->getContext())); 3001 return nullptr; 3002 }; 3003 // Remove an assume if it is followed by an identical assume. 3004 // TODO: Do we need this? Unless there are conflicting assumptions, the 3005 // computeKnownBits(IIOperand) below here eliminates redundant assumes. 3006 Instruction *Next = II->getNextNonDebugInstruction(); 3007 if (match(Next, m_Intrinsic<Intrinsic::assume>(m_Specific(IIOperand)))) 3008 return RemoveConditionFromAssume(Next); 3009 3010 // Canonicalize assume(a && b) -> assume(a); assume(b); 3011 // Note: New assumption intrinsics created here are registered by 3012 // the InstCombineIRInserter object. 3013 FunctionType *AssumeIntrinsicTy = II->getFunctionType(); 3014 Value *AssumeIntrinsic = II->getCalledOperand(); 3015 Value *A, *B; 3016 if (match(IIOperand, m_LogicalAnd(m_Value(A), m_Value(B)))) { 3017 Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, A, OpBundles, 3018 II->getName()); 3019 Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, B, II->getName()); 3020 return eraseInstFromFunction(*II); 3021 } 3022 // assume(!(a || b)) -> assume(!a); assume(!b); 3023 if (match(IIOperand, m_Not(m_LogicalOr(m_Value(A), m_Value(B))))) { 3024 Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, 3025 Builder.CreateNot(A), OpBundles, II->getName()); 3026 Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, 3027 Builder.CreateNot(B), II->getName()); 3028 return eraseInstFromFunction(*II); 3029 } 3030 3031 // assume( (load addr) != null ) -> add 'nonnull' metadata to load 3032 // (if assume is valid at the load) 3033 CmpInst::Predicate Pred; 3034 Instruction *LHS; 3035 if (match(IIOperand, m_ICmp(Pred, m_Instruction(LHS), m_Zero())) && 3036 Pred == ICmpInst::ICMP_NE && LHS->getOpcode() == Instruction::Load && 3037 LHS->getType()->isPointerTy() && 3038 isValidAssumeForContext(II, LHS, &DT)) { 3039 MDNode *MD = MDNode::get(II->getContext(), std::nullopt); 3040 LHS->setMetadata(LLVMContext::MD_nonnull, MD); 3041 LHS->setMetadata(LLVMContext::MD_noundef, MD); 3042 return RemoveConditionFromAssume(II); 3043 3044 // TODO: apply nonnull return attributes to calls and invokes 3045 // TODO: apply range metadata for range check patterns? 3046 } 3047 3048 // Separate storage assumptions apply to the underlying allocations, not any 3049 // particular pointer within them. When evaluating the hints for AA purposes 3050 // we getUnderlyingObject them; by precomputing the answers here we can 3051 // avoid having to do so repeatedly there. 3052 for (unsigned Idx = 0; Idx < II->getNumOperandBundles(); Idx++) { 3053 OperandBundleUse OBU = II->getOperandBundleAt(Idx); 3054 if (OBU.getTagName() == "separate_storage") { 3055 assert(OBU.Inputs.size() == 2); 3056 auto MaybeSimplifyHint = [&](const Use &U) { 3057 Value *Hint = U.get(); 3058 // Not having a limit is safe because InstCombine removes unreachable 3059 // code. 3060 Value *UnderlyingObject = getUnderlyingObject(Hint, /*MaxLookup*/ 0); 3061 if (Hint != UnderlyingObject) 3062 replaceUse(const_cast<Use &>(U), UnderlyingObject); 3063 }; 3064 MaybeSimplifyHint(OBU.Inputs[0]); 3065 MaybeSimplifyHint(OBU.Inputs[1]); 3066 } 3067 } 3068 3069 // Convert nonnull assume like: 3070 // %A = icmp ne i32* %PTR, null 3071 // call void @llvm.assume(i1 %A) 3072 // into 3073 // call void @llvm.assume(i1 true) [ "nonnull"(i32* %PTR) ] 3074 if (EnableKnowledgeRetention && 3075 match(IIOperand, m_Cmp(Pred, m_Value(A), m_Zero())) && 3076 Pred == CmpInst::ICMP_NE && A->getType()->isPointerTy()) { 3077 if (auto *Replacement = buildAssumeFromKnowledge( 3078 {RetainedKnowledge{Attribute::NonNull, 0, A}}, Next, &AC, &DT)) { 3079 3080 Replacement->insertBefore(Next); 3081 AC.registerAssumption(Replacement); 3082 return RemoveConditionFromAssume(II); 3083 } 3084 } 3085 3086 // Convert alignment assume like: 3087 // %B = ptrtoint i32* %A to i64 3088 // %C = and i64 %B, Constant 3089 // %D = icmp eq i64 %C, 0 3090 // call void @llvm.assume(i1 %D) 3091 // into 3092 // call void @llvm.assume(i1 true) [ "align"(i32* [[A]], i64 Constant + 1)] 3093 uint64_t AlignMask; 3094 if (EnableKnowledgeRetention && 3095 match(IIOperand, 3096 m_Cmp(Pred, m_And(m_Value(A), m_ConstantInt(AlignMask)), 3097 m_Zero())) && 3098 Pred == CmpInst::ICMP_EQ) { 3099 if (isPowerOf2_64(AlignMask + 1)) { 3100 uint64_t Offset = 0; 3101 match(A, m_Add(m_Value(A), m_ConstantInt(Offset))); 3102 if (match(A, m_PtrToInt(m_Value(A)))) { 3103 /// Note: this doesn't preserve the offset information but merges 3104 /// offset and alignment. 3105 /// TODO: we can generate a GEP instead of merging the alignment with 3106 /// the offset. 3107 RetainedKnowledge RK{Attribute::Alignment, 3108 (unsigned)MinAlign(Offset, AlignMask + 1), A}; 3109 if (auto *Replacement = 3110 buildAssumeFromKnowledge(RK, Next, &AC, &DT)) { 3111 3112 Replacement->insertAfter(II); 3113 AC.registerAssumption(Replacement); 3114 } 3115 return RemoveConditionFromAssume(II); 3116 } 3117 } 3118 } 3119 3120 /// Canonicalize Knowledge in operand bundles. 3121 if (EnableKnowledgeRetention && II->hasOperandBundles()) { 3122 for (unsigned Idx = 0; Idx < II->getNumOperandBundles(); Idx++) { 3123 auto &BOI = II->bundle_op_info_begin()[Idx]; 3124 RetainedKnowledge RK = 3125 llvm::getKnowledgeFromBundle(cast<AssumeInst>(*II), BOI); 3126 if (BOI.End - BOI.Begin > 2) 3127 continue; // Prevent reducing knowledge in an align with offset since 3128 // extracting a RetainedKnowledge from them looses offset 3129 // information 3130 RetainedKnowledge CanonRK = 3131 llvm::simplifyRetainedKnowledge(cast<AssumeInst>(II), RK, 3132 &getAssumptionCache(), 3133 &getDominatorTree()); 3134 if (CanonRK == RK) 3135 continue; 3136 if (!CanonRK) { 3137 if (BOI.End - BOI.Begin > 0) { 3138 Worklist.pushValue(II->op_begin()[BOI.Begin]); 3139 Value::dropDroppableUse(II->op_begin()[BOI.Begin]); 3140 } 3141 continue; 3142 } 3143 assert(RK.AttrKind == CanonRK.AttrKind); 3144 if (BOI.End - BOI.Begin > 0) 3145 II->op_begin()[BOI.Begin].set(CanonRK.WasOn); 3146 if (BOI.End - BOI.Begin > 1) 3147 II->op_begin()[BOI.Begin + 1].set(ConstantInt::get( 3148 Type::getInt64Ty(II->getContext()), CanonRK.ArgValue)); 3149 if (RK.WasOn) 3150 Worklist.pushValue(RK.WasOn); 3151 return II; 3152 } 3153 } 3154 3155 // If there is a dominating assume with the same condition as this one, 3156 // then this one is redundant, and should be removed. 3157 KnownBits Known(1); 3158 computeKnownBits(IIOperand, Known, 0, II); 3159 if (Known.isAllOnes() && isAssumeWithEmptyBundle(cast<AssumeInst>(*II))) 3160 return eraseInstFromFunction(*II); 3161 3162 // assume(false) is unreachable. 3163 if (match(IIOperand, m_CombineOr(m_Zero(), m_Undef()))) { 3164 CreateNonTerminatorUnreachable(II); 3165 return eraseInstFromFunction(*II); 3166 } 3167 3168 // Update the cache of affected values for this assumption (we might be 3169 // here because we just simplified the condition). 3170 AC.updateAffectedValues(cast<AssumeInst>(II)); 3171 break; 3172 } 3173 case Intrinsic::experimental_guard: { 3174 // Is this guard followed by another guard? We scan forward over a small 3175 // fixed window of instructions to handle common cases with conditions 3176 // computed between guards. 