//===- InstCombineCalls.cpp -----------------------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This file implements the visitCall, visitInvoke, and visitCallBr functions. // //===----------------------------------------------------------------------===// #include "InstCombineInternal.h" #include "llvm/ADT/APFloat.h" #include "llvm/ADT/APInt.h" #include "llvm/ADT/APSInt.h" #include "llvm/ADT/ArrayRef.h" #include "llvm/ADT/STLFunctionalExtras.h" #include "llvm/ADT/SmallBitVector.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/Statistic.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/AssumeBundleQueries.h" #include "llvm/Analysis/AssumptionCache.h" #include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Analysis/Loads.h" #include "llvm/Analysis/MemoryBuiltins.h" #include "llvm/Analysis/ValueTracking.h" #include "llvm/Analysis/VectorUtils.h" #include "llvm/IR/AttributeMask.h" #include "llvm/IR/Attributes.h" #include "llvm/IR/BasicBlock.h" #include "llvm/IR/Constant.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/DebugInfo.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/Function.h" #include "llvm/IR/GlobalVariable.h" #include "llvm/IR/InlineAsm.h" #include "llvm/IR/InstrTypes.h" #include "llvm/IR/Instruction.h" #include "llvm/IR/Instructions.h" #include "llvm/IR/IntrinsicInst.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/IntrinsicsAArch64.h" #include "llvm/IR/IntrinsicsAMDGPU.h" #include "llvm/IR/IntrinsicsARM.h" #include "llvm/IR/IntrinsicsHexagon.h" #include "llvm/IR/LLVMContext.h" #include "llvm/IR/Metadata.h" #include "llvm/IR/PatternMatch.h" #include "llvm/IR/Statepoint.h" #include "llvm/IR/Type.h" #include "llvm/IR/User.h" #include "llvm/IR/Value.h" #include "llvm/IR/ValueHandle.h" #include "llvm/Support/AtomicOrdering.h" #include "llvm/Support/Casting.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Compiler.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/KnownBits.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Transforms/InstCombine/InstCombiner.h" #include "llvm/Transforms/Utils/AssumeBundleBuilder.h" #include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Utils/SimplifyLibCalls.h" #include #include #include #include #include #include #define DEBUG_TYPE "instcombine" #include "llvm/Transforms/Utils/InstructionWorklist.h" using namespace llvm; using namespace PatternMatch; STATISTIC(NumSimplified, "Number of library calls simplified"); static cl::opt GuardWideningWindow( "instcombine-guard-widening-window", cl::init(3), cl::desc("How wide an instruction window to bypass looking for " "another guard")); /// Return the specified type promoted as it would be to pass though a va_arg /// area. static Type *getPromotedType(Type *Ty) { if (IntegerType* ITy = dyn_cast(Ty)) { if (ITy->getBitWidth() < 32) return Type::getInt32Ty(Ty->getContext()); } return Ty; } /// Recognize a memcpy/memmove from a trivially otherwise unused alloca. /// TODO: This should probably be integrated with visitAllocSites, but that /// requires a deeper change to allow either unread or unwritten objects. static bool hasUndefSource(AnyMemTransferInst *MI) { auto *Src = MI->getRawSource(); while (isa(Src) || isa(Src)) { if (!Src->hasOneUse()) return false; Src = cast(Src)->getOperand(0); } return isa(Src) && Src->hasOneUse(); } Instruction *InstCombinerImpl::SimplifyAnyMemTransfer(AnyMemTransferInst *MI) { Align DstAlign = getKnownAlignment(MI->getRawDest(), DL, MI, &AC, &DT); MaybeAlign CopyDstAlign = MI->getDestAlign(); if (!CopyDstAlign || *CopyDstAlign < DstAlign) { MI->setDestAlignment(DstAlign); return MI; } Align SrcAlign = getKnownAlignment(MI->getRawSource(), DL, MI, &AC, &DT); MaybeAlign CopySrcAlign = MI->getSourceAlign(); if (!CopySrcAlign || *CopySrcAlign < SrcAlign) { MI->setSourceAlignment(SrcAlign); return MI; } // If we have a store to a location which is known constant, we can conclude // that the store must be storing the constant value (else the memory // wouldn't be constant), and this must be a noop. if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) { // Set the size of the copy to 0, it will be deleted on the next iteration. MI->setLength(Constant::getNullValue(MI->getLength()->getType())); return MI; } // If the source is provably undef, the memcpy/memmove doesn't do anything // (unless the transfer is volatile). if (hasUndefSource(MI) && !MI->isVolatile()) { // Set the size of the copy to 0, it will be deleted on the next iteration. MI->setLength(Constant::getNullValue(MI->getLength()->getType())); return MI; } // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with // load/store. ConstantInt *MemOpLength = dyn_cast(MI->getLength()); if (!MemOpLength) return nullptr; // Source and destination pointer types are always "i8*" for intrinsic. See // if the size is something we can handle with a single primitive load/store. // A single load+store correctly handles overlapping memory in the memmove // case. uint64_t Size = MemOpLength->getLimitedValue(); assert(Size && "0-sized memory transferring should be removed already."); if (Size > 8 || (Size&(Size-1))) return nullptr; // If not 1/2/4/8 bytes, exit. // If it is an atomic and alignment is less than the size then we will // introduce the unaligned memory access which will be later transformed // into libcall in CodeGen. This is not evident performance gain so disable // it now. if (isa(MI)) if (*CopyDstAlign < Size || *CopySrcAlign < Size) return nullptr; // Use an integer load+store unless we can find something better. IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3); // If the memcpy has metadata describing the members, see if we can get the // TBAA, scope and noalias tags describing our copy. AAMDNodes AACopyMD = MI->getAAMetadata().adjustForAccess(Size); Value *Src = MI->getArgOperand(1); Value *Dest = MI->getArgOperand(0); LoadInst *L = Builder.CreateLoad(IntType, Src); // Alignment from the mem intrinsic will be better, so use it. L->setAlignment(*CopySrcAlign); L->setAAMetadata(AACopyMD); MDNode *LoopMemParallelMD = MI->getMetadata(LLVMContext::MD_mem_parallel_loop_access); if (LoopMemParallelMD) L->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD); MDNode *AccessGroupMD = MI->getMetadata(LLVMContext::MD_access_group); if (AccessGroupMD) L->setMetadata(LLVMContext::MD_access_group, AccessGroupMD); StoreInst *S = Builder.CreateStore(L, Dest); // Alignment from the mem intrinsic will be better, so use it. S->setAlignment(*CopyDstAlign); S->setAAMetadata(AACopyMD); if (LoopMemParallelMD) S->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD); if (AccessGroupMD) S->setMetadata(LLVMContext::MD_access_group, AccessGroupMD); S->copyMetadata(*MI, LLVMContext::MD_DIAssignID); if (auto *MT = dyn_cast(MI)) { // non-atomics can be volatile L->setVolatile(MT->isVolatile()); S->setVolatile(MT->isVolatile()); } if (isa(MI)) { // atomics have to be unordered L->setOrdering(AtomicOrdering::Unordered); S->setOrdering(AtomicOrdering::Unordered); } // Set the size of the copy to 0, it will be deleted on the next iteration. MI->setLength(Constant::getNullValue(MemOpLength->getType())); return MI; } Instruction *InstCombinerImpl::SimplifyAnyMemSet(AnyMemSetInst *MI) { const Align KnownAlignment = getKnownAlignment(MI->getDest(), DL, MI, &AC, &DT); MaybeAlign MemSetAlign = MI->getDestAlign(); if (!MemSetAlign || *MemSetAlign < KnownAlignment) { MI->setDestAlignment(KnownAlignment); return MI; } // If we have a store to a location which is known constant, we can conclude // that the store must be storing the constant value (else the memory // wouldn't be constant), and this must be a noop. if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) { // Set the size of the copy to 0, it will be deleted on the next iteration. MI->setLength(Constant::getNullValue(MI->getLength()->getType())); return MI; } // Remove memset with an undef value. // FIXME: This is technically incorrect because it might overwrite a poison // value. Change to PoisonValue once #52930 is resolved. if (isa(MI->getValue())) { // Set the size of the copy to 0, it will be deleted on the next iteration. MI->setLength(Constant::getNullValue(MI->getLength()->getType())); return MI; } // Extract the length and alignment and fill if they are constant. ConstantInt *LenC = dyn_cast(MI->getLength()); ConstantInt *FillC = dyn_cast(MI->getValue()); if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8)) return nullptr; const uint64_t Len = LenC->getLimitedValue(); assert(Len && "0-sized memory setting should be removed already."); const Align Alignment = MI->getDestAlign().valueOrOne(); // If it is an atomic and alignment is less than the size then we will // introduce the unaligned memory access which will be later transformed // into libcall in CodeGen. This is not evident performance gain so disable // it now. if (isa(MI)) if (Alignment < Len) return nullptr; // memset(s,c,n) -> store s, c (for n=1,2,4,8) if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) { Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8. Value *Dest = MI->getDest(); // Extract the fill value and store. const uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL; Constant *FillVal = ConstantInt::get(ITy, Fill); StoreInst *S = Builder.CreateStore(FillVal, Dest, MI->isVolatile()); S->copyMetadata(*MI, LLVMContext::MD_DIAssignID); auto replaceOpForAssignmentMarkers = [FillC, FillVal](auto *DbgAssign) { if (llvm::is_contained(DbgAssign->location_ops(), FillC)) DbgAssign->replaceVariableLocationOp(FillC, FillVal); }; for_each(at::getAssignmentMarkers(S), replaceOpForAssignmentMarkers); for_each(at::getDVRAssignmentMarkers(S), replaceOpForAssignmentMarkers); S->setAlignment(Alignment); if (isa(MI)) S->setOrdering(AtomicOrdering::Unordered); // Set the size of the copy to 0, it will be deleted on the next iteration. MI->setLength(Constant::getNullValue(LenC->getType())); return MI; } return nullptr; } // TODO, Obvious Missing Transforms: // * Narrow width by halfs excluding zero/undef lanes Value *InstCombinerImpl::simplifyMaskedLoad(IntrinsicInst &II) { Value *LoadPtr = II.getArgOperand(0); const Align Alignment = cast(II.getArgOperand(1))->getAlignValue(); // If the mask is all ones or undefs, this is a plain vector load of the 1st // argument. if (maskIsAllOneOrUndef(II.getArgOperand(2))) { LoadInst *L = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment, "unmaskedload"); L->copyMetadata(II); return L; } // If we can unconditionally load from this address, replace with a // load/select idiom. TODO: use DT for context sensitive query if (isDereferenceablePointer(LoadPtr, II.getType(), II.getDataLayout(), &II, &AC)) { LoadInst *LI = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment, "unmaskedload"); LI->copyMetadata(II); return Builder.CreateSelect(II.getArgOperand(2), LI, II.getArgOperand(3)); } return nullptr; } // TODO, Obvious Missing Transforms: // * Single constant active lane -> store // * Narrow width by halfs excluding zero/undef lanes Instruction *InstCombinerImpl::simplifyMaskedStore(IntrinsicInst &II) { auto *ConstMask = dyn_cast(II.getArgOperand(3)); if (!ConstMask) return nullptr; // If the mask is all zeros, this instruction does nothing. if (ConstMask->isNullValue()) return eraseInstFromFunction(II); // If the mask is all ones, this is a plain vector store of the 1st argument. if (ConstMask->isAllOnesValue()) { Value *StorePtr = II.getArgOperand(1); Align Alignment = cast(II.getArgOperand(2))->getAlignValue(); StoreInst *S = new StoreInst(II.getArgOperand(0), StorePtr, false, Alignment); S->copyMetadata(II); return S; } if (isa(ConstMask->getType())) return nullptr; // Use masked off lanes to simplify operands via SimplifyDemandedVectorElts APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask); APInt PoisonElts(DemandedElts.getBitWidth(), 0); if (Value *V = SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts, PoisonElts)) return replaceOperand(II, 0, V); return nullptr; } // TODO, Obvious Missing Transforms: // * Single constant active lane load -> load // * Dereferenceable address & few lanes -> scalarize speculative load/selects // * Adjacent vector addresses -> masked.load // * Narrow width by halfs excluding zero/undef lanes // * Vector incrementing address -> vector masked load Instruction *InstCombinerImpl::simplifyMaskedGather(IntrinsicInst &II) { auto *ConstMask = dyn_cast(II.getArgOperand(2)); if (!ConstMask) return nullptr; // Vector splat address w/known mask -> scalar load // Fold the gather to load the source vector first lane // because it is reloading the same value each time if (ConstMask->isAllOnesValue()) if (auto *SplatPtr = getSplatValue(II.getArgOperand(0))) { auto *VecTy = cast(II.getType()); const Align Alignment = cast(II.getArgOperand(1))->getAlignValue(); LoadInst *L = Builder.CreateAlignedLoad(VecTy->getElementType(), SplatPtr, Alignment, "load.scalar"); Value *Shuf = Builder.CreateVectorSplat(VecTy->getElementCount(), L, "broadcast"); return replaceInstUsesWith(II, cast(Shuf)); } return nullptr; } // TODO, Obvious Missing Transforms: // * Single constant active lane -> store // * Adjacent vector addresses -> masked.store // * Narrow store width by halfs excluding zero/undef lanes // * Vector incrementing address -> vector masked store Instruction *InstCombinerImpl::simplifyMaskedScatter(IntrinsicInst &II) { auto *ConstMask = dyn_cast(II.getArgOperand(3)); if (!ConstMask) return nullptr; // If the mask is all zeros, a scatter does nothing. if (ConstMask->isNullValue()) return eraseInstFromFunction(II); // Vector splat address -> scalar store if (auto *SplatPtr = getSplatValue(II.getArgOperand(1))) { // scatter(splat(value), splat(ptr), non-zero-mask) -> store value, ptr if (auto *SplatValue = getSplatValue(II.getArgOperand(0))) { if (maskContainsAllOneOrUndef(ConstMask)) { Align Alignment = cast(II.getArgOperand(2))->getAlignValue(); StoreInst *S = new StoreInst(SplatValue, SplatPtr, /*IsVolatile=*/false, Alignment); S->copyMetadata(II); return S; } } // scatter(vector, splat(ptr), splat(true)) -> store extract(vector, // lastlane), ptr if (ConstMask->isAllOnesValue()) { Align Alignment = cast(II.getArgOperand(2))->getAlignValue(); VectorType *WideLoadTy = cast(II.getArgOperand(1)->getType()); ElementCount VF = WideLoadTy->getElementCount(); Value *RunTimeVF = Builder.CreateElementCount(Builder.getInt32Ty(), VF); Value *LastLane = Builder.CreateSub(RunTimeVF, Builder.getInt32(1)); Value *Extract = Builder.CreateExtractElement(II.getArgOperand(0), LastLane); StoreInst *S = new StoreInst(Extract, SplatPtr, /*IsVolatile=*/false, Alignment); S->copyMetadata(II); return S; } } if (isa(ConstMask->getType())) return nullptr; // Use masked off lanes to simplify operands via SimplifyDemandedVectorElts APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask); APInt PoisonElts(DemandedElts.getBitWidth(), 0); if (Value *V = SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts, PoisonElts)) return replaceOperand(II, 0, V); if (Value *V = SimplifyDemandedVectorElts(II.getOperand(1), DemandedElts, PoisonElts)) return replaceOperand(II, 1, V); return nullptr; } /// This function transforms launder.invariant.group and strip.invariant.group /// like: /// launder(launder(%x)) -> launder(%x) (the result is not the argument) /// launder(strip(%x)) -> launder(%x) /// strip(strip(%x)) -> strip(%x) (the result is not the argument) /// strip(launder(%x)) -> strip(%x) /// This is legal because it preserves the most recent information about /// the presence or absence of invariant.group. static Instruction *simplifyInvariantGroupIntrinsic(IntrinsicInst &II, InstCombinerImpl &IC) { auto *Arg = II.getArgOperand(0); auto *StrippedArg = Arg->stripPointerCasts(); auto *StrippedInvariantGroupsArg = StrippedArg; while (auto *Intr = dyn_cast(StrippedInvariantGroupsArg)) { if (Intr->getIntrinsicID() != Intrinsic::launder_invariant_group && Intr->getIntrinsicID() != Intrinsic::strip_invariant_group) break; StrippedInvariantGroupsArg = Intr->getArgOperand(0)->stripPointerCasts(); } if (StrippedArg == StrippedInvariantGroupsArg) return nullptr; // No launders/strips to remove. Value *Result = nullptr; if (II.getIntrinsicID() == Intrinsic::launder_invariant_group) Result = IC.Builder.CreateLaunderInvariantGroup(StrippedInvariantGroupsArg); else if (II.getIntrinsicID() == Intrinsic::strip_invariant_group) Result = IC.Builder.CreateStripInvariantGroup(StrippedInvariantGroupsArg); else llvm_unreachable( "simplifyInvariantGroupIntrinsic only handles launder and strip"); if (Result->getType()->getPointerAddressSpace() != II.getType()->getPointerAddressSpace()) Result = IC.Builder.CreateAddrSpaceCast(Result, II.getType()); return cast(Result); } static Instruction *foldCttzCtlz(IntrinsicInst &II, InstCombinerImpl &IC) { assert((II.getIntrinsicID() == Intrinsic::cttz || II.getIntrinsicID() == Intrinsic::ctlz) && "Expected cttz or ctlz intrinsic"); bool IsTZ = II.getIntrinsicID() == Intrinsic::cttz; Value *Op0 = II.getArgOperand(0); Value *Op1 = II.getArgOperand(1); Value *X; // ctlz(bitreverse(x)) -> cttz(x) // cttz(bitreverse(x)) -> ctlz(x) if (match(Op0, m_BitReverse(m_Value(X)))) { Intrinsic::ID ID = IsTZ ? Intrinsic::ctlz : Intrinsic::cttz; Function *F = Intrinsic::getDeclaration(II.getModule(), ID, II.getType()); return CallInst::Create(F, {X, II.getArgOperand(1)}); } if (II.getType()->isIntOrIntVectorTy(1)) { // ctlz/cttz i1 Op0 --> not Op0 if (match(Op1, m_Zero())) return BinaryOperator::CreateNot(Op0); // If zero is poison, then the input can be assumed to be "true", so the // instruction simplifies to "false". assert(match(Op1, m_One()) && "Expected ctlz/cttz operand to be 0 or 1"); return IC.replaceInstUsesWith(II, ConstantInt::getNullValue(II.getType())); } // If ctlz/cttz is only used as a shift amount, set is_zero_poison to true. if (II.hasOneUse() && match(Op1, m_Zero()) && match(II.user_back(), m_Shift(m_Value(), m_Specific(&II)))) return IC.replaceOperand(II, 1, IC.Builder.getTrue()); Constant *C; if (IsTZ) { // cttz(-x) -> cttz(x) if (match(Op0, m_Neg(m_Value(X)))) return IC.replaceOperand(II, 0, X); // cttz(-x & x) -> cttz(x) if (match(Op0, m_c_And(m_Neg(m_Value(X)), m_Deferred(X)))) return IC.replaceOperand(II, 0, X); // cttz(sext(x)) -> cttz(zext(x)) if (match(Op0, m_OneUse(m_SExt(m_Value(X))))) { auto *Zext = IC.Builder.CreateZExt(X, II.getType()); auto *CttzZext = IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, Zext, Op1); return IC.replaceInstUsesWith(II, CttzZext); } // Zext doesn't change the number of trailing zeros, so narrow: // cttz(zext(x)) -> zext(cttz(x)) if the 'ZeroIsPoison' parameter is 'true'. if (match(Op0, m_OneUse(m_ZExt(m_Value(X)))) && match(Op1, m_One())) { auto *Cttz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, X, IC.Builder.getTrue()); auto *ZextCttz = IC.Builder.CreateZExt(Cttz, II.getType()); return IC.replaceInstUsesWith(II, ZextCttz); } // cttz(abs(x)) -> cttz(x) // cttz(nabs(x)) -> cttz(x) Value *Y; SelectPatternFlavor SPF = matchSelectPattern(Op0, X, Y).Flavor; if (SPF == SPF_ABS || SPF == SPF_NABS) return IC.replaceOperand(II, 0, X); if (match(Op0, m_Intrinsic(m_Value(X)))) return IC.replaceOperand(II, 0, X); // cttz(shl(%const, %val), 1) --> add(cttz(%const, 1), %val) if (match(Op0, m_Shl(m_ImmConstant(C), m_Value(X))) && match(Op1, m_One())) { Value *ConstCttz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, C, Op1); return BinaryOperator::CreateAdd(ConstCttz, X); } // cttz(lshr exact (%const, %val), 1) --> sub(cttz(%const, 1), %val) if (match(Op0, m_Exact(m_LShr(m_ImmConstant(C), m_Value(X)))) && match(Op1, m_One())) { Value *ConstCttz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, C, Op1); return BinaryOperator::CreateSub(ConstCttz, X); } // cttz(add(lshr(UINT_MAX, %val), 1)) --> sub(width, %val) if (match(Op0, m_Add(m_LShr(m_AllOnes(), m_Value(X)), m_One()))) { Value *Width = ConstantInt::get(II.getType(), II.getType()->getScalarSizeInBits()); return BinaryOperator::CreateSub(Width, X); } } else { // ctlz(lshr(%const, %val), 1) --> add(ctlz(%const, 1), %val) if (match(Op0, m_LShr(m_ImmConstant(C), m_Value(X))) && match(Op1, m_One())) { Value *ConstCtlz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::ctlz, C, Op1); return BinaryOperator::CreateAdd(ConstCtlz, X); } // ctlz(shl nuw (%const, %val), 1) --> sub(ctlz(%const, 1), %val) if (match(Op0, m_NUWShl(m_ImmConstant(C), m_Value(X))) && match(Op1, m_One())) { Value *ConstCtlz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::ctlz, C, Op1); return BinaryOperator::CreateSub(ConstCtlz, X); } } KnownBits Known = IC.computeKnownBits(Op0, 0, &II); // Create a mask for bits above (ctlz) or below (cttz) the first known one. unsigned PossibleZeros = IsTZ ? Known.countMaxTrailingZeros() : Known.countMaxLeadingZeros(); unsigned DefiniteZeros = IsTZ ? Known.countMinTrailingZeros() : Known.countMinLeadingZeros(); // If all bits above (ctlz) or below (cttz) the first known one are known // zero, this value is constant. // FIXME: This should be in InstSimplify because we're replacing an // instruction with a constant. if (PossibleZeros == DefiniteZeros) { auto *C = ConstantInt::get(Op0->getType(), DefiniteZeros); return IC.replaceInstUsesWith(II, C); } // If the input to cttz/ctlz is known to be non-zero, // then change the 'ZeroIsPoison' parameter to 'true' // because we know the zero behavior can't affect the result. if (!Known.One.isZero() || isKnownNonZero(Op0, IC.getSimplifyQuery().getWithInstruction(&II))) { if (!match(II.getArgOperand(1), m_One())) return IC.replaceOperand(II, 1, IC.Builder.getTrue()); } // Add range attribute since known bits can't completely reflect what we know. unsigned BitWidth = Op0->getType()->getScalarSizeInBits(); if (BitWidth != 1 && !II.hasRetAttr(Attribute::Range) && !II.getMetadata(LLVMContext::MD_range)) { ConstantRange Range(APInt(BitWidth, DefiniteZeros), APInt(BitWidth, PossibleZeros + 1)); II.addRangeRetAttr(Range); return &II; } return nullptr; } static Instruction *foldCtpop(IntrinsicInst &II, InstCombinerImpl &IC) { assert(II.getIntrinsicID() == Intrinsic::ctpop && "Expected ctpop intrinsic"); Type *Ty = II.getType(); unsigned BitWidth = Ty->getScalarSizeInBits(); Value *Op0 = II.getArgOperand(0); Value *X, *Y; // ctpop(bitreverse(x)) -> ctpop(x) // ctpop(bswap(x)) -> ctpop(x) if (match(Op0, m_BitReverse(m_Value(X))) || match(Op0, m_BSwap(m_Value(X)))) return IC.replaceOperand(II, 0, X); // ctpop(rot(x)) -> ctpop(x) if ((match(Op0, m_FShl(m_Value(X), m_Value(Y), m_Value())) || match(Op0, m_FShr(m_Value(X), m_Value(Y), m_Value()))) && X == Y) return IC.replaceOperand(II, 0, X); // ctpop(x | -x) -> bitwidth - cttz(x, false) if (Op0->hasOneUse() && match(Op0, m_c_Or(m_Value(X), m_Neg(m_Deferred(X))))) { Function *F = Intrinsic::getDeclaration(II.getModule(), Intrinsic::cttz, Ty); auto *Cttz = IC.Builder.CreateCall(F, {X, IC.Builder.getFalse()}); auto *Bw = ConstantInt::get(Ty, APInt(BitWidth, BitWidth)); return IC.replaceInstUsesWith(II, IC.Builder.CreateSub(Bw, Cttz)); } // ctpop(~x & (x - 1)) -> cttz(x, false) if (match(Op0, m_c_And(m_Not(m_Value(X)), m_Add(m_Deferred(X), m_AllOnes())))) { Function *F = Intrinsic::getDeclaration(II.getModule(), Intrinsic::cttz, Ty); return CallInst::Create(F, {X, IC.Builder.getFalse()}); } // Zext doesn't change the number of set bits, so narrow: // ctpop (zext X) --> zext (ctpop X) if (match(Op0, m_OneUse(m_ZExt(m_Value(X))))) { Value *NarrowPop = IC.Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, X); return CastInst::Create(Instruction::ZExt, NarrowPop, Ty); } KnownBits Known(BitWidth); IC.computeKnownBits(Op0, Known, 0, &II); // If all bits are zero except for exactly one fixed bit, then the result // must be 0 or 1, and we can get that answer by shifting to LSB: // ctpop (X & 32) --> (X & 32) >> 5 // TODO: Investigate removing this as its likely unnecessary given the below // `isKnownToBeAPowerOfTwo` check. if ((~Known.Zero).isPowerOf2()) return BinaryOperator::CreateLShr( Op0, ConstantInt::get(Ty, (~Known.Zero).exactLogBase2())); // More generally we can also handle non-constant power of 2 patterns such as // shl/shr(Pow2, X), (X & -X), etc... by transforming: // ctpop(Pow2OrZero) --> icmp ne X, 0 if (IC.isKnownToBeAPowerOfTwo(Op0, /* OrZero */ true)) return CastInst::Create(Instruction::ZExt, IC.Builder.CreateICmp(ICmpInst::ICMP_NE, Op0, Constant::getNullValue(Ty)), Ty); // Add range attribute since known bits can't completely reflect what we know. if (BitWidth != 1 && !II.hasRetAttr(Attribute::Range) && !II.getMetadata(LLVMContext::MD_range)) { ConstantRange Range(APInt(BitWidth, Known.countMinPopulation()), APInt(BitWidth, Known.countMaxPopulation() + 1)); II.addRangeRetAttr(Range); return &II; } return nullptr; } /// Convert a table lookup to shufflevector if the mask is constant. /// This could benefit tbl1 if the mask is { 7,6,5,4,3,2,1,0 }, in /// which case we could lower the shufflevector with rev64 instructions /// as it's actually a byte reverse. static Value *simplifyNeonTbl1(const IntrinsicInst &II, InstCombiner::BuilderTy &Builder) { // Bail out if the mask is not a constant. auto *C = dyn_cast(II.getArgOperand(1)); if (!C) return nullptr; auto *VecTy = cast(II.getType()); unsigned NumElts = VecTy->getNumElements(); // Only perform this transformation for <8 x i8> vector types. if (!VecTy->getElementType()->isIntegerTy(8) || NumElts != 8) return nullptr; int Indexes[8]; for (unsigned I = 0; I < NumElts; ++I) { Constant *COp = C->getAggregateElement(I); if (!COp || !isa(COp)) return nullptr; Indexes[I] = cast(COp)->getLimitedValue(); // Make sure the mask indices are in range. if ((unsigned)Indexes[I] >= NumElts) return nullptr; } auto *V1 = II.getArgOperand(0); auto *V2 = Constant::getNullValue(V1->getType()); return Builder.CreateShuffleVector(V1, V2, ArrayRef(Indexes)); } // Returns true iff the 2 intrinsics have the same operands, limiting the // comparison to the first NumOperands. static bool haveSameOperands(const IntrinsicInst &I, const IntrinsicInst &E, unsigned NumOperands) { assert(I.arg_size() >= NumOperands && "Not enough operands"); assert(E.arg_size() >= NumOperands && "Not enough operands"); for (unsigned i = 0; i < NumOperands; i++) if (I.getArgOperand(i) != E.getArgOperand(i)) return false; return true; } // Remove trivially empty start/end intrinsic ranges, i.e. a start // immediately followed by an end (ignoring debuginfo or other // start/end intrinsics in between). As this handles only the most trivial // cases, tracking the nesting level is not needed: // // call @llvm.foo.start(i1 0) // call @llvm.foo.start(i1 0) ; This one won't be skipped: it will be removed // call @llvm.foo.end(i1 0) // call @llvm.foo.end(i1 0) ; &I static bool removeTriviallyEmptyRange(IntrinsicInst &EndI, InstCombinerImpl &IC, std::function IsStart) { // We start from the end intrinsic and scan backwards, so that InstCombine // has already