3177 Instruction *NextInst = II->getNextNonDebugInstruction(); 3178 for (unsigned i = 0; i < GuardWideningWindow; i++) { 3179 // Note: Using context-free form to avoid compile time blow up 3180 if (!isSafeToSpeculativelyExecute(NextInst)) 3181 break; 3182 NextInst = NextInst->getNextNonDebugInstruction(); 3183 } 3184 Value *NextCond = nullptr; 3185 if (match(NextInst, 3186 m_Intrinsic<Intrinsic::experimental_guard>(m_Value(NextCond)))) { 3187 Value *CurrCond = II->getArgOperand(0); 3188 3189 // Remove a guard that it is immediately preceded by an identical guard. 3190 // Otherwise canonicalize guard(a); guard(b) -> guard(a & b). 3191 if (CurrCond != NextCond) { 3192 Instruction *MoveI = II->getNextNonDebugInstruction(); 3193 while (MoveI != NextInst) { 3194 auto *Temp = MoveI; 3195 MoveI = MoveI->getNextNonDebugInstruction(); 3196 Temp->moveBefore(II); 3197 } 3198 replaceOperand(*II, 0, Builder.CreateAnd(CurrCond, NextCond)); 3199 } 3200 eraseInstFromFunction(*NextInst); 3201 return II; 3202 } 3203 break; 3204 } 3205 case Intrinsic::vector_insert: { 3206 Value *Vec = II->getArgOperand(0); 3207 Value *SubVec = II->getArgOperand(1); 3208 Value *Idx = II->getArgOperand(2); 3209 auto *DstTy = dyn_cast<FixedVectorType>(II->getType()); 3210 auto *VecTy = dyn_cast<FixedVectorType>(Vec->getType()); 3211 auto *SubVecTy = dyn_cast<FixedVectorType>(SubVec->getType()); 3212 3213 // Only canonicalize if the destination vector, Vec, and SubVec are all 3214 // fixed vectors. 3215 if (DstTy && VecTy && SubVecTy) { 3216 unsigned DstNumElts = DstTy->getNumElements(); 3217 unsigned VecNumElts = VecTy->getNumElements(); 3218 unsigned SubVecNumElts = SubVecTy->getNumElements(); 3219 unsigned IdxN = cast<ConstantInt>(Idx)->getZExtValue(); 3220 3221 // An insert that entirely overwrites Vec with SubVec is a nop. 3222 if (VecNumElts == SubVecNumElts) 3223 return replaceInstUsesWith(CI, SubVec); 3224 3225 // Widen SubVec into a vector of the same width as Vec, since 3226 // shufflevector requires the two input vectors to be the same width. 3227 // Elements beyond the bounds of SubVec within the widened vector are 3228 // undefined. 3229 SmallVector<int, 8> WidenMask; 3230 unsigned i; 3231 for (i = 0; i != SubVecNumElts; ++i) 3232 WidenMask.push_back(i); 3233 for (; i != VecNumElts; ++i) 3234 WidenMask.push_back(PoisonMaskElem); 3235 3236 Value *WidenShuffle = Builder.CreateShuffleVector(SubVec, WidenMask); 3237 3238 SmallVector<int, 8> Mask; 3239 for (unsigned i = 0; i != IdxN; ++i) 3240 Mask.push_back(i); 3241 for (unsigned i = DstNumElts; i != DstNumElts + SubVecNumElts; ++i) 3242 Mask.push_back(i); 3243 for (unsigned i = IdxN + SubVecNumElts; i != DstNumElts; ++i) 3244 Mask.push_back(i); 3245 3246 Value *Shuffle = Builder.CreateShuffleVector(Vec, WidenShuffle, Mask); 3247 return replaceInstUsesWith(CI, Shuffle); 3248 } 3249 break; 3250 } 3251 case Intrinsic::vector_extract: { 3252 Value *Vec = II->getArgOperand(0); 3253 Value *Idx = II->getArgOperand(1); 3254 3255 Type *ReturnType = II->getType(); 3256 // (extract_vector (insert_vector InsertTuple, InsertValue, InsertIdx), 3257 // ExtractIdx) 3258 unsigned ExtractIdx = cast<ConstantInt>(Idx)->getZExtValue(); 3259 Value *InsertTuple, *InsertIdx, *InsertValue; 3260 if (match(Vec, m_Intrinsic<Intrinsic::vector_insert>(m_Value(InsertTuple), 3261 m_Value(InsertValue), 3262 m_Value(InsertIdx))) && 3263 InsertValue->getType() == ReturnType) { 3264 unsigned Index = cast<ConstantInt>(InsertIdx)->getZExtValue(); 3265 // Case where we get the same index right after setting it. 3266 // extract.vector(insert.vector(InsertTuple, InsertValue, Idx), Idx) --> 3267 // InsertValue 3268 if (ExtractIdx == Index) 3269 return replaceInstUsesWith(CI, InsertValue); 3270 // If we are getting a different index than what was set in the 3271 // insert.vector intrinsic. We can just set the input tuple to the one up 3272 // in the chain. extract.vector(insert.vector(InsertTuple, InsertValue, 3273 // InsertIndex), ExtractIndex) 3274 // --> extract.vector(InsertTuple, ExtractIndex) 3275 else 3276 return replaceOperand(CI, 0, InsertTuple); 3277 } 3278 3279 auto *DstTy = dyn_cast<VectorType>(ReturnType); 3280 auto *VecTy = dyn_cast<VectorType>(Vec->getType()); 3281 3282 if (DstTy && VecTy) { 3283 auto DstEltCnt = DstTy->getElementCount(); 3284 auto VecEltCnt = VecTy->getElementCount(); 3285 unsigned IdxN = cast<ConstantInt>(Idx)->getZExtValue(); 3286 3287 // Extracting the entirety of Vec is a nop. 3288 if (DstEltCnt == VecTy->getElementCount()) { 3289 replaceInstUsesWith(CI, Vec); 3290 return eraseInstFromFunction(CI); 3291 } 3292 3293 // Only canonicalize to shufflevector if the destination vector and 3294 // Vec are fixed vectors. 3295 if (VecEltCnt.isScalable() || DstEltCnt.isScalable()) 3296 break; 3297 3298 SmallVector<int, 8> Mask; 3299 for (unsigned i = 0; i != DstEltCnt.getKnownMinValue(); ++i) 3300 Mask.push_back(IdxN + i); 3301 3302 Value *Shuffle = Builder.CreateShuffleVector(Vec, Mask); 3303 return replaceInstUsesWith(CI, Shuffle); 3304 } 3305 break; 3306 } 3307 case Intrinsic::vector_reverse: { 3308 Value *BO0, *BO1, *X, *Y; 3309 Value *Vec = II->getArgOperand(0); 3310 if (match(Vec, m_OneUse(m_BinOp(m_Value(BO0), m_Value(BO1))))) { 3311 auto *OldBinOp = cast<BinaryOperator>(Vec); 3312 if (match(BO0, m_VecReverse(m_Value(X)))) { 3313 // rev(binop rev(X), rev(Y)) --> binop X, Y 3314 if (match(BO1, m_VecReverse(m_Value(Y)))) 3315 return replaceInstUsesWith(CI, BinaryOperator::CreateWithCopiedFlags( 3316 OldBinOp->getOpcode(), X, Y, 3317 OldBinOp, OldBinOp->getName(), 3318 II->getIterator())); 3319 // rev(binop rev(X), BO1Splat) --> binop X, BO1Splat 3320 if (isSplatValue(BO1)) 3321 return replaceInstUsesWith(CI, BinaryOperator::CreateWithCopiedFlags( 3322 OldBinOp->getOpcode(), X, BO1, 3323 OldBinOp, OldBinOp->getName(), 3324 II->getIterator())); 3325 } 3326 // rev(binop BO0Splat, rev(Y)) --> binop BO0Splat, Y 3327 if (match(BO1, m_VecReverse(m_Value(Y))) && isSplatValue(BO0)) 3328 return replaceInstUsesWith(CI, 3329 BinaryOperator::CreateWithCopiedFlags( 3330 OldBinOp->getOpcode(), BO0, Y, OldBinOp, 3331 OldBinOp->getName(), II->getIterator())); 3332 } 3333 // rev(unop rev(X)) --> unop X 3334 if (match(Vec, m_OneUse(m_UnOp(m_VecReverse(m_Value(X)))))) { 3335 auto *OldUnOp = cast<UnaryOperator>(Vec); 3336 auto *NewUnOp = UnaryOperator::CreateWithCopiedFlags( 3337 OldUnOp->getOpcode(), X, OldUnOp, OldUnOp->getName(), 3338 II->getIterator()); 3339 return replaceInstUsesWith(CI, NewUnOp); 3340 } 3341 break; 3342 } 3343 case Intrinsic::vector_reduce_or: 3344 case Intrinsic::vector_reduce_and: { 3345 // Canonicalize logical or/and reductions: 3346 // Or reduction for i1 is represented as: 3347 // %val = bitcast <ReduxWidth x i1> to iReduxWidth 3348 // %res = cmp ne iReduxWidth %val, 0 3349 // And reduction for i1 is represented as: 3350 // %val = bitcast <ReduxWidth x i1> to iReduxWidth 3351 // %res = cmp eq iReduxWidth %val, 11111 3352 Value *Arg = II->getArgOperand(0); 3353 Value *Vect; 3354 3355 if (Value *NewOp = 3356 simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { 3357 replaceUse(II->getOperandUse(0), NewOp); 3358 return II; 3359 } 3360 3361 if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { 3362 if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType())) 3363 if (FTy->getElementType() == Builder.getInt1Ty()) { 3364 Value *Res = Builder.CreateBitCast( 3365 Vect, Builder.getIntNTy(FTy->getNumElements())); 3366 if (IID == Intrinsic::vector_reduce_and) { 3367 Res = Builder.CreateICmpEQ( 3368 Res, ConstantInt::getAllOnesValue(Res->getType())); 3369 } else { 3370 assert(IID == Intrinsic::vector_reduce_or && 3371 "Expected or reduction."); 3372 Res = Builder.CreateIsNotNull(Res); 3373 } 3374 if (Arg != Vect) 3375 Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res, 3376 II->getType()); 3377 return replaceInstUsesWith(CI, Res); 3378 } 3379 } 3380 [[fallthrough]]; 3381 } 3382 case Intrinsic::vector_reduce_add: { 3383 if (IID == Intrinsic::vector_reduce_add) { 3384 // Convert vector_reduce_add(ZExt(<n x i1>)) to 3385 // ZExtOrTrunc(ctpop(bitcast <n x i1> to in)). 3386 // Convert vector_reduce_add(SExt(<n x i1>)) to 3387 // -ZExtOrTrunc(ctpop(bitcast <n x i1> to in)). 3388 // Convert vector_reduce_add(<n x i1>) to 3389 // Trunc(ctpop(bitcast <n x i1> to in)). 3390 Value *Arg = II->getArgOperand(0); 3391 Value *Vect; 3392 3393 if (Value *NewOp = 3394 simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { 3395 replaceUse(II->getOperandUse(0), NewOp); 3396 return II; 3397 } 3398 3399 if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { 3400 if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType())) 3401 if (FTy->getElementType() == Builder.getInt1Ty()) { 3402 Value *V = Builder.CreateBitCast( 3403 Vect, Builder.getIntNTy(FTy->getNumElements())); 3404 Value *Res = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, V); 3405 if (Res->getType() != II->getType()) 3406 Res = Builder.CreateZExtOrTrunc(Res, II->getType()); 3407 if (Arg != Vect && 3408 cast<Instruction>(Arg)->getOpcode() == Instruction::SExt) 3409 Res = Builder.CreateNeg(Res); 3410 return replaceInstUsesWith(CI, Res); 3411 } 3412 } 3413 } 3414 [[fallthrough]]; 3415 } 3416 case Intrinsic::vector_reduce_xor: { 3417 if (IID == Intrinsic::vector_reduce_xor) { 3418 // Exclusive disjunction reduction over the vector with 3419 // (potentially-extended) i1 element type is actually a 3420 // (potentially-extended) arithmetic `add` reduction over the original 3421 // non-extended value: 3422 // vector_reduce_xor(?ext(<n x i1>)) 3423 // --> 3424 // ?ext(vector_reduce_add(<n x i1>)) 3425 Value *Arg = II->getArgOperand(0); 3426 Value *Vect; 3427 3428 if (Value *NewOp = 3429 simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { 3430 replaceUse(II->getOperandUse(0), NewOp); 3431 return II; 3432 } 3433 3434 if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { 3435 if (auto *VTy = dyn_cast<VectorType>(Vect->getType())) 3436 if (VTy->getElementType() == Builder.getInt1Ty()) { 3437 Value *Res = Builder.CreateAddReduce(Vect); 3438 if (Arg != Vect) 3439 Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res, 3440 II->getType()); 3441 return replaceInstUsesWith(CI, Res); 3442 } 3443 } 3444 } 3445 [[fallthrough]]; 3446 } 3447 case Intrinsic::vector_reduce_mul: { 3448 if (IID == Intrinsic::vector_reduce_mul) { 3449 // Multiplicative reduction over the vector with (potentially-extended) 3450 // i1 element type is actually a (potentially zero-extended) 3451 // logical `and` reduction over the original non-extended value: 3452 // vector_reduce_mul(?ext(<n x i1>)) 3453 // --> 3454 // zext(vector_reduce_and(<n x i1>)) 3455 Value *Arg = II->getArgOperand(0); 3456 Value *Vect; 3457 3458 if (Value *NewOp = 3459 simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { 3460 replaceUse(II->getOperandUse(0), NewOp); 3461 return II; 3462 } 3463 3464 if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { 3465 if (auto *VTy = dyn_cast<VectorType>(Vect->getType())) 3466 if (VTy->getElementType() == Builder.getInt1Ty()) { 3467 Value *Res = Builder.CreateAndReduce(Vect); 3468 if (Res->getType() != II->getType()) 3469 Res = Builder.CreateZExt(Res, II->getType()); 3470 return replaceInstUsesWith(CI, Res); 3471 } 3472 } 3473 } 3474 [[fallthrough]]; 3475 } 3476 case Intrinsic::vector_reduce_umin: 3477 case Intrinsic::vector_reduce_umax: { 3478 if (IID == Intrinsic::vector_reduce_umin || 3479 IID == Intrinsic::vector_reduce_umax) { 3480 // UMin/UMax reduction over the vector with (potentially-extended) 3481 // i1 element type is actually a (potentially-extended) 3482 // logical `and`/`or` reduction over the original non-extended value: 3483 // vector_reduce_u{min,max}(?ext(<n x i1>)) 3484 // --> 3485 // ?ext(vector_reduce_{and,or}(<n x i1>)) 3486 Value *Arg = II->getArgOperand(0); 3487 Value *Vect; 3488 3489 if (Value *NewOp = 3490 simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { 3491 replaceUse(II->getOperandUse(0), NewOp); 3492 return II; 3493 } 3494 3495 if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { 3496 if (auto *VTy = dyn_cast<VectorType>(Vect->getType())) 3497 if (VTy->getElementType() == Builder.getInt1Ty()) { 3498 Value *Res = IID == Intrinsic::vector_reduce_umin 3499 ? Builder.CreateAndReduce(Vect) 3500 : Builder.CreateOrReduce(Vect); 3501 if (Arg != Vect) 3502 Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res, 3503 II->getType()); 3504 return replaceInstUsesWith(CI, Res); 3505 } 3506 } 3507 } 3508 [[fallthrough]]; 3509 } 3510 case Intrinsic::vector_reduce_smin: 3511 case Intrinsic::vector_reduce_smax: { 3512 if (IID == Intrinsic::vector_reduce_smin || 3513 IID == Intrinsic::vector_reduce_smax) { 3514 // SMin/SMax reduction over the vector with (potentially-extended) 3515 // i1 element type is actually a (potentially-extended) 3516 // logical `and`/`or` reduction over the original non-extended value: 3517 // vector_reduce_s{min,max}(<n x i1>) 3518 // --> 3519 // vector_reduce_{or,and}(<n x i1>) 3520 // and 3521 // vector_reduce_s{min,max}(sext(<n x i1>)) 3522 // --> 3523 // sext(vector_reduce_{or,and}(<n x i1>)) 3524 // and 3525 // vector_reduce_s{min,max}(zext(<n x i1>)) 3526 // --> 3527 // zext(vector_reduce_{and,or}(<n x i1>)) 3528 Value *Arg = II->getArgOperand(0); 3529 Value *Vect; 3530 3531 if (Value *NewOp = 3532 simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { 3533 replaceUse(II->getOperandUse(0), NewOp); 3534 return II; 3535 } 3536 3537 if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { 3538 if (auto *VTy = dyn_cast<VectorType>(Vect->getType())) 3539 if (VTy->getElementType() == Builder.getInt1Ty()) { 3540 Instruction::CastOps ExtOpc = Instruction::CastOps::CastOpsEnd; 3541 if (Arg != Vect) 3542 ExtOpc = cast<CastInst>(Arg)->getOpcode(); 3543 Value *Res = ((IID == Intrinsic::vector_reduce_smin) == 3544 (ExtOpc == Instruction::CastOps::ZExt)) 3545 ? Builder.CreateAndReduce(Vect) 3546 : Builder.CreateOrReduce(Vect); 3547 if (Arg != Vect) 3548 Res = Builder.CreateCast(ExtOpc, Res, II->getType()); 3549 return replaceInstUsesWith(CI, Res); 3550 } 3551 } 3552 } 3553 [[fallthrough]]; 3554 } 3555 case Intrinsic::vector_reduce_fmax: 3556 case Intrinsic::vector_reduce_fmin: 3557 case Intrinsic::vector_reduce_fadd: 3558 case Intrinsic::vector_reduce_fmul: { 3559 bool CanReorderLanes = (IID != Intrinsic::vector_reduce_fadd && 3560 IID != Intrinsic::vector_reduce_fmul) || 3561 II->hasAllowReassoc(); 3562 const unsigned ArgIdx = (IID == Intrinsic::vector_reduce_fadd || 3563 IID == Intrinsic::vector_reduce_fmul) 3564 ? 