processed (and potentially removed) all the instructions // before the end intrinsic. BasicBlock::reverse_iterator BI(EndI), BE(EndI.getParent()->rend()); for (; BI != BE; ++BI) { if (auto *I = dyn_cast(&*BI)) { if (I->isDebugOrPseudoInst() || I->getIntrinsicID() == EndI.getIntrinsicID()) continue; if (IsStart(*I)) { if (haveSameOperands(EndI, *I, EndI.arg_size())) { IC.eraseInstFromFunction(*I); IC.eraseInstFromFunction(EndI); return true; } // Skip start intrinsics that don't pair with this end intrinsic. continue; } } break; } return false; } Instruction *InstCombinerImpl::visitVAEndInst(VAEndInst &I) { removeTriviallyEmptyRange(I, *this, [](const IntrinsicInst &I) { return I.getIntrinsicID() == Intrinsic::vastart || I.getIntrinsicID() == Intrinsic::vacopy; }); return nullptr; } static CallInst *canonicalizeConstantArg0ToArg1(CallInst &Call) { assert(Call.arg_size() > 1 && "Need at least 2 args to swap"); Value *Arg0 = Call.getArgOperand(0), *Arg1 = Call.getArgOperand(1); if (isa(Arg0) && !isa(Arg1)) { Call.setArgOperand(0, Arg1); Call.setArgOperand(1, Arg0); return &Call; } return nullptr; } /// Creates a result tuple for an overflow intrinsic \p II with a given /// \p Result and a constant \p Overflow value. static Instruction *createOverflowTuple(IntrinsicInst *II, Value *Result, Constant *Overflow) { Constant *V[] = {PoisonValue::get(Result->getType()), Overflow}; StructType *ST = cast(II->getType()); Constant *Struct = ConstantStruct::get(ST, V); return InsertValueInst::Create(Struct, Result, 0); } Instruction * InstCombinerImpl::foldIntrinsicWithOverflowCommon(IntrinsicInst *II) { WithOverflowInst *WO = cast(II); Value *OperationResult = nullptr; Constant *OverflowResult = nullptr; if (OptimizeOverflowCheck(WO->getBinaryOp(), WO->isSigned(), WO->getLHS(), WO->getRHS(), *WO, OperationResult, OverflowResult)) return createOverflowTuple(WO, OperationResult, OverflowResult); return nullptr; } static bool inputDenormalIsIEEE(const Function &F, const Type *Ty) { Ty = Ty->getScalarType(); return F.getDenormalMode(Ty->getFltSemantics()).Input == DenormalMode::IEEE; } static bool inputDenormalIsDAZ(const Function &F, const Type *Ty) { Ty = Ty->getScalarType(); return F.getDenormalMode(Ty->getFltSemantics()).inputsAreZero(); } /// \returns the compare predicate type if the test performed by /// llvm.is.fpclass(x, \p Mask) is equivalent to fcmp o__ x, 0.0 with the /// floating-point environment assumed for \p F for type \p Ty static FCmpInst::Predicate fpclassTestIsFCmp0(FPClassTest Mask, const Function &F, Type *Ty) { switch (static_cast(Mask)) { case fcZero: if (inputDenormalIsIEEE(F, Ty)) return FCmpInst::FCMP_OEQ; break; case fcZero | fcSubnormal: if (inputDenormalIsDAZ(F, Ty)) return FCmpInst::FCMP_OEQ; break; case fcPositive | fcNegZero: if (inputDenormalIsIEEE(F, Ty)) return FCmpInst::FCMP_OGE; break; case fcPositive | fcNegZero | fcNegSubnormal: if (inputDenormalIsDAZ(F, Ty)) return FCmpInst::FCMP_OGE; break; case fcPosSubnormal | fcPosNormal | fcPosInf: if (inputDenormalIsIEEE(F, Ty)) return FCmpInst::FCMP_OGT; break; case fcNegative | fcPosZero: if (inputDenormalIsIEEE(F, Ty)) return FCmpInst::FCMP_OLE; break; case fcNegative | fcPosZero | fcPosSubnormal: if (inputDenormalIsDAZ(F, Ty)) return FCmpInst::FCMP_OLE; break; case fcNegSubnormal | fcNegNormal | fcNegInf: if (inputDenormalIsIEEE(F, Ty)) return FCmpInst::FCMP_OLT; break; case fcPosNormal | fcPosInf: if (inputDenormalIsDAZ(F, Ty)) return FCmpInst::FCMP_OGT; break; case fcNegNormal | fcNegInf: if (inputDenormalIsDAZ(F, Ty)) return FCmpInst::FCMP_OLT; break; case ~fcZero & ~fcNan: if (inputDenormalIsIEEE(F, Ty)) return FCmpInst::FCMP_ONE; break; case ~(fcZero | fcSubnormal) & ~fcNan: if (inputDenormalIsDAZ(F, Ty)) return FCmpInst::FCMP_ONE; break; default: break; } return FCmpInst::BAD_FCMP_PREDICATE; } Instruction *InstCombinerImpl::foldIntrinsicIsFPClass(IntrinsicInst &II) { Value *Src0 = II.getArgOperand(0); Value *Src1 = II.getArgOperand(1); const ConstantInt *CMask = cast(Src1); FPClassTest Mask = static_cast(CMask->getZExtValue()); const bool IsUnordered = (Mask & fcNan) == fcNan; const bool IsOrdered = (Mask & fcNan) == fcNone; const FPClassTest OrderedMask = Mask & ~fcNan; const FPClassTest OrderedInvertedMask = ~OrderedMask & ~fcNan; const bool IsStrict = II.getFunction()->getAttributes().hasFnAttr(Attribute::StrictFP); Value *FNegSrc; if (match(Src0, m_FNeg(m_Value(FNegSrc)))) { // is.fpclass (fneg x), mask -> is.fpclass x, (fneg mask) II.setArgOperand(1, ConstantInt::get(Src1->getType(), fneg(Mask))); return replaceOperand(II, 0, FNegSrc); } Value *FAbsSrc; if (match(Src0, m_FAbs(m_Value(FAbsSrc)))) { II.setArgOperand(1, ConstantInt::get(Src1->getType(), inverse_fabs(Mask))); return replaceOperand(II, 0, FAbsSrc); } if ((OrderedMask == fcInf || OrderedInvertedMask == fcInf) && (IsOrdered || IsUnordered) && !IsStrict) { // is.fpclass(x, fcInf) -> fcmp oeq fabs(x), +inf // is.fpclass(x, ~fcInf) -> fcmp one fabs(x), +inf // is.fpclass(x, fcInf|fcNan) -> fcmp ueq fabs(x), +inf // is.fpclass(x, ~(fcInf|fcNan)) -> fcmp une fabs(x), +inf Constant *Inf = ConstantFP::getInfinity(Src0->getType()); FCmpInst::Predicate Pred = IsUnordered ? FCmpInst::FCMP_UEQ : FCmpInst::FCMP_OEQ; if (OrderedInvertedMask == fcInf) Pred = IsUnordered ? FCmpInst::FCMP_UNE : FCmpInst::FCMP_ONE; Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Src0); Value *CmpInf = Builder.CreateFCmp(Pred, Fabs, Inf); CmpInf->takeName(&II); return replaceInstUsesWith(II, CmpInf); } if ((OrderedMask == fcPosInf || OrderedMask == fcNegInf) && (IsOrdered || IsUnordered) && !IsStrict) { // is.fpclass(x, fcPosInf) -> fcmp oeq x, +inf // is.fpclass(x, fcNegInf) -> fcmp oeq x, -inf // is.fpclass(x, fcPosInf|fcNan) -> fcmp ueq x, +inf // is.fpclass(x, fcNegInf|fcNan) -> fcmp ueq x, -inf Constant *Inf = ConstantFP::getInfinity(Src0->getType(), OrderedMask == fcNegInf); Value *EqInf = IsUnordered ? Builder.CreateFCmpUEQ(Src0, Inf) : Builder.CreateFCmpOEQ(Src0, Inf); EqInf->takeName(&II); return replaceInstUsesWith(II, EqInf); } if ((OrderedInvertedMask == fcPosInf || OrderedInvertedMask == fcNegInf) && (IsOrdered || IsUnordered) && !IsStrict) { // is.fpclass(x, ~fcPosInf) -> fcmp one x, +inf // is.fpclass(x, ~fcNegInf) -> fcmp one x, -inf // is.fpclass(x, ~fcPosInf|fcNan) -> fcmp une x, +inf // is.fpclass(x, ~fcNegInf|fcNan) -> fcmp une x, -inf Constant *Inf = ConstantFP::getInfinity(Src0->getType(), OrderedInvertedMask == fcNegInf); Value *NeInf = IsUnordered ? Builder.CreateFCmpUNE(Src0, Inf) : Builder.CreateFCmpONE(Src0, Inf); NeInf->takeName(&II); return replaceInstUsesWith(II, NeInf); } if (Mask == fcNan && !IsStrict) { // Equivalent of isnan. Replace with standard fcmp if we don't care about FP // exceptions. Value *IsNan = Builder.CreateFCmpUNO(Src0, ConstantFP::getZero(Src0->getType())); IsNan->takeName(&II); return replaceInstUsesWith(II, IsNan); } if (Mask == (~fcNan & fcAllFlags) && !IsStrict) { // Equivalent of !isnan. Replace with standard fcmp. Value *FCmp = Builder.CreateFCmpORD(Src0, ConstantFP::getZero(Src0->getType())); FCmp->takeName(&II); return replaceInstUsesWith(II, FCmp); } FCmpInst::Predicate PredType = FCmpInst::BAD_FCMP_PREDICATE; // Try to replace with an fcmp with 0 // // is.fpclass(x, fcZero) -> fcmp oeq x, 0.0 // is.fpclass(x, fcZero | fcNan) -> fcmp ueq x, 0.0 // is.fpclass(x, ~fcZero & ~fcNan) -> fcmp one x, 0.0 // is.fpclass(x, ~fcZero) -> fcmp une x, 0.0 // // is.fpclass(x, fcPosSubnormal | fcPosNormal | fcPosInf) -> fcmp ogt x, 0.0 // is.fpclass(x, fcPositive | fcNegZero) -> fcmp oge x, 0.0 // // is.fpclass(x, fcNegSubnormal | fcNegNormal | fcNegInf) -> fcmp olt x, 0.0 // is.fpclass(x, fcNegative | fcPosZero) -> fcmp ole x, 0.0 // if (!IsStrict && (IsOrdered || IsUnordered) && (PredType = fpclassTestIsFCmp0(OrderedMask, *II.getFunction(), Src0->getType())) != FCmpInst::BAD_FCMP_PREDICATE) { Constant *Zero = ConstantFP::getZero(Src0->getType()); // Equivalent of == 0. Value *FCmp = Builder.CreateFCmp( IsUnordered ? FCmpInst::getUnorderedPredicate(PredType) : PredType, Src0, Zero); FCmp->takeName(&II); return replaceInstUsesWith(II, FCmp); } KnownFPClass Known = computeKnownFPClass(Src0, Mask, &II); // Clear test bits we know must be false from the source value. // fp_class (nnan x), qnan|snan|other -> fp_class (nnan x), other // fp_class (ninf x), ninf|pinf|other -> fp_class (ninf x), other if ((Mask & Known.KnownFPClasses) != Mask) { II.setArgOperand( 1, ConstantInt::get(Src1->getType(), Mask & Known.KnownFPClasses)); return &II; } // If none of the tests which can return false are possible, fold to true. // fp_class (nnan x), ~(qnan|snan) -> true // fp_class (ninf x), ~(ninf|pinf) -> true if (Mask == Known.KnownFPClasses) return replaceInstUsesWith(II, ConstantInt::get(II.getType(), true)); return nullptr; } static std::optional getKnownSign(Value *Op, const SimplifyQuery &SQ) { KnownBits Known = computeKnownBits(Op, /*Depth=*/0, SQ); if (Known.isNonNegative()) return false; if (Known.isNegative()) return true; Value *X, *Y; if (match(Op, m_NSWSub(m_Value(X), m_Value(Y)))) return isImpliedByDomCondition(ICmpInst::ICMP_SLT, X, Y, SQ.CxtI, SQ.DL); return std::nullopt; } static std::optional getKnownSignOrZero(Value *Op, const SimplifyQuery &SQ) { if (std::optional Sign = getKnownSign(Op, SQ)) return Sign; Value *X, *Y; if (match(Op, m_NSWSub(m_Value(X), m_Value(Y)))) return isImpliedByDomCondition(ICmpInst::ICMP_SLE, X, Y, SQ.CxtI, SQ.DL); return std::nullopt; } /// Return true if two values \p Op0 and \p Op1 are known to have the same sign. static bool signBitMustBeTheSame(Value *Op0, Value *Op1, const SimplifyQuery &SQ) { std::optional Known1 = getKnownSign(Op1, SQ); if (!Known1) return false; std::optional Known0 = getKnownSign(Op0, SQ); if (!Known0) return false; return *Known0 == *Known1; } /// Try to canonicalize min/max(X + C0, C1) as min/max(X, C1 - C0) + C0. This /// can trigger other combines. static Instruction *moveAddAfterMinMax(IntrinsicInst *II, InstCombiner::BuilderTy &Builder) { Intrinsic::ID MinMaxID = II->getIntrinsicID(); assert((MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin || MinMaxID == Intrinsic::umax || MinMaxID == Intrinsic::umin) && "Expected a min or max intrinsic"); // TODO: Match vectors with undef elements, but undef may not propagate. Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1); Value *X; const APInt *C0, *C1; if (!match(Op0, m_OneUse(m_Add(m_Value(X), m_APInt(C0)))) || !match(Op1, m_APInt(C1))) return nullptr; // Check for necessary no-wrap and overflow constraints. bool IsSigned = MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin; auto *Add = cast(Op0); if ((IsSigned && !Add->hasNoSignedWrap()) || (!IsSigned && !Add->hasNoUnsignedWrap())) return nullptr; // If the constant difference overflows, then instsimplify should reduce the // min/max to the add or C1. bool Overflow; APInt CDiff = IsSigned ? C1->ssub_ov(*C0, Overflow) : C1->usub_ov(*C0, Overflow); assert(!Overflow && "Expected simplify of min/max"); // min/max (add X, C0), C1 --> add (min/max X, C1 - C0), C0 // Note: the "mismatched" no-overflow setting does not propagate. Constant *NewMinMaxC = ConstantInt::get(II->getType(), CDiff); Value *NewMinMax = Builder.CreateBinaryIntrinsic(MinMaxID, X, NewMinMaxC); return IsSigned ? BinaryOperator::CreateNSWAdd(NewMinMax, Add->getOperand(1)) : BinaryOperator::CreateNUWAdd(NewMinMax, Add->getOperand(1)); } /// Match a sadd_sat or ssub_sat which is using min/max to clamp the value. Instruction *InstCombinerImpl::matchSAddSubSat(IntrinsicInst &MinMax1) { Type *Ty = MinMax1.getType(); // We are looking for a tree of: // max(INT_MIN, min(INT_MAX, add(sext(A), sext(B)))) // Where the min and max could be reversed Instruction *MinMax2; BinaryOperator *AddSub; const APInt *MinValue, *MaxValue; if (match(&MinMax1, m_SMin(m_Instruction(MinMax2), m_APInt(MaxValue)))) { if (!match(MinMax2, m_SMax(m_BinOp(AddSub), m_APInt(MinValue)))) return nullptr; } else if (match(&MinMax1, m_SMax(m_Instruction(MinMax2), m_APInt(MinValue)))) { if (!match(MinMax2, m_SMin(m_BinOp(AddSub), m_APInt(MaxValue)))) return nullptr; } else return nullptr; // Check that the constants clamp a saturate, and that the new type would be // sensible to convert to. if (!