1 3565 : 0; 3566 Value *Arg = II->getArgOperand(ArgIdx); 3567 if (Value *NewOp = simplifyReductionOperand(Arg, CanReorderLanes)) { 3568 replaceUse(II->getOperandUse(ArgIdx), NewOp); 3569 return nullptr; 3570 } 3571 break; 3572 } 3573 case Intrinsic::is_fpclass: { 3574 if (Instruction *I = foldIntrinsicIsFPClass(*II)) 3575 return I; 3576 break; 3577 } 3578 case Intrinsic::threadlocal_address: { 3579 Align MinAlign = getKnownAlignment(II->getArgOperand(0), DL, II, &AC, &DT); 3580 MaybeAlign Align = II->getRetAlign(); 3581 if (MinAlign > Align.valueOrOne()) { 3582 II->addRetAttr(Attribute::getWithAlignment(II->getContext(), MinAlign)); 3583 return II; 3584 } 3585 break; 3586 } 3587 default: { 3588 // Handle target specific intrinsics 3589 std::optional<Instruction *> V = targetInstCombineIntrinsic(*II); 3590 if (V) 3591 return *V; 3592 break; 3593 } 3594 } 3595 3596 // Try to fold intrinsic into select operands. This is legal if: 3597 // * The intrinsic is speculatable. 3598 // * The select condition is not a vector, or the intrinsic does not 3599 // perform cross-lane operations. 3600 switch (IID) { 3601 case Intrinsic::ctlz: 3602 case Intrinsic::cttz: 3603 case Intrinsic::ctpop: 3604 case Intrinsic::umin: 3605 case Intrinsic::umax: 3606 case Intrinsic::smin: 3607 case Intrinsic::smax: 3608 case Intrinsic::usub_sat: 3609 case Intrinsic::uadd_sat: 3610 case Intrinsic::ssub_sat: 3611 case Intrinsic::sadd_sat: 3612 for (Value *Op : II->args()) 3613 if (auto *Sel = dyn_cast<SelectInst>(Op)) 3614 if (Instruction *R = FoldOpIntoSelect(*II, Sel)) 3615 return R; 3616 [[fallthrough]]; 3617 default: 3618 break; 3619 } 3620 3621 if (Instruction *Shuf = foldShuffledIntrinsicOperands(II, Builder)) 3622 return Shuf; 3623 3624 // Some intrinsics (like experimental_gc_statepoint) can be used in invoke 3625 // context, so it is handled in visitCallBase and we should trigger it. 3626 return visitCallBase(*II); 3627 } 3628 3629 // Fence instruction simplification 3630 Instruction *InstCombinerImpl::visitFenceInst(FenceInst &FI) { 3631 auto *NFI = dyn_cast<FenceInst>(FI.getNextNonDebugInstruction()); 3632 // This check is solely here to handle arbitrary target-dependent syncscopes. 3633 // TODO: Can remove if does not matter in practice. 3634 if (NFI && FI.isIdenticalTo(NFI)) 3635 return eraseInstFromFunction(FI); 3636 3637 // Returns true if FI1 is identical or stronger fence than FI2. 3638 auto isIdenticalOrStrongerFence = [](FenceInst *FI1, FenceInst *FI2) { 3639 auto FI1SyncScope = FI1->getSyncScopeID(); 3640 // Consider same scope, where scope is global or single-thread. 3641 if (FI1SyncScope != FI2->getSyncScopeID() || 3642 (FI1SyncScope != SyncScope::System && 3643 FI1SyncScope != SyncScope::SingleThread)) 3644 return false; 3645 3646 return isAtLeastOrStrongerThan(FI1->getOrdering(), FI2->getOrdering()); 3647 }; 3648 if (NFI && isIdenticalOrStrongerFence(NFI, &FI)) 3649 return eraseInstFromFunction(FI); 3650 3651 if (auto *PFI = dyn_cast_or_null<FenceInst>(FI.getPrevNonDebugInstruction())) 3652 if (isIdenticalOrStrongerFence(PFI, &FI)) 3653 return eraseInstFromFunction(FI); 3654 return nullptr; 3655 } 3656 3657 // InvokeInst simplification 3658 Instruction *InstCombinerImpl::visitInvokeInst(InvokeInst &II) { 3659 return visitCallBase(II); 3660 } 3661 3662 // CallBrInst simplification 3663 Instruction *InstCombinerImpl::visitCallBrInst(CallBrInst &CBI) { 3664 return visitCallBase(CBI); 3665 } 3666 3667 Instruction *InstCombinerImpl::tryOptimizeCall(CallInst *CI) { 3668 if (!CI->getCalledFunction()) return nullptr; 3669 3670 // Skip optimizing notail and musttail calls so 3671 // LibCallSimplifier::optimizeCall doesn't have to preserve those invariants. 3672 // LibCallSimplifier::optimizeCall should try to preseve tail calls though. 3673 if (CI->isMustTailCall() || CI->isNoTailCall()) 3674 return nullptr; 3675 3676 auto InstCombineRAUW = [this](Instruction *From, Value *With) { 3677 replaceInstUsesWith(*From, With); 3678 }; 3679 auto InstCombineErase = [this](Instruction *I) { 3680 eraseInstFromFunction(*I); 3681 }; 3682 LibCallSimplifier Simplifier(DL, &TLI, &AC, ORE, BFI, PSI, InstCombineRAUW, 3683 InstCombineErase); 3684 if (Value *With = Simplifier.optimizeCall(CI, Builder)) { 3685 ++NumSimplified; 3686 return CI->use_empty() ? CI : replaceInstUsesWith(*CI, With); 3687 } 3688 3689 return nullptr; 3690 } 3691 3692 static IntrinsicInst *findInitTrampolineFromAlloca(Value *TrampMem) { 3693 // Strip off at most one level of pointer casts, looking for an alloca. This 3694 // is good enough in practice and simpler than handling any number of casts. 3695 Value *Underlying = TrampMem->stripPointerCasts(); 3696 if (Underlying != TrampMem && 3697 (!Underlying->hasOneUse() || Underlying->user_back() != TrampMem)) 3698 return nullptr; 3699 if (!isa<AllocaInst>(Underlying)) 3700 return nullptr; 3701 3702 IntrinsicInst *InitTrampoline = nullptr; 3703 for (User *U : TrampMem->users()) { 3704 IntrinsicInst *II = dyn_cast<IntrinsicInst>(U); 3705 if (!II) 3706 return nullptr; 3707 if (II->getIntrinsicID() == Intrinsic::init_trampoline) { 3708 if (InitTrampoline) 3709 // More than one init_trampoline writes to this value. Give up. 3710 return nullptr; 3711 InitTrampoline = II; 3712 continue; 3713 } 3714 if (II->getIntrinsicID() == Intrinsic::adjust_trampoline) 3715 // Allow any number of calls to adjust.trampoline. 3716 continue; 3717 return nullptr; 3718 } 3719 3720 // No call to init.trampoline found. 3721 if (!InitTrampoline) 3722 return nullptr; 3723 3724 // Check that the alloca is being used in the expected way. 3725 if (InitTrampoline->getOperand(0) != TrampMem) 3726 return nullptr; 3727 3728 return InitTrampoline; 3729 } 3730 3731 static IntrinsicInst *findInitTrampolineFromBB(IntrinsicInst *AdjustTramp, 3732 Value *TrampMem) { 3733 // Visit all the previous instructions in the basic block, and try to find a 3734 // init.trampoline which has a direct path to the adjust.trampoline. 