(*MaxValue + 1).isPowerOf2() || -*MinValue != *MaxValue + 1) return nullptr; // In what bitwidth can this be treated as saturating arithmetics? unsigned NewBitWidth = (*MaxValue + 1).logBase2() + 1; // FIXME: This isn't quite right for vectors, but using the scalar type is a // good first approximation for what should be done there. if (!shouldChangeType(Ty->getScalarType()->getIntegerBitWidth(), NewBitWidth)) return nullptr; // Also make sure that the inner min/max and the add/sub have one use. if (!MinMax2->hasOneUse() || !AddSub->hasOneUse()) return nullptr; // Create the new type (which can be a vector type) Type *NewTy = Ty->getWithNewBitWidth(NewBitWidth); Intrinsic::ID IntrinsicID; if (AddSub->getOpcode() == Instruction::Add) IntrinsicID = Intrinsic::sadd_sat; else if (AddSub->getOpcode() == Instruction::Sub) IntrinsicID = Intrinsic::ssub_sat; else return nullptr; // The two operands of the add/sub must be nsw-truncatable to the NewTy. This // is usually achieved via a sext from a smaller type. if (ComputeMaxSignificantBits(AddSub->getOperand(0), 0, AddSub) > NewBitWidth || ComputeMaxSignificantBits(AddSub->getOperand(1), 0, AddSub) > NewBitWidth) return nullptr; // Finally create and return the sat intrinsic, truncated to the new type Function *F = Intrinsic::getDeclaration(MinMax1.getModule(), IntrinsicID, NewTy); Value *AT = Builder.CreateTrunc(AddSub->getOperand(0), NewTy); Value *BT = Builder.CreateTrunc(AddSub->getOperand(1), NewTy); Value *Sat = Builder.CreateCall(F, {AT, BT}); return CastInst::Create(Instruction::SExt, Sat, Ty); } /// If we have a clamp pattern like max (min X, 42), 41 -- where the output /// can only be one of two possible constant values -- turn that into a select /// of constants. static Instruction *foldClampRangeOfTwo(IntrinsicInst *II, InstCombiner::BuilderTy &Builder) { Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); Value *X; const APInt *C0, *C1; if (!match(I1, m_APInt(C1)) || !I0->hasOneUse()) return nullptr; CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE; switch (II->getIntrinsicID()) { case Intrinsic::smax: if (match(I0, m_SMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1) Pred = ICmpInst::ICMP_SGT; break; case Intrinsic::smin: if (match(I0, m_SMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1) Pred = ICmpInst::ICMP_SLT; break; case Intrinsic::umax: if (match(I0, m_UMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1) Pred = ICmpInst::ICMP_UGT; break; case Intrinsic::umin: if (match(I0, m_UMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1) Pred = ICmpInst::ICMP_ULT; break; default: llvm_unreachable("Expected min/max intrinsic"); } if (Pred == CmpInst::BAD_ICMP_PREDICATE) return nullptr; // max (min X, 42), 41 --> X > 41 ? 42 : 41 // min (max X, 42), 43 --> X < 43 ? 42 : 43 Value *Cmp = Builder.CreateICmp(Pred, X, I1); return SelectInst::Create(Cmp, ConstantInt::get(II->getType(), *C0), I1); } /// If this min/max has a constant operand and an operand that is a matching /// min/max with a constant operand, constant-fold the 2 constant operands. static Value *reassociateMinMaxWithConstants(IntrinsicInst *II, IRBuilderBase &Builder, const SimplifyQuery &SQ) { Intrinsic::ID MinMaxID = II->getIntrinsicID(); auto *LHS = dyn_cast(II->getArgOperand(0)); if (!LHS) return nullptr; Constant *C0, *C1; if (!match(LHS->getArgOperand(1), m_ImmConstant(C0)) || !match(II->getArgOperand(1), m_ImmConstant(C1))) return nullptr; // max (max X, C0), C1 --> max X, (max C0, C1) // min (min X, C0), C1 --> min X, (min C0, C1) // umax (smax X, nneg C0), nneg C1 --> smax X, (umax C0, C1) // smin (umin X, nneg C0), nneg C1 --> umin X, (smin C0, C1) Intrinsic::ID InnerMinMaxID = LHS->getIntrinsicID(); if (InnerMinMaxID != MinMaxID && !(((MinMaxID == Intrinsic::umax && InnerMinMaxID == Intrinsic::smax) || (MinMaxID == Intrinsic::smin && InnerMinMaxID == Intrinsic::umin)) && isKnownNonNegative(C0, SQ) && isKnownNonNegative(C1, SQ))) return nullptr; ICmpInst::Predicate Pred = MinMaxIntrinsic::getPredicate(MinMaxID); Value *CondC = Builder.CreateICmp(Pred, C0, C1); Value *NewC = Builder.CreateSelect(CondC, C0, C1); return Builder.CreateIntrinsic(InnerMinMaxID, II->getType(), {LHS->getArgOperand(0), NewC}); } /// If this min/max has a matching min/max operand with a constant, try to push /// the constant operand into this instruction. This can enable more folds. static Instruction * reassociateMinMaxWithConstantInOperand(IntrinsicInst *II, InstCombiner::BuilderTy &Builder) { // Match and capture a min/max operand candidate. Value *X, *Y; Constant *C; Instruction *Inner; if (!match(II, m_c_MaxOrMin(m_OneUse(m_CombineAnd( m_Instruction(Inner), m_MaxOrMin(m_Value(X), m_ImmConstant(C)))), m_Value(Y)))) return nullptr; // The inner op must match. Check for constants to avoid infinite loops. Intrinsic::ID MinMaxID = II->getIntrinsicID(); auto *InnerMM = dyn_cast(Inner); if (!InnerMM || InnerMM->getIntrinsicID() != MinMaxID || match(X, m_ImmConstant()) || match(Y, m_ImmConstant())) return nullptr; // max (max X, C), Y --> max (max X, Y), C Function *MinMax = Intrinsic::getDeclaration(II->getModule(), MinMaxID, II->getType()); Value *NewInner = Builder.CreateBinaryIntrinsic(MinMaxID, X, Y); NewInner->takeName(Inner); return CallInst::Create(MinMax, {NewInner, C}); } /// Reduce a sequence of min/max intrinsics with a common operand. static Instruction *factorizeMinMaxTree(IntrinsicInst *II) { // Match 3 of the same min/max ops. Example: umin(umin(), umin()). auto *LHS = dyn_cast(II->getArgOperand(0)); auto *RHS = dyn_cast(II->getArgOperand(1)); Intrinsic::ID MinMaxID = II->getIntrinsicID(); if (!LHS || !RHS || LHS->getIntrinsicID() != MinMaxID || RHS->getIntrinsicID() != MinMaxID || (!LHS->hasOneUse() && !RHS->hasOneUse())) return nullptr; Value *A = LHS->getArgOperand(0); Value *B = LHS->getArgOperand(1); Value *C = RHS->getArgOperand(0); Value *D = RHS->getArgOperand(1); // Look for a common operand. Value *MinMaxOp = nullptr; Value *ThirdOp = nullptr; if (LHS->hasOneUse()) { // If the LHS is only used in this chain and the RHS is used outside of it, // reuse the RHS min/max because that will eliminate the LHS. if (D == A || C == A) { // min(min(a, b), min(c, a)) --> min(min(c, a), b) // min(min(a, b), min(a, d)) --> min(min(a, d), b) MinMaxOp = RHS; ThirdOp = B; } else if (D == B || C == B) { // min(min(a, b), min(c, b)) --> min(min(c, b), a) // min(min(a, b), min(b, d)) --> min(min(b, d), a) MinMaxOp = RHS; ThirdOp = A; } } else { assert(RHS->hasOneUse() && "Expected one-use operand"); // Reuse the LHS. This will eliminate the RHS. if (D == A || D == B) { // min(min(a, b), min(c, a)) --> min(min(a, b), c) // min(min(a, b), min(c, b)) --> min(min(a, b), c) MinMaxOp = LHS; ThirdOp = C; } else if (C == A || C == B) { // min(min(a, b), min(b, d)) --> min(min(a, b), d) // min(min(a, b), min(c, b)) --> min(min(a, b), d) MinMaxOp = LHS; ThirdOp = D; } } if (!MinMaxOp || !ThirdOp) return nullptr; Module *Mod = II->getModule(); Function *MinMax = Intrinsic::getDeclaration(Mod, MinMaxID, II->getType()); return CallInst::Create(MinMax, { MinMaxOp, ThirdOp }); } /// If all arguments of the intrinsic are unary shuffles with the same mask, /// try to shuffle after the intrinsic. static Instruction * foldShuffledIntrinsicOperands(IntrinsicInst *II, InstCombiner::BuilderTy &Builder) { // TODO: This should be extended to handle other intrinsics like fshl, ctpop, // etc. Use llvm::isTriviallyVectorizable() and related to determine // which intrinsics are safe to shuffle? switch (II->getIntrinsicID()) { case Intrinsic::smax: case Intrinsic::smin: case Intrinsic::umax: case Intrinsic::umin: case Intrinsic::fma: case Intrinsic::fshl: case Intrinsic::fshr: break; default: return nullptr; } Value *X; ArrayRef Mask; if (!match(II->getArgOperand(0), m_Shuffle(m_Value(X), m_Undef(), m_Mask(Mask)))) return nullptr; // At least 1 operand must have 1 use because we are creating 2 instructions. if (none_of(II->args(), [](Value *V) { return V->hasOneUse(); })) return nullptr; // See if all arguments are shuffled with the same mask. SmallVector NewArgs(II->arg_size()); NewArgs[0] = X; Type *SrcTy = X->getType(); for (unsigned i = 1, e = II->arg_size(); i != e; ++i) { if (!match(II->getArgOperand(i), m_Shuffle(m_Value(X), m_Undef(), m_SpecificMask(Mask))) || X->getType() != SrcTy) return nullptr; NewArgs[i] = X; } // intrinsic (shuf X, M), (shuf Y, M), ... --> shuf (intrinsic X, Y, ...), M Instruction *FPI = isa(II) ? II : nullptr; Value *NewIntrinsic = Builder.CreateIntrinsic(II->getIntrinsicID(), SrcTy, NewArgs, FPI); return new ShuffleVectorInst(NewIntrinsic, Mask); } /// Fold the following cases and accepts bswap and bitreverse intrinsics: /// bswap(logic_op(bswap(x), y)) --> logic_op(x, bswap(y)) /// bswap(logic_op(bswap(x), bswap(y))) --> logic_op(x, y) (ignores multiuse) template static Instruction *foldBitOrderCrossLogicOp(Value *V, InstCombiner::BuilderTy &Builder) { static_assert(IntrID == Intrinsic::bswap || IntrID == Intrinsic::bitreverse, "This helper only supports BSWAP and BITREVERSE intrinsics"); Value *X, *Y; // Find bitwise logic op. Check that it is a BinaryOperator explicitly so we // don't match ConstantExpr that aren't meaningful for this transform. if (match(V, m_OneUse(m_BitwiseLogic(m_Value(X), m_Value(Y)))) && isa(V)) { Value *OldReorderX, *OldReorderY; BinaryOperator::BinaryOps Op = cast(V)->getOpcode(); // If both X and Y are bswap/bitreverse, the transform reduces the number // of instructions even if there's multiuse. // If only one operand is bswap/bitreverse, we need to ensure the operand // have only one use. if (match(X, m_Intrinsic(m_Value(OldReorderX))) && match(Y, m_Intrinsic(m_Value(OldReorderY)))) { return BinaryOperator::Create(Op, OldReorderX, OldReorderY); } if (match(X, m_OneUse(m_Intrinsic(m_Value(OldReorderX))))) { Value *NewReorder = Builder.CreateUnaryIntrinsic(IntrID, Y); return BinaryOperator::Create(Op, OldReorderX, NewReorder); } if (match(Y, m_OneUse(m_Intrinsic(m_Value(OldReorderY))))) { Value *NewReorder = Builder.CreateUnaryIntrinsic(IntrID, X); return BinaryOperator::Create(Op, NewReorder, OldReorderY); } } return nullptr; } static Value *simplifyReductionOperand(Value *Arg, bool CanReorderLanes) { if (!CanReorderLanes) return nullptr; Value *V; if (match(Arg, m_VecReverse(m_Value(V)))) return V; ArrayRef Mask; if (!isa(Arg->getType()) || !match(Arg, m_Shuffle(m_Value(V), m_Undef(), m_Mask(Mask))) || !cast(Arg)->isSingleSource()) return nullptr; int Sz = Mask.size(); SmallBitVector UsedIndices(Sz); for (int Idx : Mask) { if (Idx == PoisonMaskElem || UsedIndices.test(Idx)) return nullptr; UsedIndices.set(Idx); } // Can remove shuffle iff just shuffled elements, no repeats, undefs, or // other changes. return UsedIndices.all() ? V : nullptr; } /// Fold an unsigned minimum of trailing or leading zero bits counts: /// umin(cttz(CtOp, ZeroUndef), ConstOp) --> cttz(CtOp | (1 << ConstOp)) /// umin(ctlz(CtOp, ZeroUndef), ConstOp) --> ctlz(CtOp | (SignedMin /// >> ConstOp)) template static Value * foldMinimumOverTrailingOrLeadingZeroCount(Value *I0, Value *I1, const DataLayout &DL, InstCombiner::BuilderTy &Builder) { static_assert(IntrID == Intrinsic::cttz || IntrID == Intrinsic::ctlz, "This helper only supports cttz and ctlz intrinsics"); Value *CtOp; Value *ZeroUndef; if (!match(I0, m_OneUse(m_Intrinsic(m_Value(CtOp), m_Value(ZeroUndef))))) return nullptr; unsigned BitWidth = I1->getType()->getScalarSizeInBits(); auto LessBitWidth = [BitWidth](auto &C) { return C.ult(BitWidth); }; if (!match(I1, m_CheckedInt(LessBitWidth))) // We have a constant >= BitWidth (which can be handled by CVP) // or a non-splat vector with elements < and >= BitWidth return nullptr; Type *Ty = I1->getType(); Constant *NewConst = ConstantFoldBinaryOpOperands( IntrID == Intrinsic::cttz ? Instruction::Shl : Instruction::LShr, IntrID == Intrinsic::cttz ? ConstantInt::get(Ty, 1) : ConstantInt::get(Ty, APInt::getSignedMinValue(BitWidth)), cast(I1), DL); return Builder.CreateBinaryIntrinsic( IntrID, Builder.CreateOr(CtOp, NewConst), ConstantInt::getTrue(ZeroUndef->getType())); } /// CallInst simplification. This mostly only handles folding of intrinsic /// instructions. For normal calls, it allows visitCallBase to do the heavy /// lifting. Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) { // Don't try to simplify calls without uses. It will not do anything useful, // but will result in the following folds being skipped. if (!CI.use_empty()) { SmallVector Args; Args.reserve(CI.arg_size()); for (Value *Op : CI.args()) Args.push_back(Op); if (Value *V = simplifyCall(&CI, CI.getCalledOperand(), Args, SQ.getWithInstruction(&CI))) return replaceInstUsesWith(CI, V); } if (Value *FreedOp = getFreedOperand(&CI, &TLI)) return visitFree(CI, FreedOp); // If the caller function (i.e. us, the function that contains this CallInst) // is nounwind, mark the call as nounwind, even if the callee isn't. if (CI.getFunction()->doesNotThrow() && !CI.doesNotThrow()) { CI.setDoesNotThrow(); return &CI; } IntrinsicInst *II = dyn_cast(&CI); if (!II) return visitCallBase(CI); // For atomic unordered mem intrinsics if len is not a positive or // not a multiple of element size then behavior is undefined. if (auto *AMI = dyn_cast(II)) if (ConstantInt *NumBytes = dyn_cast(AMI->getLength())) if (NumBytes->isNegative() || (NumBytes->getZExtValue() % AMI->getElementSizeInBytes() != 0)) { CreateNonTerminatorUnreachable(AMI); assert(AMI->getType()->isVoidTy() && "non void atomic unordered mem intrinsic"); return eraseInstFromFunction(*AMI); } // Intrinsics cannot occur in an invoke or a callbr, so handle them here // instead of in visitCallBase. if (auto *MI = dyn_cast(II)) { bool Changed = false; // memmove/cpy/set of zero bytes is a noop. if (Constant *NumBytes = dyn_cast(MI->getLength())) { if (NumBytes->isNullValue()) return eraseInstFromFunction(CI); } // No other transformations apply to volatile transfers. if (auto *M = dyn_cast(MI)) if (M->isVolatile()) return nullptr; // If we have a memmove and the source operation is a constant global, // then the source and dest pointers can't alias, so we can change this // into a call to memcpy. if (auto *MMI = dyn_cast(MI)) { if (GlobalVariable *GVSrc = dyn_cast(MMI->getSource())) if (GVSrc->isConstant()) { Module *M = CI.getModule(); Intrinsic::ID MemCpyID = isa(MMI) ? Intrinsic::memcpy_element_unordered_atomic : Intrinsic::memcpy; Type *Tys[3] = { CI.getArgOperand(0)->getType(), CI.getArgOperand(1)->getType(), CI.getArgOperand(2)->getType() }; CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys)); Changed = true; } } if (AnyMemTransferInst *MTI = dyn_cast(MI)) { // memmove(x,x,size) -> noop. if (MTI->getSource() == MTI->getDest()) return eraseInstFromFunction(CI); } // If we can determine a pointer alignment that is bigger than currently // set, update the alignment. if (auto *MTI = dyn_cast(MI)) { if (Instruction *I = SimplifyAnyMemTransfer(MTI)) return I; } else if (auto *MSI = dyn_cast(MI)) { if (Instruction *I = SimplifyAnyMemSet(MSI)) return I; } if (Changed) return II; } // For fixed width vector result intrinsics, use the generic demanded vector // support. if (auto *IIFVTy = dyn_cast(II->getType())) { auto VWidth = IIFVTy->getNumElements(); APInt PoisonElts(VWidth, 0); APInt AllOnesEltMask(APInt::getAllOnes(VWidth)); if (Value *V = SimplifyDemandedVectorElts(II, AllOnesEltMask, PoisonElts)) { if (V != II) return replaceInstUsesWith(*II, V); return II; } } if (II->isCommutative()) { if (auto Pair = matchSymmetricPair(II->getOperand(0), II->getOperand(1))) { replaceOperand(*II, 0, Pair->first); replaceOperand(*II, 1, Pair->second); return II; } if (CallInst *NewCall = canonicalizeConstantArg0ToArg1(CI)) return NewCall; } // Unused constrained FP intrinsic calls may have declared side effect, which // prevents it from being removed. In some cases however the side effect is // actually absent. To detect this case, call SimplifyConstrainedFPCall. If it // returns a replacement, the call may be removed. if (CI.use_empty() && isa(CI)) { if (simplifyConstrainedFPCall(&CI, SQ.getWithInstruction(&CI))) return eraseInstFromFunction(CI); } Intrinsic::ID IID = II->getIntrinsicID(); switch (IID) { case Intrinsic::objectsize: { SmallVector InsertedInstructions; if (Value *V = lowerObjectSizeCall(II, DL, &TLI, AA, /*MustSucceed=*/false, &InsertedInstructions)) { for (Instruction *Inserted : InsertedInstructions) Worklist.add(Inserted); return replaceInstUsesWith(CI, V); } return nullptr; } case Intrinsic::abs: { Value *IIOperand = II->getArgOperand(0); bool IntMinIsPoison = cast(II->getArgOperand(1))->isOneValue(); // abs(-x) -> abs(x) // TODO: Copy nsw if it was present on the neg? Value *X; if (match(IIOperand, m_Neg(m_Value(X)))) return replaceOperand(*II, 0, X); if (match(IIOperand, m_Select(m_Value(), m_Value(X), m_Neg(m_Deferred(X))))) return replaceOperand(*II, 0, X); if (match(IIOperand, m_Select(m_Value(), m_Neg(m_Value(X)), m_Deferred(X)))) return replaceOperand(*II, 0, X); Value *Y; // abs(a * abs(b)) -> abs(a * b) if (match(IIOperand, m_OneUse(m_c_Mul(m_Value(X), m_Intrinsic(m_Value(Y)))))) { bool NSW = cast(IIOperand)->hasNoSignedWrap() && IntMinIsPoison; auto *XY = NSW ? Builder.CreateNSWMul(X, Y) : Builder.CreateMul(X, Y); return replaceOperand(*II, 0, XY); } if (std::optional Known = getKnownSignOrZero(IIOperand, SQ.getWithInstruction(II))) { // abs(x) -> x if x >= 0 (include abs(x-y) --> x - y where x >= y) // abs(x) -> x if x > 0 (include abs(x-y) --> x - y where x > y) if (!*Known) return replaceInstUsesWith(*II, IIOperand); // abs(x) -> -x if x < 0 // abs(x) -> -x if x < = 0 (include abs(x-y) --> y - x where x <= y) if (IntMinIsPoison) return BinaryOperator::CreateNSWNeg(IIOperand); return BinaryOperator::CreateNeg(IIOperand); } // abs (sext X) --> zext (abs X*) // Clear the IsIntMin (nsw) bit on the abs to allow narrowing. if (match(IIOperand, m_OneUse(m_SExt(m_Value(X))))) { Value *NarrowAbs = Builder.CreateBinaryIntrinsic(Intrinsic::abs, X, Builder.getFalse()); return CastInst::Create(Instruction::ZExt, NarrowAbs, II->getType()); } // Match a complicated way to check if a number is odd/even: // abs (srem X, 2) --> and X, 1 const APInt *C; if (match(IIOperand, m_SRem(m_Value(X), m_APInt(C))) && *C == 2) return BinaryOperator::CreateAnd(X, ConstantInt::get(II->getType(), 1)); break; } case Intrinsic::umin: { Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); // umin(x, 1) == zext(x != 0) if (match(I1, m_One())) { assert(II->getType()->getScalarSizeInBits() != 1 && "Expected simplify of umin with max constant"); Value *Zero = Constant::getNullValue(I0->getType()); Value *Cmp = Builder.CreateICmpNE(I0, Zero); return CastInst::Create(Instruction::ZExt, Cmp, II->getType()); } // umin(cttz(x), const) --> cttz(x | (1 << const)) if (Value *FoldedCttz = foldMinimumOverTrailingOrLeadingZeroCount( I0, I1, DL, Builder)) return replaceInstUsesWith(*II, FoldedCttz); // umin(ctlz(x), const) --> ctlz(x | (SignedMin >> const)) if (Value *FoldedCtlz = foldMinimumOverTrailingOrLeadingZeroCount( I0, I1, DL, Builder)) return replaceInstUsesWith(*II, FoldedCtlz); [[fallthrough]]; } case Intrinsic::umax: { Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); Value *X, *Y; if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_ZExt(m_Value(Y))) && (I0->hasOneUse() || I1->hasOneUse()) && X->getType() == Y->getType()) { Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, Y); return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType()); } Constant *C; if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_Constant(C)) && I0->hasOneUse()) { if (Constant *NarrowC = getLosslessUnsignedTrunc(C, X->getType())) { Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC); return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType()); } } // If both operands of unsigned min/max are sign-extended, it is still ok // to narrow the operation. [[fallthrough]]; } case Intrinsic::smax: case Intrinsic::smin: { Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1); Value *X, *Y; if (match(I0, m_SExt(m_Value(X))) && match(I1, m_SExt(m_Value(Y))) && (I0->hasOneUse() || I1->hasOneUse()) && X->getType() == Y->getType()) { Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, Y); return CastInst::Create(Instruction::SExt, NarrowMaxMin, II->getType()); } Constant *C; if (match(I0, m_SExt(m_Value(X))) && match(I1, m_Constant(C)) && I0->hasOneUse()) { if (Constant *NarrowC = getLosslessSignedTrunc(C, X->getType())) { Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC); return CastInst::Create(Instruction::SExt, NarrowMaxMin, II->getType()); } } // umin(i1 X, i1 Y) -> and i1 X, Y // smax(i1 X, i1 Y) -> and i1 X, Y if ((IID == Intrinsic::umin || IID == Intrinsic::smax) && II->getType()->isIntOrIntVectorTy(1)) { return BinaryOperator::CreateAnd(I0, I1); } // umax(i1 X, i1 Y) -> or i1 X, Y // smin(i1 X, i1 Y) -> or i1 X, Y if ((IID == Intrinsic::umax || IID == Intrinsic::smin) && II->getType()->isIntOrIntVectorTy(1)) { return BinaryOperator::CreateOr(I0, I1); } if (IID == Intrinsic::smax || IID == Intrinsic::smin) { // smax (neg nsw X), (neg nsw Y) --> neg nsw (smin X, Y) // smin (neg nsw X), (neg nsw Y) --> neg nsw (smax X, Y) // TODO: Canonicalize neg after min/max if I1 is constant. if (match(I0, m_NSWNeg(m_Value(X))) && match(I1, m_NSWNeg(m_Value(Y))) && (I0->hasOneUse() || I1->hasOneUse())) { Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID); Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, Y); return BinaryOperator::CreateNSWNeg(InvMaxMin); } } // (umax X, (xor X, Pow2)) // -> (or X, Pow2) // (umin X, (xor X, Pow2)) // -> (and X, ~Pow2) // (smax X, (xor X, Pos_Pow2)) // -> (or X, Pos_Pow2) // (smin X, (xor X, Pos_Pow2)) // -> (and X, ~Pos_Pow2) // (smax X, (xor X, Neg_Pow2)) // -> (and X, ~Neg_Pow2) // (smin X, (xor X, Neg_Pow2)) // -> (or X, Neg_Pow2) if ((match(I0, m_c_Xor(m_Specific(I1), m_Value(X))) || match(I1, m_c_Xor(m_Specific(I0), m_Value(X)))) && isKnownToBeAPowerOfTwo(X, /* OrZero */ true)) { bool UseOr = IID == Intrinsic::smax || IID == Intrinsic::umax; bool UseAndN = IID == Intrinsic::smin || IID == Intrinsic::umin; if (IID == Intrinsic::smax || IID == Intrinsic::smin) { auto KnownSign = getKnownSign(X, SQ.getWithInstruction(II)); if (KnownSign == std::nullopt) { UseOr = false; UseAndN = false; } else if (*KnownSign /* true is Signed. */) { UseOr ^= true; UseAndN ^= true; Type *Ty = I0->getType(); // Negative power of 2 must be IntMin. It's possible to be able to // prove negative / power of 2 without actually having known bits, so // just get the value by hand. X = Constant::getIntegerValue( Ty, APInt::getSignedMinValue(Ty->getScalarSizeInBits())); } } if (UseOr) return BinaryOperator::CreateOr(I0, X); else if (UseAndN) return BinaryOperator::CreateAnd(I0, Builder.CreateNot(X)); } // If we can eliminate ~A and Y is free to invert: // max ~A, Y --> ~(min A, ~Y) // // Examples: // max ~A, ~Y --> ~(min A, Y) // max ~A, C --> ~(min A, ~C) // max ~A, (max ~Y, ~Z) --> ~min( A, (min Y, Z)) auto moveNotAfterMinMax = [&](Value *X, Value *Y) -> Instruction * { Value *A; if (match(X, m_OneUse(m_Not(m_Value(A)))) && !isFreeToInvert(A, A->hasOneUse())) { if (Value *NotY = getFreelyInverted(Y, Y->hasOneUse(), &Builder)) { Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID); Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, A, NotY); return BinaryOperator::CreateNot(InvMaxMin); } } return nullptr; }; if (Instruction *I = moveNotAfterMinMax(I0, I1)) return I; if (Instruction *I = moveNotAfterMinMax(I1, I0)) return I; if (Instruction *I = moveAddAfterMinMax(II, Builder)) return I; // minmax (X & NegPow2C, Y & NegPow2C) --> minmax(X, Y) & NegPow2C const APInt *RHSC; if (match(I0, m_OneUse(m_And(m_Value(X), m_NegatedPower2(RHSC)))) && match(I1, m_OneUse(m_And(m_Value(Y), m_SpecificInt(*RHSC))))) return BinaryOperator::CreateAnd(Builder.CreateBinaryIntrinsic(IID, X, Y), ConstantInt::get(II->getType(), *RHSC)); // smax(X, -X) --> abs(X) // smin(X, -X) --> -abs(X) // umax(X, -X) --> -abs(X) // umin(X, -X) --> abs(X) if (isKnownNegation(I0, I1)) { // We can choose either operand as the input to abs(), but if we can // eliminate the only use of a value, that's better for subsequent // transforms/analysis. if (I0->hasOneUse() && !I1->hasOneUse()) std::swap(I0, I1); // This is some variant of abs(). See if we can propagate 'nsw' to the abs // operation and potentially its negation. bool IntMinIsPoison = isKnownNegation(I0, I1, /* NeedNSW */ true); Value *Abs = Builder.CreateBinaryIntrinsic( Intrinsic::abs, I0, ConstantInt::getBool(II->getContext(), IntMinIsPoison)); // We don't have a "nabs" intrinsic, so negate if needed based on the // max/min operation. if (IID == Intrinsic::smin || IID == Intrinsic::umax) Abs = Builder.CreateNeg(Abs, "nabs", IntMinIsPoison); return replaceInstUsesWith(CI, Abs); } if (Instruction *Sel = foldClampRangeOfTwo(II, Builder)) return Sel; if (Instruction *SAdd = matchSAddSubSat(*II)) return SAdd; if (Value *NewMinMax = reassociateMinMaxWithConstants(II, Builder, SQ)) return replaceInstUsesWith(*II, NewMinMax); if (Instruction *R = reassociateMinMaxWithConstantInOperand(II, Builder)) return R; if (Instruction *NewMinMax = factorizeMinMaxTree(II)) return NewMinMax; // Try to fold minmax with constant RHS based on range information if (match(I1, m_APIntAllowPoison(RHSC))) { ICmpInst::Predicate Pred = ICmpInst::getNonStrictPredicate(MinMaxIntrinsic::getPredicate(IID)); bool IsSigned = MinMaxIntrinsic::isSigned(IID); ConstantRange LHS_CR = computeConstantRangeIncludingKnownBits( I0, IsSigned, SQ.getWithInstruction(II)); if (!LHS_CR.isFullSet()) { if (LHS_CR.icmp(Pred, *RHSC)) return replaceInstUsesWith(*II, I0); if (LHS_CR.icmp(ICmpInst::getSwappedPredicate(Pred), *RHSC)) return replaceInstUsesWith(*II, ConstantInt::get(II->getType(), *RHSC)); } } break; } case Intrinsic::bitreverse: { Value *IIOperand = II->getArgOperand(0); // bitrev (zext i1 X to ?) --> X ? SignBitC : 0 Value *X; if (match(IIOperand, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) { Type *Ty = II->getType(); APInt SignBit = APInt::getSignMask(Ty->getScalarSizeInBits()); return SelectInst::Create(X, ConstantInt::get(Ty, SignBit), ConstantInt::getNullValue(Ty)); } if (Instruction *crossLogicOpFold = foldBitOrderCrossLogicOp(IIOperand, Builder)) return crossLogicOpFold; break; } case Intrinsic::bswap: { Value *IIOperand = II->getArgOperand(0); // Try to canonicalize bswap-of-logical-shift-by-8-bit-multiple as // inverse-shift-of-bswap: // bswap (shl X, Y) --> lshr (bswap X), Y // bswap (lshr X, Y) --> shl (bswap X), Y Value *X, *Y; if (match(IIOperand, m_OneUse(m_LogicalShift(m_Value(X), m_Value(Y))))) { unsigned BitWidth = IIOperand->getType()->getScalarSizeInBits(); if (MaskedValueIsZero(Y, APInt::getLowBitsSet(BitWidth, 3))) { Value *NewSwap = Builder.CreateUnaryIntrinsic(Intrinsic::bswap, X); BinaryOperator::BinaryOps InverseShift = cast(IIOperand)->getOpcode() == Instruction::Shl ? Instruction::LShr : Instruction::Shl; return BinaryOperator::Create(InverseShift, NewSwap, Y); } } KnownBits Known = computeKnownBits(IIOperand, 0, II); uint64_t LZ = alignDown(Known.countMinLeadingZeros(), 8); uint64_t TZ = alignDown(Known.countMinTrailingZeros(), 8); unsigned BW = Known.getBitWidth(); // bswap(x) -> shift(x) if x has exactly one "active byte" if (BW - LZ - TZ == 8) { assert(LZ != TZ && "active byte cannot be in the middle"); if (LZ > TZ) // -> shl(x) if the "active byte" is in the low part of x return BinaryOperator::CreateNUWShl( IIOperand, ConstantInt::get(IIOperand->getType(), LZ - TZ)); // -> lshr(x) if the "active byte" is in the high part of x return BinaryOperator::CreateExactLShr( IIOperand, ConstantInt::get(IIOperand->getType(), TZ - LZ)); } // bswap(trunc(bswap(x))) -> trunc(lshr(x, c)) if (match(IIOperand, m_Trunc(m_BSwap(m_Value(X))))) { unsigned C = X->getType()->getScalarSizeInBits() - BW; Value *CV = ConstantInt::get(X->getType(), C); Value *V = Builder.CreateLShr(X, CV); return new TruncInst(V, IIOperand->getType()); } if (Instruction *crossLogicOpFold = foldBitOrderCrossLogicOp(IIOperand, Builder)) { return crossLogicOpFold; } // Try to fold into bitreverse if bswap is the root of the expression tree. if (Instruction *BitOp = matchBSwapOrBitReverse(*II, /*MatchBSwaps*/ false, /*MatchBitReversals*/ true)) return BitOp; break; } case Intrinsic::masked_load: if (Value *SimplifiedMaskedOp = simplifyMaskedLoad(*II)) return replaceInstUsesWith(CI, SimplifiedMaskedOp); break; case Intrinsic::masked_store: return simplifyMaskedStore(*II); case Intrinsic::masked_gather: return simplifyMaskedGather(*II); case Intrinsic::masked_scatter: return simplifyMaskedScatter(*II); case Intrinsic::launder_invariant_group: case Intrinsic::strip_invariant_group: if (auto *SkippedBarrier = simplifyInvariantGroupIntrinsic(*II, *this)) return replaceInstUsesWith(*II, SkippedBarrier); break; case Intrinsic::powi: if (ConstantInt *Power = dyn_cast(II->getArgOperand(1))) { // 0 and 1 are handled in instsimplify // powi(x, -1) -> 1/x if (Power->isMinusOne()) return BinaryOperator::CreateFDivFMF(ConstantFP::get(CI.getType(), 1.0), II->getArgOperand(0), II); // powi(x, 2) -> x*x if (Power->equalsInt(2)) return BinaryOperator::CreateFMulFMF(II->getArgOperand(0), II->getArgOperand(0), II); if (!Power->getValue()[0]) { Value *X; // If power is even: // powi(-x, p) -> powi(x, p) // powi(fabs(x), p) -> powi(x, p) // powi(copysign(x, y), p) -> powi(x, p) if (match(II->getArgOperand(0), m_FNeg(m_Value(X))) || match(II->getArgOperand(0), m_FAbs(m_Value(X))) || match(II->getArgOperand(0), m_Intrinsic(m_Value(X), m_Value()))) return replaceOperand(*II, 0, X); } } break; case Intrinsic::cttz: case Intrinsic::ctlz: if (auto *I = foldCttzCtlz(*II, *this)) return I; break; case Intrinsic::ctpop: if (auto *I = foldCtpop(*II, *this)) return I; break; case Intrinsic::fshl: case Intrinsic::fshr: { Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1); Type *Ty = II->getType(); unsigned BitWidth = Ty->getScalarSizeInBits(); Constant *ShAmtC; if (match(II->getArgOperand(2), m_ImmConstant(ShAmtC))) { // Canonicalize a shift amount constant operand to modulo the bit-width. Constant *WidthC = ConstantInt::get(Ty, BitWidth); Constant *ModuloC = ConstantFoldBinaryOpOperands(Instruction::URem, ShAmtC, WidthC, DL); if (!ModuloC) return nullptr; if (ModuloC != ShAmtC) return replaceOperand(*II, 2, ModuloC); assert(match(ConstantFoldCompareInstOperands(ICmpInst::ICMP_UGT, WidthC, ShAmtC, DL), m_One()) && "Shift amount expected to be modulo bitwidth"); // Canonicalize funnel shift right by constant to funnel shift left. This // is not entirely arbitrary. For historical reasons, the backend may // recognize rotate left patterns but miss rotate right patterns. if (IID == Intrinsic::fshr) { // fshr X, Y, C --> fshl X, Y, (BitWidth - C) if C is not zero. if (!isKnownNonZero(ShAmtC, SQ.getWithInstruction(II))) return nullptr; Constant *LeftShiftC = ConstantExpr::getSub(WidthC, ShAmtC); Module *Mod = II->getModule(); Function *Fshl = Intrinsic::getDeclaration(Mod, Intrinsic::fshl, Ty); return CallInst::Create(Fshl, { Op0, Op1, LeftShiftC }); } assert(IID == Intrinsic::fshl && "All funnel shifts by simple constants should go left"); // fshl(X, 0, C) --> shl X, C // fshl(X, undef, C) --> shl X, C if (match(Op1, m_ZeroInt()) || match(Op1, m_Undef())) return BinaryOperator::CreateShl(Op0, ShAmtC); // fshl(0, X, C) --> lshr X, (BW-C) // fshl(undef, X, C) --> lshr X, (BW-C) if (match(Op0, m_ZeroInt()) || match(Op0, m_Undef())) return BinaryOperator::CreateLShr(Op1, ConstantExpr::getSub(WidthC, ShAmtC)); // fshl i16 X, X, 8 --> bswap i16 X (reduce to more-specific form) if (Op0 == Op1 && BitWidth == 16 && match(ShAmtC, m_SpecificInt(8))) { Module *Mod = II->getModule(); Function *Bswap = Intrinsic::getDeclaration(Mod, Intrinsic::bswap, Ty); return CallInst::Create(Bswap, { Op0 }); } if (Instruction *BitOp = matchBSwapOrBitReverse(*II, /*MatchBSwaps*/ true, /*MatchBitReversals*/ true)) return BitOp; } // Left or right might be masked. if (SimplifyDemandedInstructionBits(*II)) return &CI; // The shift amount (operand 2) of a funnel shift is modulo the bitwidth, // so only the low bits of the shift amount are demanded if the bitwidth is // a power-of-2. if (!isPowerOf2_32(BitWidth)) break; APInt Op2Demanded = APInt::getLowBitsSet(BitWidth, Log2_32_Ceil(BitWidth)); KnownBits Op2Known(BitWidth); if (SimplifyDemandedBits(II, 2, Op2Demanded, Op2Known)) return &CI; break; } case Intrinsic::ptrmask: { unsigned BitWidth = DL.getPointerTypeSizeInBits(II->getType()); KnownBits Known(BitWidth); if (SimplifyDemandedInstructionBits(*II, Known)) return II; Value *InnerPtr, *InnerMask; bool Changed = false; // Combine: // (ptrmask (ptrmask p, A), B) // -> (ptrmask p, (and A, B)) if (match(II->getArgOperand(0), m_OneUse(m_Intrinsic(m_Value(InnerPtr), m_Value(InnerMask))))) { assert(II->getArgOperand(1)->getType() == InnerMask->getType() && "Mask types must match"); // TODO: If InnerMask == Op1, we could copy attributes from inner // callsite -> outer callsite. Value *NewMask = Builder.CreateAnd(II->getArgOperand(1), InnerMask); replaceOperand(CI, 0, InnerPtr); replaceOperand(CI, 1, NewMask); Changed = true; } // See if we can deduce non-null. if (!CI.hasRetAttr(Attribute::NonNull) && (Known.isNonZero() || isKnownNonZero(II, getSimplifyQuery().getWithInstruction(II)))) { CI.addRetAttr(Attribute::NonNull); Changed = true; } unsigned NewAlignmentLog = std::min(Value::MaxAlignmentExponent, std::min(BitWidth - 1, Known.countMinTrailingZeros())); // Known bits will capture if we had alignment information associated with // the pointer argument. if (NewAlignmentLog > Log2(CI.getRetAlign().valueOrOne())) { CI.addRetAttr(Attribute::getWithAlignment( CI.getContext(), Align(uint64_t(1) << NewAlignmentLog))); Changed = true; } if (Changed) return &CI; break; } case Intrinsic::uadd_with_overflow: case Intrinsic::sadd_with_overflow: { if (Instruction *I = foldIntrinsicWithOverflowCommon(II)) return I; // Given 2 constant operands whose sum does not overflow: // uaddo (X +nuw C0), C1 -> uaddo X, C0 + C1 // saddo (X +nsw C0), C1 -> saddo X, C0 + C1 Value *X; const APInt *C0, *C1; Value *Arg0 = II->getArgOperand(0); Value *Arg1 = II->getArgOperand(1); bool IsSigned = IID == Intrinsic::sadd_with_overflow; bool HasNWAdd = IsSigned ? match(Arg0, m_NSWAddLike(m_Value(X), m_APInt(C0))) : match(Arg0, m_NUWAddLike(m_Value(X), m_APInt(C0))); if (HasNWAdd && match(Arg1, m_APInt(C1))) { bool Overflow; APInt NewC = IsSigned ? C1->sadd_ov(*C0, Overflow) : C1->uadd_ov(*C0, Overflow); if (!Overflow) return replaceInstUsesWith( *II, Builder.CreateBinaryIntrinsic( IID, X, ConstantInt::get(Arg1->getType(), NewC))); } break; } case Intrinsic::umul_with_overflow: case Intrinsic::smul_with_overflow: case Intrinsic::usub_with_overflow: if (Instruction *I = foldIntrinsicWithOverflowCommon(II)) return I; break; case Intrinsic::ssub_with_overflow: { if (Instruction *I = foldIntrinsicWithOverflowCommon(II)) return I; Constant *C; Value *Arg0 = II->getArgOperand(0); Value *Arg1 = II->getArgOperand(1); // Given a constant C that is not the minimum signed value // for an integer of a given bit width: // // ssubo X, C -> saddo X, -C if (match(Arg1, m_Constant(C)) && C->isNotMinSignedValue()) { Value *NegVal = ConstantExpr::getNeg(C); // Build a saddo call that is equivalent to the discovered // ssubo call. return replaceInstUsesWith( *II, Builder.CreateBinaryIntrinsic(Intrinsic::sadd_with_overflow, Arg0, NegVal)); } break; } case Intrinsic::uadd_sat: case Intrinsic::sadd_sat: case Intrinsic::usub_sat: case Intrinsic::ssub_sat: { SaturatingInst *SI = cast(II); Type *Ty = SI->getType(); Value *Arg0 = SI->getLHS(); Value *Arg1 = SI->getRHS(); // Make use of known overflow information. OverflowResult OR = computeOverflow(SI->getBinaryOp(), SI->isSigned(), Arg0, Arg1, SI); switch (OR) { case OverflowResult::MayOverflow: break; case OverflowResult::NeverOverflows: if (SI->isSigned()) return BinaryOperator::CreateNSW(SI->getBinaryOp(), Arg0, Arg1); else return BinaryOperator::CreateNUW(SI->getBinaryOp(), Arg0, Arg1); case OverflowResult::AlwaysOverflowsLow: { unsigned BitWidth = Ty->getScalarSizeInBits(); APInt Min = APSInt::getMinValue(BitWidth, !SI->isSigned()); return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Min)); } case OverflowResult::AlwaysOverflowsHigh: { unsigned BitWidth = Ty->getScalarSizeInBits(); APInt Max = APSInt::getMaxValue(BitWidth, !SI->isSigned()); return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Max)); } } // usub_sat((sub nuw C, A), C1) -> usub_sat(usub_sat(C, C1), A) // which after that: // usub_sat((sub nuw C, A), C1) -> usub_sat(C - C1, A) if C1 u< C // usub_sat((sub nuw C, A), C1) -> 0 otherwise Constant *C, *C1; Value *A; if (IID == Intrinsic::usub_sat && match(Arg0, m_NUWSub(m_ImmConstant(C), m_Value(A))) && match(Arg1, m_ImmConstant(C1))) { auto *NewC = Builder.CreateBinaryIntrinsic(Intrinsic::usub_sat, C, C1); auto *NewSub = Builder.CreateBinaryIntrinsic(Intrinsic::usub_sat, NewC, A); return replaceInstUsesWith(*SI, NewSub); } // ssub.sat(X, C) -> sadd.sat(X, -C) if C != MIN if (IID == Intrinsic::ssub_sat && match(Arg1, m_Constant(C)) && C->isNotMinSignedValue()) { Value *NegVal = ConstantExpr::getNeg(C); return replaceInstUsesWith( *II, Builder.CreateBinaryIntrinsic( Intrinsic::sadd_sat, Arg0, NegVal)); } // sat(sat(X + Val2) + Val) -> sat(X + (Val+Val2)) // sat(sat(X - Val2) - Val) -> sat(X - (Val+Val2)) // if Val and Val2 have the same sign if (auto *Other = dyn_cast(Arg0)) { Value *X; const APInt *Val, *Val2; APInt NewVal; bool IsUnsigned = IID == Intrinsic::uadd_sat || IID == Intrinsic::usub_sat; if (Other->getIntrinsicID() == IID && match(Arg1, m_APInt(Val)) && match(Other->getArgOperand(0), m_Value(X)) && match(Other->getArgOperand(1), m_APInt(Val2))) { if (IsUnsigned) NewVal = Val->uadd_sat(*Val2); else if (Val->isNonNegative() == Val2->isNonNegative()) { bool Overflow; NewVal = Val->sadd_ov(*Val2, Overflow); if (Overflow) { // Both adds together may add more than SignedMaxValue // without saturating the final result. break; } } else { // Cannot fold saturated addition with different signs. break; } return replaceInstUsesWith( *II, Builder.CreateBinaryIntrinsic( IID, X, ConstantInt::get(II->getType(), NewVal))); } } break; } case Intrinsic::minnum: case Intrinsic::maxnum: case Intrinsic::minimum: case Intrinsic::maximum: { Value *Arg0 = II->getArgOperand(0); Value *Arg1 = II->getArgOperand(1); Value *X, *Y; if (match(Arg0, m_FNeg(m_Value(X))) && match(Arg1, m_FNeg(m_Value(Y))) && (Arg0->hasOneUse() || Arg1->hasOneUse())) { // If both operands are negated, invert the call and negate the result: // min(-X, -Y) --> -(max(X, Y)) // max(-X, -Y) --> -(min(X, Y)) Intrinsic::ID NewIID; switch (IID) { case Intrinsic::maxnum: NewIID = Intrinsic::minnum; break; case Intrinsic::minnum: NewIID = Intrinsic::maxnum; break; case Intrinsic::maximum: NewIID = Intrinsic::minimum; break; case Intrinsic::minimum: NewIID = Intrinsic::maximum; break; default: llvm_unreachable("unexpected intrinsic ID"); } Value *NewCall = Builder.CreateBinaryIntrinsic(NewIID, X, Y, II); Instruction *FNeg = UnaryOperator::CreateFNeg(NewCall); FNeg->copyIRFlags(II); return FNeg; } // m(m(X, C2), C1) -> m(X, C) const APFloat *C1, *C2; if (auto *M = dyn_cast(Arg0)) { if (M->getIntrinsicID() == IID && match(Arg1, m_APFloat(C1)) && ((match(M->getArgOperand(0), m_Value(X)) && match(M->getArgOperand(1), m_APFloat(C2))) || (match(M->getArgOperand(1), m_Value(X)) && match(M->getArgOperand(0), m_APFloat(C2))))) { APFloat Res(0.0); switch (IID) { case Intrinsic::maxnum: Res = maxnum(*C1, *C2); break; case Intrinsic::minnum: Res = minnum(*C1, *C2); break; case Intrinsic::maximum: Res = maximum(*C1, *C2); break; case Intrinsic::minimum: Res = minimum(*C1, *C2); break; default: llvm_unreachable("unexpected intrinsic ID"); } Value *V = Builder.CreateBinaryIntrinsic( IID, X, ConstantFP::get(Arg0->getType(), Res), II); // TODO: Conservatively intersecting FMF. If Res == C2, the transform // was a simplification (so Arg0 and its original flags could // propagate?) if (auto *CI = dyn_cast(V)) CI->andIRFlags(M); return replaceInstUsesWith(*II, V); } } // m((fpext X), (fpext Y)) -> fpext (m(X, Y)) if (match(Arg0, m_OneUse(m_FPExt(m_Value(X)))) && match(Arg1, m_OneUse(m_FPExt(m_Value(Y)))) && X->getType() == Y->getType()) { Value *NewCall = Builder.CreateBinaryIntrinsic(IID, X, Y, II, II->getName()); return new FPExtInst(NewCall, II->getType()); } // max X, -X --> fabs X // min X, -X --> -(fabs X) // TODO: Remove one-use limitation? That is obviously better for max, // hence why we don't check for one-use for that. However, // it would be an extra instruction for min (fnabs), but // that is still likely better for analysis and codegen. auto IsMinMaxOrXNegX = [IID, &X](Value *Op0, Value *Op1) { if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_Specific(X))) return Op0->hasOneUse() || (IID != Intrinsic::minimum && IID != Intrinsic::minnum); return false; }; if (IsMinMaxOrXNegX(Arg0, Arg1) || IsMinMaxOrXNegX(Arg1, Arg0)) { Value *R = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, II); if (IID == Intrinsic::minimum || IID == Intrinsic::minnum) R = Builder.CreateFNegFMF(R, II); return replaceInstUsesWith(*II, R); } break; } case Intrinsic::matrix_multiply: { // Optimize negation in matrix multiplication. // -A * -B -> A * B Value *A, *B; if (match(II->getArgOperand(0), m_FNeg(m_Value(A))) && match(II->getArgOperand(1), m_FNeg(m_Value(B)))) { replaceOperand(*II, 