3735 for (BasicBlock::iterator I = AdjustTramp->getIterator(), 3736 E = AdjustTramp->getParent()->begin(); 3737 I != E;) { 3738 Instruction *Inst = &*--I; 3739 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) 3740 if (II->getIntrinsicID() == Intrinsic::init_trampoline && 3741 II->getOperand(0) == TrampMem) 3742 return II; 3743 if (Inst->mayWriteToMemory()) 3744 return nullptr; 3745 } 3746 return nullptr; 3747 } 3748 3749 // Given a call to llvm.adjust.trampoline, find and return the corresponding 3750 // call to llvm.init.trampoline if the call to the trampoline can be optimized 3751 // to a direct call to a function. Otherwise return NULL. 3752 static IntrinsicInst *findInitTrampoline(Value *Callee) { 3753 Callee = Callee->stripPointerCasts(); 3754 IntrinsicInst *AdjustTramp = dyn_cast<IntrinsicInst>(Callee); 3755 if (!AdjustTramp || 3756 AdjustTramp->getIntrinsicID() != Intrinsic::adjust_trampoline) 3757 return nullptr; 3758 3759 Value *TrampMem = AdjustTramp->getOperand(0); 3760 3761 if (IntrinsicInst *IT = findInitTrampolineFromAlloca(TrampMem)) 3762 return IT; 3763 if (IntrinsicInst *IT = findInitTrampolineFromBB(AdjustTramp, TrampMem)) 3764 return IT; 3765 return nullptr; 3766 } 3767 3768 bool InstCombinerImpl::annotateAnyAllocSite(CallBase &Call, 3769 const TargetLibraryInfo *TLI) { 3770 // Note: We only handle cases which can't be driven from generic attributes 3771 // here. So, for example, nonnull and noalias (which are common properties 3772 // of some allocation functions) are expected to be handled via annotation 3773 // of the respective allocator declaration with generic attributes. 3774 bool Changed = false; 3775 3776 if (!Call.getType()->isPointerTy()) 3777 return Changed; 3778 3779 std::optional<APInt> Size = getAllocSize(&Call, TLI); 3780 if (Size && *Size != 0) { 3781 // TODO: We really should just emit deref_or_null here and then 3782 // let the generic inference code combine that with nonnull. 3783 if (Call.hasRetAttr(Attribute::NonNull)) { 3784 Changed = !Call.hasRetAttr(Attribute::Dereferenceable); 3785 Call.addRetAttr(Attribute::getWithDereferenceableBytes( 3786 Call.getContext(), Size->getLimitedValue())); 3787 } else { 3788 Changed = !Call.hasRetAttr(Attribute::DereferenceableOrNull); 3789 Call.addRetAttr(Attribute::getWithDereferenceableOrNullBytes( 3790 Call.getContext(), Size->getLimitedValue())); 3791 } 3792 } 3793 3794 // Add alignment attribute if alignment is a power of two constant. 3795 Value *Alignment = getAllocAlignment(&Call, TLI); 3796 if (!Alignment) 3797 return Changed; 3798 3799 ConstantInt *AlignOpC = dyn_cast<ConstantInt>(Alignment); 3800 if (AlignOpC && AlignOpC->getValue().ult(llvm::Value::MaximumAlignment)) { 3801 uint64_t AlignmentVal = AlignOpC->getZExtValue(); 3802 if (llvm::isPowerOf2_64(AlignmentVal)) { 3803 Align ExistingAlign = Call.getRetAlign().valueOrOne(); 3804 Align NewAlign = Align(AlignmentVal); 3805 if (NewAlign > ExistingAlign) { 3806 Call.addRetAttr( 3807 Attribute::getWithAlignment(Call.getContext(), NewAlign)); 3808 Changed = true; 3809 } 3810 } 3811 } 3812 return Changed; 3813 } 3814 3815 /// Improvements for call, callbr and invoke instructions. 3816 Instruction *InstCombinerImpl::visitCallBase(CallBase &Call) { 3817 bool Changed = annotateAnyAllocSite(Call, &TLI); 3818 3819 // Mark any parameters that are known to be non-null with the nonnull 3820 // attribute. This is helpful for inlining calls to functions with null 3821 // checks on their arguments. 3822 SmallVector<unsigned, 4> ArgNos; 3823 unsigned ArgNo = 0; 3824 3825 for (Value *V : Call.args()) { 3826 if (V->getType()->isPointerTy() && 3827 !Call.paramHasAttr(ArgNo, Attribute::NonNull) && 3828 isKnownNonZero(V, getSimplifyQuery().getWithInstruction(&Call))) 3829 ArgNos.push_back(ArgNo); 3830 ArgNo++; 3831 } 3832 3833 assert(ArgNo == Call.arg_size() && "Call arguments not processed correctly."); 3834 3835 if (!ArgNos.empty()) { 3836 AttributeList AS = Call.getAttributes(); 3837 LLVMContext &Ctx = Call.getContext(); 3838 AS = AS.addParamAttribute(Ctx, ArgNos, 3839 Attribute::get(Ctx, Attribute::NonNull)); 3840 Call.setAttributes(AS); 3841 Changed = true; 3842 } 3843 3844 // If the callee is a pointer to a function, attempt to move any casts to the 3845 // arguments of the call/callbr/invoke. 3846 Value *Callee = Call.getCalledOperand(); 3847 Function *CalleeF = dyn_cast<Function>(Callee); 3848 if ((!CalleeF || CalleeF->getFunctionType() != Call.getFunctionType()) && 3849 transformConstExprCastCall(Call)) 3850 return nullptr; 3851 3852 if (CalleeF) { 3853 // Remove the convergent attr on calls when the callee is not convergent. 3854 if (Call.isConvergent() && !CalleeF->isConvergent() && 3855 !CalleeF->isIntrinsic()) { 3856 LLVM_DEBUG(dbgs() << "Removing convergent attr from instr " << Call 3857 << "\n"); 3858 Call.setNotConvergent(); 3859 return &Call; 3860 } 3861 3862 // If the call and callee calling conventions don't match, and neither one 3863 // of the calling conventions is compatible with C calling convention 3864 // this call must be unreachable, as the call is undefined. 3865 if ((CalleeF->getCallingConv() != Call.getCallingConv() && 3866 !(CalleeF->getCallingConv() == llvm::CallingConv::C && 3867 TargetLibraryInfoImpl::isCallingConvCCompatible(&Call)) && 3868 !(Call.getCallingConv() == llvm::CallingConv::C && 3869 TargetLibraryInfoImpl::isCallingConvCCompatible(CalleeF))) && 3870 // Only do this for calls to a function with a body. A prototype may 3871 // not actually end up matching the implementation's calling conv for a 3872 // variety of reasons (e.g. it may be written in assembly). 3873 !CalleeF->isDeclaration()) { 3874 Instruction *OldCall = &Call; 3875 CreateNonTerminatorUnreachable(OldCall); 3876 // If OldCall does not return void then replaceInstUsesWith poison. 3877 // This allows ValueHandlers and custom metadata to adjust itself. 3878 if (!OldCall->getType()->isVoidTy()) 3879 replaceInstUsesWith(*OldCall, PoisonValue::get(OldCall->getType())); 3880 if (isa<CallInst>(OldCall)) 3881 return eraseInstFromFunction(*OldCall); 3882 3883 // We cannot remove an invoke or a callbr, because it would change thexi 3884 // CFG, just change the callee to a null pointer. 3885 cast<CallBase>(OldCall)->setCalledFunction( 3886 CalleeF->getFunctionType(), 3887 Constant::getNullValue(CalleeF->getType())); 3888 return nullptr; 3889 } 3890 } 3891 3892 // Calling a null function pointer is undefined if a null address isn't 3893 // dereferenceable. 3894 if ((isa<ConstantPointerNull>(Callee) && 3895 !NullPointerIsDefined(Call.getFunction())) || 3896 isa<UndefValue>(Callee)) { 3897 // If Call does not return void then replaceInstUsesWith poison. 3898 // This allows ValueHandlers and custom metadata to adjust itself. 3899 if (!Call.getType()->isVoidTy()) 3900 replaceInstUsesWith(Call, PoisonValue::get(Call.getType())); 3901 3902 if (Call.isTerminator()) { 3903 // Can't remove an invoke or callbr because we cannot change the CFG. 3904 return nullptr; 3905 } 3906 3907 // This instruction is not reachable, just remove it. 3908 CreateNonTerminatorUnreachable(&Call); 3909 return eraseInstFromFunction(Call); 3910 } 3911 3912 if (IntrinsicInst *II = findInitTrampoline(Callee)) 3913 return transformCallThroughTrampoline(Call, *II); 3914 3915 if (isa<InlineAsm>(Callee) && !Call.doesNotThrow()) { 3916 InlineAsm *IA = cast<InlineAsm>(Callee); 3917 if (!IA->canThrow()) { 3918 // Normal inline asm calls cannot throw - mark them 3919 // 'nounwind'. 3920 Call.setDoesNotThrow(); 3921 Changed = true; 3922 } 3923 } 3924 3925 // Try to optimize the call if possible, we require DataLayout for most of 3926 // this. None of these calls are seen as possibly dead so go ahead and 3927 // delete the instruction now. 3928 if (CallInst *CI = dyn_cast<CallInst>(&Call)) { 3929 Instruction *I = tryOptimizeCall(CI); 3930 // If we changed something return the result, etc. Otherwise let 3931 // the fallthrough check. 3932 if (I) return eraseInstFromFunction(*I); 3933 } 3934 3935 if (!Call.use_empty() && !Call.isMustTailCall()) 3936 if (Value *ReturnedArg = Call.getReturnedArgOperand()) { 3937 Type *CallTy = Call.getType(); 3938 Type *RetArgTy = ReturnedArg->getType(); 3939 if (RetArgTy->canLosslesslyBitCastTo(CallTy)) 3940 return replaceInstUsesWith( 3941 Call, Builder.CreateBitOrPointerCast(ReturnedArg, CallTy)); 3942 } 3943 3944 // Drop unnecessary kcfi operand bundles from calls that were converted 3945 // into direct calls. 3946 auto Bundle = Call.getOperandBundle(LLVMContext::OB_kcfi); 3947 if (Bundle && !Call.isIndirectCall()) { 3948 DEBUG_WITH_TYPE(DEBUG_TYPE "-kcfi", { 3949 if (CalleeF) { 3950 ConstantInt *FunctionType = nullptr; 3951 ConstantInt *ExpectedType = cast<ConstantInt>(Bundle->Inputs[0]); 3952 3953 if (MDNode *MD = CalleeF->getMetadata(LLVMContext::MD_kcfi_type)) 3954 FunctionType = mdconst::extract<ConstantInt>(MD->getOperand(0)); 3955 3956 if (FunctionType && 3957 FunctionType->getZExtValue() != ExpectedType->getZExtValue()) 3958 dbgs() << Call.getModule()->getName() 3959 << ": warning: kcfi: " << Call.getCaller()->getName() 3960 << ": call to " << CalleeF->getName() 3961 << " using a mismatching function pointer type\n"; 3962 } 3963 }); 3964 3965 return CallBase::removeOperandBundle(&Call, LLVMContext::OB_kcfi); 3966 } 3967 3968 if (isRemovableAlloc(&Call, &TLI)) 3969 return visitAllocSite(Call); 3970 3971 // Handle intrinsics which can be used in both call and invoke context. 3972 switch (Call.getIntrinsicID()) { 3973 case Intrinsic::experimental_gc_statepoint: { 3974 GCStatepointInst &GCSP = *cast<GCStatepointInst>(&Call); 3975 SmallPtrSet<Value *, 32> LiveGcValues; 3976 for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) { 3977 GCRelocateInst &GCR = *const_cast<GCRelocateInst *>(Reloc); 3978 3979 // Remove the relocation if unused. 3980 if (GCR.use_empty()) { 3981 eraseInstFromFunction(GCR); 3982 continue; 3983 } 3984 3985 Value *DerivedPtr = GCR.getDerivedPtr(); 3986 Value *BasePtr = GCR.getBasePtr(); 3987 3988 // Undef is undef, even after relocation. 3989 if (isa<UndefValue>(DerivedPtr) || isa<UndefValue>(BasePtr)) { 3990 replaceInstUsesWith(GCR, UndefValue::get(GCR.getType())); 3991 eraseInstFromFunction(GCR); 3992 continue; 3993 } 3994 3995 if (auto *PT = dyn_cast<PointerType>(GCR.getType())) { 3996 // The relocation of null will be null for most any collector. 3997 // TODO: provide a hook for this in GCStrategy. There might be some 3998 // weird collector this property does not hold for. 3999 if (isa<ConstantPointerNull>(DerivedPtr)) { 4000 // Use null-pointer of gc_relocate's type to replace it. 4001 replaceInstUsesWith(GCR, ConstantPointerNull::get(PT)); 4002 eraseInstFromFunction(GCR); 4003 continue; 4004 } 4005 4006 // isKnownNonNull -> nonnull attribute 4007 if (!GCR.hasRetAttr(Attribute::NonNull) && 4008 isKnownNonZero(DerivedPtr, 4009 getSimplifyQuery().getWithInstruction(&Call))) { 4010 GCR.addRetAttr(Attribute::NonNull); 4011 // We discovered new fact, re-check users. 4012 Worklist.pushUsersToWorkList(GCR); 4013 } 4014 } 4015 4016 // If we have two copies of the same pointer in the statepoint argument 4017 // list, canonicalize to one. This may let us common gc.relocates. 4018 if (GCR.getBasePtr() == GCR.getDerivedPtr() && 4019 GCR.getBasePtrIndex() != GCR.getDerivedPtrIndex()) { 4020 auto *OpIntTy = GCR.getOperand(2)->getType(); 4021 GCR.setOperand(2, ConstantInt::get(OpIntTy, GCR.getBasePtrIndex())); 4022 } 4023 4024 // TODO: bitcast(relocate(p)) -> relocate(bitcast(p)) 4025 // Canonicalize on the type from the uses to the defs 4026 4027 // TODO: relocate((gep p, C, C2, ...)) -> gep(relocate(p), C, C2, ...) 4028 LiveGcValues.insert(BasePtr); 4029 LiveGcValues.insert(DerivedPtr); 4030 } 4031 std::optional<OperandBundleUse> Bundle = 4032 GCSP.getOperandBundle(LLVMContext::OB_gc_live); 4033 unsigned NumOfGCLives = LiveGcValues.size(); 4034 if (!Bundle || NumOfGCLives == Bundle->Inputs.size()) 4035 break; 4036 // We can reduce the size of gc live bundle. 4037 DenseMap<Value *, unsigned> Val2Idx; 4038 std::vector<Value *> NewLiveGc; 4039 for (Value *V : Bundle->Inputs) { 4040 if (Val2Idx.count(V)) 4041 continue; 4042 if (LiveGcValues.count(V)) { 4043 Val2Idx[V] = NewLiveGc.size(); 4044 NewLiveGc.push_back(V); 4045 } else 4046 Val2Idx[V] = NumOfGCLives; 4047 } 4048 // Update all gc.relocates 4049 for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) { 4050 GCRelocateInst &GCR = *const_cast<GCRelocateInst *>(Reloc); 4051 Value *BasePtr = GCR.getBasePtr(); 4052 assert(Val2Idx.count(BasePtr) && Val2Idx[BasePtr] != NumOfGCLives && 4053 "Missed live gc for base pointer"); 4054 auto *OpIntTy1 = GCR.getOperand(1)->getType(); 4055 GCR.setOperand(1, ConstantInt::get(OpIntTy1, Val2Idx[BasePtr])); 4056 Value *DerivedPtr = GCR.getDerivedPtr(); 4057 assert(Val2Idx.count(DerivedPtr) && Val2Idx[DerivedPtr] != NumOfGCLives && 4058 "Missed live gc for derived pointer"); 4059 auto *OpIntTy2 = GCR.getOperand(2)->getType(); 4060 GCR.setOperand(2, ConstantInt::get(OpIntTy2, Val2Idx[DerivedPtr])); 4061 } 4062 // Create new statepoint instruction. 4063 OperandBundleDef NewBundle("gc-live", NewLiveGc); 4064 return CallBase::Create(&Call, NewBundle); 4065 } 4066 default: { break; } 4067 } 4068 4069 return Changed ? &Call : nullptr; 4070 } 4071 4072 /// If the callee is a constexpr cast of a function, attempt to move the cast to 4073 /// the arguments of the call/invoke. 4074 /// CallBrInst is not supported. 4075 bool InstCombinerImpl::transformConstExprCastCall(CallBase &Call) { 4076 auto *Callee = 4077 dyn_cast<Function>(Call.getCalledOperand()->stripPointerCasts()); 4078 if (!Callee) 4079 return false; 4080 4081 assert(!isa<CallBrInst>(Call) && 4082 "CallBr's don't have a single point after a def to insert at"); 4083 4084 // If this is a call to a thunk function, don't remove the cast. Thunks are 4085 // used to transparently forward all incoming parameters and outgoing return 4086 // values, so it's important to leave the cast in place. 4087 if (Callee->hasFnAttribute("thunk")) 4088 return false; 4089 4090 // If this is a call to a naked function, the assembly might be 4091 // using an argument, or otherwise rely on the frame layout, 4092 // the function prototype will mismatch. 4093 if (Callee->hasFnAttribute(Attribute::Naked)) 4094 return false; 4095 4096 // If this is a musttail call, the callee's prototype must match the caller's 4097 // prototype with the exception of pointee types. The code below doesn't 4098 // implement that, so we can't do this transform. 4099 // TODO: Do the transform if it only requires adding pointer casts. 4100 if (Call.isMustTailCall()) 4101 return false; 4102 4103 Instruction *Caller = &Call; 4104 const AttributeList &CallerPAL = Call.getAttributes(); 4105 4106 // Okay, this is a cast from a function to a different type. Unless doing so 4107 // would cause a type conversion of one of our arguments, change this call to 4108 // be a direct call with arguments casted to the appropriate types. 4109 FunctionType *FT = Callee->getFunctionType(); 4110 Type *OldRetTy = Caller->getType(); 4111 Type *NewRetTy = FT->getReturnType(); 4112 4113 // Check to see if we are changing the return type... 4114 if (OldRetTy != NewRetTy) { 4115 4116 if (NewRetTy->isStructTy()) 4117 return false; // TODO: Handle multiple return values. 4118 4119 if (!CastInst::isBitOrNoopPointerCastable(NewRetTy, OldRetTy, DL)) { 4120 if (Callee->isDeclaration()) 4121 return false; // Cannot transform this return value. 4122 4123 if (!Caller->use_empty() && 4124 // void -> non-void is handled specially 4125 !NewRetTy->isVoidTy()) 4126 return false; // Cannot transform this return value. 4127 } 4128 4129 if (!CallerPAL.isEmpty() && !Caller->use_empty()) { 4130 AttrBuilder RAttrs(FT->getContext(), CallerPAL.getRetAttrs()); 4131 if (RAttrs.overlaps(AttributeFuncs::typeIncompatible(NewRetTy))) 4132 return false; // Attribute not compatible with transformed value. 4133 } 4134 4135 // If the callbase is an invoke instruction, and the return value is 4136 // used by a PHI node in a successor, we cannot change the return type of 4137 // the call because there is no place to put the cast instruction (without 4138 // breaking the critical edge). Bail out in this case. 4139 if (!Caller->use_empty()) { 4140 BasicBlock *PhisNotSupportedBlock = nullptr; 4141 if (auto *II = dyn_cast<InvokeInst>(Caller)) 4142 PhisNotSupportedBlock = II->getNormalDest(); 4143 if (PhisNotSupportedBlock) 4144 for (User *U : Caller->users()) 4145 if (PHINode *PN = dyn_cast<PHINode>(U)) 4146 if (PN->getParent() == PhisNotSupportedBlock) 4147 return false; 4148 } 4149 } 4150 4151 unsigned NumActualArgs = Call.arg_size(); 4152 unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); 4153 4154 // Prevent us turning: 4155 // declare void @takes_i32_inalloca(i32* inalloca) 4156 // call void bitcast (void (i32*)* @takes_i32_inalloca to void (i32)*)(i32 0) 4157 // 4158 // into: 4159 // call void @takes_i32_inalloca(i32* null) 4160 // 4161 // Similarly, avoid folding away bitcasts of byval calls. 4162 if (Callee->getAttributes().hasAttrSomewhere(Attribute::InAlloca) || 4163 Callee->getAttributes().hasAttrSomewhere(Attribute::Preallocated)) 4164 return false; 4165 4166 auto AI = Call.arg_begin(); 4167 for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { 4168 Type *ParamTy = FT->getParamType(i); 4169 Type *ActTy = (*AI)->getType(); 4170 4171 if (!CastInst::isBitOrNoopPointerCastable(ActTy, ParamTy, DL)) 4172 return false; // Cannot transform this parameter value. 4173 4174 // Check if there are any incompatible attributes we cannot drop safely. 4175 if (AttrBuilder(FT->getContext(), CallerPAL.getParamAttrs(i)) 4176 .overlaps(AttributeFuncs::typeIncompatible( 4177 ParamTy, AttributeFuncs::ASK_UNSAFE_TO_DROP))) 4178 return false; // Attribute not compatible with transformed value. 4179 4180 if (Call.isInAllocaArgument(i) || 4181 CallerPAL.hasParamAttr(i, Attribute::Preallocated)) 4182 return false; // Cannot transform to and from inalloca/preallocated. 4183 4184 if (CallerPAL.hasParamAttr(i, Attribute::SwiftError)) 4185 return false; 4186 4187 if (CallerPAL.hasParamAttr(i, Attribute::ByVal) != 4188 Callee->getAttributes().hasParamAttr(i, Attribute::ByVal)) 4189 return false; // Cannot transform to or from byval. 4190 } 4191 4192 if (Callee->isDeclaration()) { 4193 // Do not delete arguments unless we have a function body. 4194 if (FT->getNumParams() < NumActualArgs && !FT->isVarArg()) 4195 return false; 4196 4197 // If the callee is just a declaration, don't change the varargsness of the 4198 // call. We don't want to introduce a varargs call where one doesn't 4199 // already exist. 4200 if (FT->isVarArg() != Call.getFunctionType()->isVarArg()) 4201 return false; 4202 4203 // If both the callee and the cast type are varargs, we still have to make 4204 // sure the number of fixed parameters are the same or we have the same 4205 // ABI issues as if we introduce a varargs call. 4206 if (FT->isVarArg() && Call.getFunctionType()->isVarArg() && 4207 FT->getNumParams() != Call.getFunctionType()->getNumParams()) 4208 return false; 4209 } 4210 4211 if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && 4212 !CallerPAL.isEmpty()) { 4213 // In this case we have more arguments than the new function type, but we 4214 // won't be dropping them. Check that these extra arguments have attributes 4215 // that are compatible with being a vararg call argument. 4216 unsigned SRetIdx; 4217 if (CallerPAL.hasAttrSomewhere(Attribute::StructRet, &SRetIdx) && 4218 SRetIdx - AttributeList::FirstArgIndex >= FT->getNumParams()) 4219 return false; 4220 } 4221 4222 // Okay, we decided that this is a safe thing to do: go ahead and start 4223 // inserting cast instructions as necessary. 4224 SmallVector<Value *, 8> Args; 4225 SmallVector<AttributeSet, 8> ArgAttrs; 4226 Args.reserve(NumActualArgs); 4227 ArgAttrs.reserve(NumActualArgs); 4228 4229 // Get any return attributes. 4230 AttrBuilder RAttrs(FT->getContext(), CallerPAL.getRetAttrs()); 4231 4232 // If the return value is not being used, the type may not be compatible 4233 // with the existing attributes. Wipe out any problematic attributes. 4234 RAttrs.remove(AttributeFuncs::typeIncompatible(NewRetTy)); 4235 4236 LLVMContext &Ctx = Call.getContext(); 4237 AI = Call.arg_begin(); 4238 for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { 4239 Type *ParamTy = FT->getParamType(i); 4240 4241 Value *NewArg = *AI; 4242 if ((*AI)->getType() != ParamTy) 4243 NewArg = Builder.CreateBitOrPointerCast(*AI, ParamTy); 4244 Args.push_back(NewArg); 4245 4246 // Add any parameter attributes except the ones incompatible with the new 4247 // type. Note that we made sure all incompatible ones are safe to drop. 4248 AttributeMask IncompatibleAttrs = AttributeFuncs::typeIncompatible( 4249 ParamTy, AttributeFuncs::ASK_SAFE_TO_DROP); 4250 ArgAttrs.push_back( 4251 CallerPAL.getParamAttrs(i).removeAttributes(Ctx, IncompatibleAttrs)); 4252 } 4253 4254 // If the function takes more arguments than the call was taking, add them 4255 // now. 4256 for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) { 4257 Args.push_back(Constant::getNullValue(FT->getParamType(i))); 4258 ArgAttrs.push_back(AttributeSet()); 4259 } 4260 4261 // If we are removing arguments to the function, emit an obnoxious warning. 4262 if (FT->getNumParams() < NumActualArgs) { 4263 // TODO: if (!FT->isVarArg()) this call may be unreachable. PR14722 4264 if (FT->isVarArg()) { 4265 // Add all of the arguments in their promoted form to the arg list. 4266 for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { 4267 Type *PTy = getPromotedType((*AI)->getType()); 4268 Value *NewArg = *AI; 4269 if (PTy != (*AI)->getType()) { 4270 // Must promote to pass through va_arg area! 4271 Instruction::CastOps opcode = 4272 CastInst::getCastOpcode(*AI, false, PTy, false); 4273 NewArg = Builder.CreateCast(opcode, *AI, PTy); 4274 } 4275 Args.push_back(NewArg); 4276 4277 // Add any parameter attributes. 4278 ArgAttrs.push_back(CallerPAL.getParamAttrs(i)); 4279 } 4280 } 4281 } 4282 4283 AttributeSet FnAttrs = CallerPAL.getFnAttrs(); 4284 4285 if (NewRetTy->isVoidTy()) 4286 Caller->setName(""); // Void type should not have a name. 4287 4288 assert((ArgAttrs.size() == FT->getNumParams() || FT->isVarArg()) && 4289 "missing argument attributes"); 4290 AttributeList NewCallerPAL = AttributeList::get( 4291 Ctx, FnAttrs, AttributeSet::get(Ctx, RAttrs), ArgAttrs); 4292 4293 SmallVector<OperandBundleDef, 1> OpBundles; 4294 Call.getOperandBundlesAsDefs(OpBundles); 4295 4296 CallBase *NewCall; 4297 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 4298 NewCall = Builder.CreateInvoke(Callee, II->getNormalDest(), 4299 II->getUnwindDest(), Args, OpBundles); 4300 } else { 4301 NewCall = Builder.CreateCall(Callee, Args, OpBundles); 4302 cast<CallInst>(NewCall)->setTailCallKind( 4303 cast<CallInst>(Caller)->getTailCallKind()); 4304 } 4305 NewCall->takeName(Caller); 4306 NewCall->setCallingConv(Call.getCallingConv()); 4307 NewCall->setAttributes(NewCallerPAL); 4308 4309 // Preserve prof metadata if any. 4310 NewCall->copyMetadata(*Caller, {LLVMContext::MD_prof}); 4311 4312 // Insert a cast of the return type as necessary. 4313 Instruction *NC = NewCall; 4314 Value *NV = NC; 4315 if (OldRetTy != NV->getType() && !Caller->use_empty()) { 4316 if (!NV->getType()->isVoidTy()) { 4317 NV = NC = CastInst::CreateBitOrPointerCast(NC, OldRetTy); 4318 NC->setDebugLoc(Caller->getDebugLoc()); 4319 4320 auto OptInsertPt = NewCall->getInsertionPointAfterDef(); 4321 assert(OptInsertPt && "No place to insert cast"); 4322 InsertNewInstBefore(NC, *OptInsertPt); 4323 Worklist.pushUsersToWorkList(*Caller); 4324 } else { 4325 NV = PoisonValue::get(Caller->getType()); 4326 } 4327 } 4328 4329 if (!Caller->use_empty()) 4330 replaceInstUsesWith(*Caller, NV); 4331 else if (Caller->hasValueHandle()) { 4332 if (OldRetTy == NV->getType()) 4333 ValueHandleBase::ValueIsRAUWd(Caller, NV); 4334 else 4335 // We cannot call ValueIsRAUWd with a different type, and the 4336 // actual tracked value will disappear. 4337 ValueHandleBase::ValueIsDeleted(Caller); 4338 } 4339 4340 eraseInstFromFunction(*Caller); 4341 return true; 4342 } 4343 4344 /// Turn a call to a function created by init_trampoline / adjust_trampoline 4345 /// intrinsic pair into a direct call to the underlying function. 4346 Instruction * 4347 InstCombinerImpl::transformCallThroughTrampoline(CallBase &Call, 4348 IntrinsicInst &Tramp) { 4349 FunctionType *FTy = Call.getFunctionType(); 4350 AttributeList Attrs = Call.getAttributes(); 4351 4352 // If the call already has the 'nest' attribute somewhere then give up - 4353 // otherwise 'nest' would occur twice after splicing in the chain. 4354 if (Attrs.hasAttrSomewhere(Attribute::Nest)) 4355 return nullptr; 4356 4357 Function *NestF = cast<Function>(Tramp.getArgOperand(1)->stripPointerCasts()); 4358 FunctionType *NestFTy = NestF->getFunctionType(); 4359 4360 AttributeList NestAttrs = NestF->getAttributes(); 4361 if (!NestAttrs.isEmpty()) { 4362 unsigned NestArgNo = 0; 4363 Type *NestTy = nullptr; 4364 AttributeSet NestAttr; 4365 4366 // Look for a parameter marked with the 'nest' attribute. 4367 for (FunctionType::param_iterator I = NestFTy->param_begin(), 4368 E = NestFTy->param_end(); 4369 I != E; ++NestArgNo, ++I) { 4370 AttributeSet AS = NestAttrs.getParamAttrs(NestArgNo); 4371 if (AS.hasAttribute(Attribute::Nest)) { 4372 // Record the parameter type and any other attributes. 4373 NestTy = *I; 4374 NestAttr = AS; 4375 break; 4376 } 4377 } 4378 4379 if (NestTy) { 4380 std::vector<Value*> NewArgs; 4381 std::vector<AttributeSet> NewArgAttrs; 4382 NewArgs.reserve(Call.arg_size() + 1); 4383 NewArgAttrs.reserve(Call.arg_size()); 4384 4385 // Insert the nest argument into the call argument list, which may 4386 // mean appending it. Likewise for attributes. 4387 4388 { 4389 unsigned ArgNo = 0; 4390 auto I = Call.arg_begin(), E = Call.arg_end(); 4391 do { 4392 if (ArgNo == NestArgNo) { 4393 // Add the chain argument and attributes. 4394 Value *NestVal = Tramp.getArgOperand(2); 4395 if (NestVal->getType() != NestTy) 4396 NestVal = Builder.CreateBitCast(NestVal, NestTy, "nest"); 4397 NewArgs.push_back(NestVal); 4398 NewArgAttrs.push_back(NestAttr); 4399 } 4400 4401 if (I == E) 4402 break; 4403 4404 // Add the original argument and attributes. 4405 NewArgs.push_back(*I); 4406 NewArgAttrs.push_back(Attrs.getParamAttrs(ArgNo)); 4407 4408 ++ArgNo; 4409 ++I; 4410 } while (true); 4411 } 4412 4413 // The trampoline may have been bitcast to a bogus type (FTy). 4414 // Handle this by synthesizing a new function type, equal to FTy 4415 // with the chain parameter inserted. 4416 4417 std::vector<Type*> NewTypes; 4418 NewTypes.reserve(FTy->getNumParams()+1); 4419 4420 // Insert the chain's type into the list of parameter types, which may 4421 // mean appending it. 4422 { 4423 unsigned ArgNo = 0; 4424 FunctionType::param_iterator I = FTy->param_begin(), 4425 E = FTy->param_end(); 4426 4427 do { 4428 if (ArgNo == NestArgNo) 4429 // Add the chain's type. 4430 NewTypes.push_back(NestTy); 4431 4432 if (I == E) 4433 break; 4434 4435 // Add the original type. 4436 NewTypes.push_back(*I); 4437 4438 ++ArgNo; 4439 ++I; 4440 } while (true); 4441 } 4442 4443 // Replace the trampoline call with a direct call. Let the generic 4444 // code sort out any function type mismatches. 4445 FunctionType *NewFTy = 4446 FunctionType::get(FTy->getReturnType(), NewTypes, FTy->isVarArg()); 4447 AttributeList NewPAL = 4448 AttributeList::get(FTy->getContext(), Attrs.getFnAttrs(), 4449 Attrs.getRetAttrs(), NewArgAttrs); 4450 4451 SmallVector<OperandBundleDef, 1> OpBundles; 4452 Call.getOperandBundlesAsDefs(OpBundles); 4453 4454 Instruction *NewCaller; 4455 if (InvokeInst *II = dyn_cast<InvokeInst>(&Call)) { 4456 NewCaller = InvokeInst::Create(NewFTy, NestF, II->getNormalDest(), 4457 II->getUnwindDest(), NewArgs, OpBundles); 4458 cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv()); 4459 cast<InvokeInst>(NewCaller)->setAttributes(NewPAL); 4460 } else if (CallBrInst *CBI = dyn_cast<CallBrInst>(&Call)) { 4461 NewCaller = 4462 CallBrInst::Create(NewFTy, NestF, CBI->getDefaultDest(), 4463 CBI->getIndirectDests(), NewArgs, OpBundles); 4464 cast<CallBrInst>(NewCaller)->setCallingConv(CBI->getCallingConv()); 4465 cast<CallBrInst>(NewCaller)->setAttributes(NewPAL); 4466 } else { 4467 NewCaller = CallInst::Create(NewFTy, NestF, NewArgs, OpBundles); 4468 cast<CallInst>(NewCaller)->setTailCallKind( 4469 cast<CallInst>(Call).getTailCallKind()); 4470 cast<CallInst>(NewCaller)->setCallingConv( 4471 cast<CallInst>(Call).getCallingConv()); 4472 cast<CallInst>(NewCaller)->setAttributes(NewPAL); 4473 } 4474 NewCaller->setDebugLoc(Call.getDebugLoc()); 4475 4476 return NewCaller; 4477 } 4478 } 4479 4480 // Replace the trampoline call with a direct call. Since there is no 'nest' 4481 // parameter, there is no need to adjust the argument list. Let the generic 4482 // code sort out any function type mismatches. 4483 Call.setCalledFunction(FTy, NestF); 4484 return &Call; 4485 } 4486