0, A); replaceOperand(*II, 1, B); return II; } Value *Op0 = II->getOperand(0); Value *Op1 = II->getOperand(1); Value *OpNotNeg, *NegatedOp; unsigned NegatedOpArg, OtherOpArg; if (match(Op0, m_FNeg(m_Value(OpNotNeg)))) { NegatedOp = Op0; NegatedOpArg = 0; OtherOpArg = 1; } else if (match(Op1, m_FNeg(m_Value(OpNotNeg)))) { NegatedOp = Op1; NegatedOpArg = 1; OtherOpArg = 0; } else // Multiplication doesn't have a negated operand. break; // Only optimize if the negated operand has only one use. if (!NegatedOp->hasOneUse()) break; Value *OtherOp = II->getOperand(OtherOpArg); VectorType *RetTy = cast(II->getType()); VectorType *NegatedOpTy = cast(NegatedOp->getType()); VectorType *OtherOpTy = cast(OtherOp->getType()); ElementCount NegatedCount = NegatedOpTy->getElementCount(); ElementCount OtherCount = OtherOpTy->getElementCount(); ElementCount RetCount = RetTy->getElementCount(); // (-A) * B -> A * (-B), if it is cheaper to negate B and vice versa. if (ElementCount::isKnownGT(NegatedCount, OtherCount) && ElementCount::isKnownLT(OtherCount, RetCount)) { Value *InverseOtherOp = Builder.CreateFNeg(OtherOp); replaceOperand(*II, NegatedOpArg, OpNotNeg); replaceOperand(*II, OtherOpArg, InverseOtherOp); return II; } // (-A) * B -> -(A * B), if it is cheaper to negate the result if (ElementCount::isKnownGT(NegatedCount, RetCount)) { SmallVector NewArgs(II->args()); NewArgs[NegatedOpArg] = OpNotNeg; Instruction *NewMul = Builder.CreateIntrinsic(II->getType(), IID, NewArgs, II); return replaceInstUsesWith(*II, Builder.CreateFNegFMF(NewMul, II)); } break; } case Intrinsic::fmuladd: { // Try to simplify the underlying FMul. if (Value *V = simplifyFMulInst(II->getArgOperand(0), II->getArgOperand(1), II->getFastMathFlags(), SQ.getWithInstruction(II))) { auto *FAdd = BinaryOperator::CreateFAdd(V, II->getArgOperand(2)); FAdd->copyFastMathFlags(II); return FAdd; } [[fallthrough]]; } case Intrinsic::fma: { // fma fneg(x), fneg(y), z -> fma x, y, z Value *Src0 = II->getArgOperand(0); Value *Src1 = II->getArgOperand(1); Value *X, *Y; if (match(Src0, m_FNeg(m_Value(X))) && match(Src1, m_FNeg(m_Value(Y)))) { replaceOperand(*II, 0, X); replaceOperand(*II, 1, Y); return II; } // fma fabs(x), fabs(x), z -> fma x, x, z if (match(Src0, m_FAbs(m_Value(X))) && match(Src1, m_FAbs(m_Specific(X)))) { replaceOperand(*II, 0, X); replaceOperand(*II, 1, X); return II; } // Try to simplify the underlying FMul. We can only apply simplifications // that do not require rounding. if (Value *V = simplifyFMAFMul(II->getArgOperand(0), II->getArgOperand(1), II->getFastMathFlags(), SQ.getWithInstruction(II))) { auto *FAdd = BinaryOperator::CreateFAdd(V, II->getArgOperand(2)); FAdd->copyFastMathFlags(II); return FAdd; } // fma x, y, 0 -> fmul x, y // This is always valid for -0.0, but requires nsz for +0.0 as // -0.0 + 0.0 = 0.0, which would not be the same as the fmul on its own. if (match(II->getArgOperand(2), m_NegZeroFP()) || (match(II->getArgOperand(2), m_PosZeroFP()) && II->getFastMathFlags().noSignedZeros())) return BinaryOperator::CreateFMulFMF(Src0, Src1, II); break; } case Intrinsic::copysign: { Value *Mag = II->getArgOperand(0), *Sign = II->getArgOperand(1); if (std::optional KnownSignBit = computeKnownFPSignBit( Sign, /*Depth=*/0, getSimplifyQuery().getWithInstruction(II))) { if (*KnownSignBit) { // If we know that the sign argument is negative, reduce to FNABS: // copysign Mag, -Sign --> fneg (fabs Mag) Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Mag, II); return replaceInstUsesWith(*II, Builder.CreateFNegFMF(Fabs, II)); } // If we know that the sign argument is positive, reduce to FABS: // copysign Mag, +Sign --> fabs Mag Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Mag, II); return replaceInstUsesWith(*II, Fabs); } // Propagate sign argument through nested calls: // copysign Mag, (copysign ?, X) --> copysign Mag, X Value *X; if (match(Sign, m_Intrinsic(m_Value(), m_Value(X)))) return replaceOperand(*II, 1, X); // Clear sign-bit of constant magnitude: // copysign -MagC, X --> copysign MagC, X // TODO: Support constant folding for fabs const APFloat *MagC; if (match(Mag, m_APFloat(MagC)) && MagC->isNegative()) { APFloat PosMagC = *MagC; PosMagC.clearSign(); return replaceOperand(*II, 0, ConstantFP::get(Mag->getType(), PosMagC)); } // Peek through changes of magnitude's sign-bit. This call rewrites those: // copysign (fabs X), Sign --> copysign X, Sign // copysign (fneg X), Sign --> copysign X, Sign if (match(Mag, m_FAbs(m_Value(X))) || match(Mag, m_FNeg(m_Value(X)))) return replaceOperand(*II, 0, X); break; } case Intrinsic::fabs: { Value *Cond, *TVal, *FVal; Value *Arg = II->getArgOperand(0); Value *X; // fabs (-X) --> fabs (X) if (match(Arg, m_FNeg(m_Value(X)))) { CallInst *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, II); return replaceInstUsesWith(CI, Fabs); } if (match(Arg, m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))) { // fabs (select Cond, TrueC, FalseC) --> select Cond, AbsT, AbsF if (isa(TVal) || isa(FVal)) { CallInst *AbsT = Builder.CreateCall(II->getCalledFunction(), {TVal}); CallInst *AbsF = Builder.CreateCall(II->getCalledFunction(), {FVal}); SelectInst *SI = SelectInst::Create(Cond, AbsT, AbsF); FastMathFlags FMF1 = II->getFastMathFlags(); FastMathFlags FMF2 = cast(Arg)->getFastMathFlags(); FMF2.setNoSignedZeros(false); SI->setFastMathFlags(FMF1 | FMF2); return SI; } // fabs (select Cond, -FVal, FVal) --> fabs FVal if (match(TVal, m_FNeg(m_Specific(FVal)))) return replaceOperand(*II, 0, FVal); // fabs (select Cond, TVal, -TVal) --> fabs TVal if (match(FVal, m_FNeg(m_Specific(TVal)))) return replaceOperand(*II, 0, TVal); } Value *Magnitude, *Sign; if (match(II->getArgOperand(0), m_CopySign(m_Value(Magnitude), m_Value(Sign)))) { // fabs (copysign x, y) -> (fabs x) CallInst *AbsSign = Builder.CreateCall(II->getCalledFunction(), {Magnitude}); AbsSign->copyFastMathFlags(II); return replaceInstUsesWith(*II, AbsSign); } [[fallthrough]]; } case Intrinsic::ceil: case Intrinsic::floor: case Intrinsic::round: case Intrinsic::roundeven: case Intrinsic::nearbyint: case Intrinsic::rint: case Intrinsic::trunc: { Value *ExtSrc; if (match(II->getArgOperand(0), m_OneUse(m_FPExt(m_Value(ExtSrc))))) { // Narrow the call: intrinsic (fpext x) -> fpext (intrinsic x) Value *NarrowII = Builder.CreateUnaryIntrinsic(IID, ExtSrc, II); return new FPExtInst(NarrowII, II->getType()); } break; } case Intrinsic::cos: case Intrinsic::amdgcn_cos: { Value *X, *Sign; Value *Src = II->getArgOperand(0); if (match(Src, m_FNeg(m_Value(X))) || match(Src, m_FAbs(m_Value(X))) || match(Src, m_CopySign(m_Value(X), m_Value(Sign)))) { // cos(-x) --> cos(x) // cos(fabs(x)) --> cos(x) // cos(copysign(x, y)) --> cos(x) return replaceOperand(*II, 0, X); } break; } case Intrinsic::sin: case Intrinsic::amdgcn_sin: { Value *X; if (match(II->getArgOperand(0), m_OneUse(m_FNeg(m_Value(X))))) { // sin(-x) --> -sin(x) Value *NewSin = Builder.CreateUnaryIntrinsic(IID, X, II); return UnaryOperator::CreateFNegFMF(NewSin, II); } break; } case Intrinsic::ldexp: { // ldexp(ldexp(x, a), b) -> ldexp(x, a + b) // // The danger is if the first ldexp would overflow to infinity or underflow // to zero, but the combined exponent avoids it. We ignore this with // reassoc. // // It's also safe to fold if we know both exponents are >= 0 or <= 0 since // it would just double down on the overflow/underflow which would occur // anyway. // // TODO: Could do better if we had range tracking for the input value // exponent. Also could broaden sign check to cover == 0 case. Value *Src = II->getArgOperand(0); Value *Exp = II->getArgOperand(1); Value *InnerSrc; Value *InnerExp; if (match(Src, m_OneUse(m_Intrinsic( m_Value(InnerSrc), m_Value(InnerExp)))) && Exp->getType() == InnerExp->getType()) { FastMathFlags FMF = II->getFastMathFlags(); FastMathFlags InnerFlags = cast(Src)->getFastMathFlags(); if ((FMF.allowReassoc() && InnerFlags.allowReassoc()) || signBitMustBeTheSame(Exp, InnerExp, SQ.getWithInstruction(II))) { // TODO: Add nsw/nuw probably safe if integer type exceeds exponent // width. Value *NewExp = Builder.CreateAdd(InnerExp, Exp); II->setArgOperand(1, NewExp); II->setFastMathFlags(InnerFlags); // Or the inner flags. return replaceOperand(*II, 0, InnerSrc); } } // ldexp(x, zext(i1 y)) -> fmul x, (select y, 2.0, 1.0) // ldexp(x, sext(i1 y)) -> fmul x, (select y, 0.5, 1.0) Value *ExtSrc; if (match(Exp, m_ZExt(m_Value(ExtSrc))) && ExtSrc->getType()->getScalarSizeInBits() == 1) { Value *Select = Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 2.0), ConstantFP::get(II->getType(), 1.0)); return BinaryOperator::CreateFMulFMF(Src, Select, II); } if (match(Exp, m_SExt(m_Value(ExtSrc))) && ExtSrc->getType()->getScalarSizeInBits() == 1) { Value *Select = Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 0.5), ConstantFP::get(II->getType(), 1.0)); return BinaryOperator::CreateFMulFMF(Src, Select, II); } // ldexp(x, c ? exp : 0) -> c ? ldexp(x, exp) : x // ldexp(x, c ? 0 : exp) -> c ? x : ldexp(x, exp) /// // TODO: If we cared, should insert a canonicalize for x Value *SelectCond, *SelectLHS, *SelectRHS; if (match(II->getArgOperand(1), m_OneUse(m_Select(m_Value(SelectCond), m_Value(SelectLHS), m_Value(SelectRHS))))) { Value *NewLdexp = nullptr; Value *Select = nullptr; if (match(SelectRHS, m_ZeroInt())) { NewLdexp = Builder.CreateLdexp(Src, SelectLHS); Select = Builder.CreateSelect(SelectCond, NewLdexp, Src); } else if (match(SelectLHS, m_ZeroInt())) { NewLdexp = Builder.CreateLdexp(Src, SelectRHS); Select = Builder.CreateSelect(SelectCond, Src, NewLdexp); } if (NewLdexp) { Select->takeName(II); cast(NewLdexp)->copyFastMathFlags(II); return replaceInstUsesWith(*II, Select); } } break; } case Intrinsic::ptrauth_auth: case Intrinsic::ptrauth_resign: { // (sign|resign) + (auth|resign) can be folded by omitting the middle // sign+auth component if the key and discriminator match. bool NeedSign = II->getIntrinsicID() == Intrinsic::ptrauth_resign; Value *Ptr = II->getArgOperand(0); Value *Key = II->getArgOperand(1); Value *Disc = II->getArgOperand(2); // AuthKey will be the key we need to end up authenticating against in // whatever we replace this sequence with. Value *AuthKey = nullptr, *AuthDisc = nullptr, *BasePtr; if (const auto *CI = dyn_cast(Ptr)) { BasePtr = CI->getArgOperand(0); if (CI->getIntrinsicID() == Intrinsic::ptrauth_sign) { if (CI->getArgOperand(1) != Key || CI->getArgOperand(2) != Disc) break; } else if (CI->getIntrinsicID() == Intrinsic::ptrauth_resign) { if (CI->getArgOperand(3) != Key || CI->getArgOperand(4) != Disc) break; AuthKey = CI->getArgOperand(1); AuthDisc = CI->getArgOperand(2); } else break; } else if (const auto *PtrToInt = dyn_cast(Ptr)) { // ptrauth constants are equivalent to a call to @llvm.ptrauth.sign for // our purposes, so check for that too. const auto *CPA = dyn_cast(PtrToInt->getOperand(0)); if (!CPA || !CPA->isKnownCompatibleWith(Key, Disc, DL)) break; // resign(ptrauth(p,ks,ds),ks,ds,kr,dr) -> ptrauth(p,kr,dr) if (NeedSign && isa(II->getArgOperand(4))) { auto *SignKey = cast(II->getArgOperand(3)); auto *SignDisc = cast(II->getArgOperand(4)); auto *SignAddrDisc = ConstantPointerNull::get(Builder.getPtrTy()); auto *NewCPA = ConstantPtrAuth::get(CPA->getPointer(), SignKey, SignDisc, SignAddrDisc); replaceInstUsesWith( *II, ConstantExpr::getPointerCast(NewCPA, II->getType())); return eraseInstFromFunction(*II); } // auth(ptrauth(p,k,d),k,d) -> p BasePtr = Builder.CreatePtrToInt(CPA->getPointer(), II->getType()); } else break; unsigned NewIntrin; if (AuthKey && NeedSign) { // resign(0,1) + resign(1,2) = resign(0, 2) NewIntrin = Intrinsic::ptrauth_resign; } else if (AuthKey) { // resign(0,1) + auth(1) = auth(0) NewIntrin = Intrinsic::ptrauth_auth; } else if (NeedSign) { // sign(0) + resign(0, 1) = sign(1) NewIntrin = Intrinsic::ptrauth_sign; } else { // sign(0) + auth(0) = nop replaceInstUsesWith(*II, BasePtr); return eraseInstFromFunction(*II); } SmallVector CallArgs; CallArgs.push_back(BasePtr); if (AuthKey) { CallArgs.push_back(AuthKey); CallArgs.push_back(AuthDisc); } if (NeedSign) { CallArgs.push_back(II->getArgOperand(3)); CallArgs.push_back(II->getArgOperand(4)); } Function *NewFn = Intrinsic::getDeclaration(II->getModule(), NewIntrin); return CallInst::Create(NewFn, CallArgs); } case Intrinsic::arm_neon_vtbl1: case Intrinsic::aarch64_neon_tbl1: if (Value *V = simplifyNeonTbl1(*II, Builder)) return replaceInstUsesWith(*II, V); break; case Intrinsic::arm_neon_vmulls: case Intrinsic::arm_neon_vmullu: case Intrinsic::aarch64_neon_smull: case Intrinsic::aarch64_neon_umull: { Value *Arg0 = II->getArgOperand(0); Value *Arg1 = II->getArgOperand(1); // Handle mul by zero first: if (isa(Arg0) || isa(Arg1)) { return replaceInstUsesWith(CI, ConstantAggregateZero::get(II->getType())); } // Check for constant LHS & RHS - in this case we just simplify. bool Zext = (IID == Intrinsic::arm_neon_vmullu || IID == Intrinsic::aarch64_neon_umull); VectorType *NewVT = cast(II->getType()); if (Constant *CV0 = dyn_cast(Arg0)) { if (Constant *CV1 = dyn_cast(Arg1)) { Value *V0 = Builder.CreateIntCast(CV0, NewVT, /*isSigned=*/!Zext); Value *V1 = Builder.CreateIntCast(CV1, NewVT, /*isSigned=*/!Zext); return replaceInstUsesWith(CI, Builder.CreateMul(V0, V1)); } // Couldn't simplify - canonicalize constant to the RHS. std::swap(Arg0, Arg1); } // Handle mul by one: if (Constant *CV1 = dyn_cast(Arg1)) if (ConstantInt *Splat = dyn_cast_or_null(CV1->getSplatValue())) if (Splat->isOne()) return CastInst::CreateIntegerCast(Arg0, II->getType(), /*isSigned=*/!Zext); break; } case Intrinsic::arm_neon_aesd: case Intrinsic::arm_neon_aese: case Intrinsic::aarch64_crypto_aesd: case Intrinsic::aarch64_crypto_aese: { Value *DataArg = II->getArgOperand(0); Value *KeyArg = II->getArgOperand(1); // Try to use the builtin XOR in AESE and AESD to eliminate a prior XOR Value *Data, *Key; if (match(KeyArg, m_ZeroInt()) && match(DataArg, m_Xor(m_Value(Data), m_Value(Key)))) { replaceOperand(*II, 0, Data); replaceOperand(*II, 1, Key); return II; } break; } case Intrinsic::hexagon_V6_vandvrt: case Intrinsic::hexagon_V6_vandvrt_128B: { // Simplify Q -> V -> Q conversion. if (auto Op0 = dyn_cast(II->getArgOperand(0))) { Intrinsic::ID ID0 = Op0->getIntrinsicID(); if (ID0 != Intrinsic::hexagon_V6_vandqrt && ID0 != Intrinsic::hexagon_V6_vandqrt_128B) break; Value *Bytes = Op0->getArgOperand(1), *Mask = II->getArgOperand(1); uint64_t Bytes1 = computeKnownBits(Bytes, 0, Op0).One.getZExtValue(); uint64_t Mask1 = computeKnownBits(Mask, 0, II).One.getZExtValue(); // Check if every byte has common bits in Bytes and Mask. uint64_t C = Bytes1 & Mask1; if ((C & 0xFF) && (C & 0xFF00) && (C & 0xFF0000) && (C & 0xFF000000)) return replaceInstUsesWith(*II, Op0->getArgOperand(0)); } break; } case Intrinsic::stackrestore: { enum class ClassifyResult { None, Alloca, StackRestore, CallWithSideEffects, }; auto Classify = [](const Instruction *I) { if (isa(I)) return ClassifyResult::Alloca; if (auto *CI = dyn_cast(I)) { if (auto *II = dyn_cast(CI)) { if (II->getIntrinsicID() == Intrinsic::stackrestore) return ClassifyResult::StackRestore; if (II->mayHaveSideEffects()) return ClassifyResult::CallWithSideEffects; } else { // Consider all non-intrinsic calls to be side effects return ClassifyResult::CallWithSideEffects; } } return ClassifyResult::None; }; // If the stacksave and the stackrestore are in the same BB, and there is // no intervening call, alloca, or stackrestore of a different stacksave, // remove the restore. This can happen when variable allocas are DCE'd. if (IntrinsicInst *SS = dyn_cast(II->getArgOperand(0))) { if (SS->getIntrinsicID() == Intrinsic::stacksave && SS->getParent() == II->getParent()) { BasicBlock::iterator BI(SS); bool CannotRemove = false; for (++BI; &*BI != II; ++BI) { switch (Classify(&*BI)) { case ClassifyResult::None: // So far so good, look at next instructions. break; case ClassifyResult::StackRestore: // If we found an intervening stackrestore for a different // stacksave, we can't remove the stackrestore. Otherwise, continue. if (cast(*BI).getArgOperand(0) != SS) CannotRemove = true; break; case ClassifyResult::Alloca: case ClassifyResult::CallWithSideEffects: // If we found an alloca, a non-intrinsic call, or an intrinsic // call with side effects, we can't remove the stackrestore. CannotRemove = true; break; } if (CannotRemove) break; } if (!CannotRemove) return eraseInstFromFunction(CI); } } // Scan down this block to see if there is another stack restore in the // same block without an intervening call/alloca. BasicBlock::iterator BI(II); Instruction *TI = II->getParent()->getTerminator(); bool CannotRemove = false; for (++BI; &*BI != TI; ++BI) { switch (Classify(&*BI)) { case ClassifyResult::None: // So far so good, look at next instructions. break; case ClassifyResult::StackRestore: // If there is a stackrestore below this one, remove this one. return eraseInstFromFunction(CI); case ClassifyResult::Alloca: case ClassifyResult::CallWithSideEffects: // If we found an alloca, a non-intrinsic call, or an intrinsic call // with side effects (such as llvm.stacksave and llvm.read_register), // we can't remove the stack restore. CannotRemove = true; break; } if (CannotRemove) break; } // If the stack restore is in a return, resume, or unwind block and if there // are no allocas or calls between the restore and the return, nuke the // restore. if (!CannotRemove && (isa(TI) || isa(TI))) return eraseInstFromFunction(CI); break; } case Intrinsic::lifetime_end: // Asan needs to poison memory to detect invalid access which is possible // even for empty lifetime range. if (II->getFunction()->hasFnAttribute(Attribute::SanitizeAddress) || II->getFunction()->hasFnAttribute(Attribute::SanitizeMemory) || II->getFunction()->hasFnAttribute(Attribute::SanitizeHWAddress)) break; if (removeTriviallyEmptyRange(*II, *this, [](const IntrinsicInst &I) { return I.getIntrinsicID() == Intrinsic::lifetime_start; })) return nullptr; break; case Intrinsic::assume: { Value *IIOperand = II->getArgOperand(0); SmallVector OpBundles; II->getOperandBundlesAsDefs(OpBundles); /// This will remove the boolean Condition from the assume given as /// argument and remove the assume if it becomes useless. /// always returns nullptr for use as a return values. auto RemoveConditionFromAssume = [&](Instruction *Assume) -> Instruction * { assert(isa(Assume)); if (isAssumeWithEmptyBundle(*cast(II))) return eraseInstFromFunction(CI); replaceUse(II->getOperandUse(0), ConstantInt::getTrue(II->getContext())); return nullptr; }; // Remove an assume if it is followed by an identical assume. // TODO: Do we need this? Unless there are conflicting assumptions, the // computeKnownBits(IIOperand) below here eliminates redundant assumes. Instruction *Next = II->getNextNonDebugInstruction(); if (match(Next, m_Intrinsic(m_Specific(IIOperand)))) return RemoveConditionFromAssume(Next); // Canonicalize assume(a && b) -> assume(a); assume(b); // Note: New assumption intrinsics created here are registered by // the InstCombineIRInserter object. FunctionType *AssumeIntrinsicTy = II->getFunctionType(); Value *AssumeIntrinsic = II->getCalledOperand(); Value *A, *B; if (match(IIOperand, m_LogicalAnd(m_Value(A), m_Value(B)))) { Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, A, OpBundles, II->getName()); Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, B, II->getName()); return eraseInstFromFunction(*II); } // assume(!(a || b)) -> assume(!a); assume(!b); if (match(IIOperand, m_Not(m_LogicalOr(m_Value(A), m_Value(B))))) { Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, Builder.CreateNot(A), OpBundles, II->getName()); Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, Builder.CreateNot(B), II->getName()); return eraseInstFromFunction(*II); } // assume( (load addr) != null ) -> add 'nonnull' metadata to load // (if assume is valid at the load) CmpInst::Predicate Pred; Instruction *LHS; if (match(IIOperand, m_ICmp(Pred, m_Instruction(LHS), m_Zero())) && Pred == ICmpInst::ICMP_NE && LHS->getOpcode() == Instruction::Load && LHS->getType()->isPointerTy() && isValidAssumeForContext(II, LHS, &DT)) { MDNode *MD = MDNode::get(II->getContext(), std::nullopt); LHS->setMetadata(LLVMContext::MD_nonnull, MD); LHS->setMetadata(LLVMContext::MD_noundef, MD); return RemoveConditionFromAssume(II); // TODO: apply nonnull return attributes to calls and invokes // TODO: apply range metadata for range check patterns? } // Separate storage assumptions apply to the underlying allocations, not any // particular pointer within them. When evaluating the hints for AA purposes // we getUnderlyingObject them; by precomputing the answers here we can // avoid having to do so repeatedly there. for (unsigned Idx = 0; Idx < II->getNumOperandBundles(); Idx++) { OperandBundleUse OBU = II->getOperandBundleAt(Idx); if (OBU.getTagName() == "separate_storage") { assert(OBU.Inputs.size() == 2); auto MaybeSimplifyHint = [&](const Use &U) { Value *Hint = U.get(); // Not having a limit is safe because InstCombine removes unreachable // code. Value *UnderlyingObject = getUnderlyingObject(Hint, /*MaxLookup*/ 0); if (Hint != UnderlyingObject) replaceUse(const_cast(U), UnderlyingObject); }; MaybeSimplifyHint(OBU.Inputs[0]); MaybeSimplifyHint(OBU.Inputs[1]); } } // Convert nonnull assume like: // %A = icmp ne i32* %PTR, null // call void @llvm.assume(i1 %A) // into // call void @llvm.assume(i1 true) [ "nonnull"(i32* %PTR) ] if (EnableKnowledgeRetention && match(IIOperand, m_Cmp(Pred, m_Value(A), m_Zero())) && Pred == CmpInst::ICMP_NE && A->getType()->isPointerTy()) { if (auto *Replacement = buildAssumeFromKnowledge( {RetainedKnowledge{Attribute::NonNull, 0, A}}, Next, &AC, &DT)) { Replacement->insertBefore(Next); AC.registerAssumption(Replacement); return RemoveConditionFromAssume(II); } } // Convert alignment assume like: // %B = ptrtoint i32* %A to i64 // %C = and i64 %B, Constant // %D = icmp eq i64 %C, 0 // call void @llvm.assume(i1 %D) // into // call void @llvm.assume(i1 true) [ "align"(i32* [[A]], i64 Constant + 1)] uint64_t AlignMask; if (EnableKnowledgeRetention && match(IIOperand, m_Cmp(Pred, m_And(m_Value(A), m_ConstantInt(AlignMask)), m_Zero())) && Pred == CmpInst::ICMP_EQ) { if (isPowerOf2_64(AlignMask + 1)) { uint64_t Offset = 0; match(A, m_Add(m_Value(A), m_ConstantInt(Offset))); if (match(A, m_PtrToInt(m_Value(A)))) { /// Note: this doesn't preserve the offset information but merges /// offset and alignment. /// TODO: we can generate a GEP instead of merging the alignment with /// the offset. RetainedKnowledge RK{Attribute::Alignment, (unsigned)MinAlign(Offset, AlignMask + 1), A}; if (auto *Replacement = buildAssumeFromKnowledge(RK, Next, &AC, &DT)) { Replacement->insertAfter(II); AC.registerAssumption(Replacement); } return RemoveConditionFromAssume(II); } } } /// Canonicalize Knowledge in operand bundles. if (EnableKnowledgeRetention && II->hasOperandBundles()) { for (unsigned Idx = 0; Idx < II->getNumOperandBundles(); Idx++) { auto &BOI = II->bundle_op_info_begin()[Idx]; RetainedKnowledge RK = llvm::getKnowledgeFromBundle(cast(*II), BOI); if (BOI.End - BOI.Begin > 2) continue; // Prevent reducing knowledge in an align with offset since // extracting a RetainedKnowledge from them looses offset // information RetainedKnowledge CanonRK = llvm::simplifyRetainedKnowledge(cast(II), RK, &getAssumptionCache(), &getDominatorTree()); if (CanonRK == RK) continue; if (!CanonRK) { if (BOI.End - BOI.Begin > 0) { Worklist.pushValue(II->op_begin()[BOI.Begin]); Value::dropDroppableUse(II->op_begin()[BOI.Begin]); } continue; } assert(RK.AttrKind == CanonRK.AttrKind); if (BOI.End - BOI.Begin > 0) II->op_begin()[BOI.Begin].set(CanonRK.WasOn); if (BOI.End - BOI.Begin > 1) II->op_begin()[BOI.Begin + 1].set(ConstantInt::get( Type::getInt64Ty(II->getContext()), CanonRK.ArgValue)); if (RK.WasOn) Worklist.pushValue(RK.WasOn); return II; } } // If there is a dominating assume with the same condition as this one, // then this one is redundant, and should be removed. KnownBits Known(1); computeKnownBits(IIOperand, Known, 0, II); if (Known.isAllOnes() && isAssumeWithEmptyBundle(cast(*II))) return eraseInstFromFunction(*II); // assume(false) is unreachable. if (match(IIOperand, m_CombineOr(m_Zero(), m_Undef()))) { CreateNonTerminatorUnreachable(II); return eraseInstFromFunction(*II); } // Update the cache of affected values for this assumption (we might be // here because we just simplified the condition). AC.updateAffectedValues(cast(II)); break; } case Intrinsic::experimental_guard: { // Is this guard followed by another guard? We scan forward over a small // fixed window of instructions to handle common cases with conditions // computed between guards. Instruction *NextInst = II->getNextNonDebugInstruction(); for (unsigned i = 0; i < GuardWideningWindow; i++) { // Note: Using context-free form to avoid compile time blow up if (!isSafeToSpeculativelyExecute(NextInst)) break; NextInst = NextInst->getNextNonDebugInstruction(); } Value *NextCond = nullptr; if (match(NextInst, m_Intrinsic(m_Value(NextCond)))) { Value *CurrCond = II->getArgOperand(0); // Remove a guard that it is immediately preceded by an identical guard. // Otherwise canonicalize guard(a); guard(b) -> guard(a & b). if (CurrCond != NextCond) { Instruction *MoveI = II->getNextNonDebugInstruction(); while (MoveI != NextInst) { auto *Temp = MoveI; MoveI = MoveI->getNextNonDebugInstruction(); Temp->moveBefore(II); } replaceOperand(*II, 0, Builder.CreateAnd(CurrCond, NextCond)); } eraseInstFromFunction(*NextInst); return II; } break; } case Intrinsic::vector_insert: { Value *Vec = II->getArgOperand(0); Value *SubVec = II->getArgOperand(1); Value *Idx = II->getArgOperand(2); auto *DstTy = dyn_cast(II->getType()); auto *VecTy = dyn_cast(Vec->getType()); auto *SubVecTy = dyn_cast(SubVec->getType()); // Only canonicalize if the destination vector, Vec, and SubVec are all // fixed vectors. if (DstTy && VecTy && SubVecTy) { unsigned DstNumElts = DstTy->getNumElements(); unsigned VecNumElts = VecTy->getNumElements(); unsigned SubVecNumElts = SubVecTy->getNumElements(); unsigned IdxN = cast(Idx)->getZExtValue(); // An insert that entirely overwrites Vec with SubVec is a nop. if (VecNumElts == SubVecNumElts) return replaceInstUsesWith(CI, SubVec); // Widen SubVec into a vector of the same width as Vec, since // shufflevector requires the two input vectors to be the same width. // Elements beyond the bounds of SubVec within the widened vector are // undefined. SmallVector WidenMask; unsigned i; for (i = 0; i != SubVecNumElts; ++i) WidenMask.push_back(i); for (; i != VecNumElts; ++i) WidenMask.push_back(PoisonMaskElem); Value *WidenShuffle = Builder.CreateShuffleVector(SubVec, WidenMask); SmallVector Mask; for (unsigned i = 0; i != IdxN; ++i) Mask.push_back(i); for (unsigned i = DstNumElts; i != DstNumElts + SubVecNumElts; ++i) Mask.push_back(i); for (unsigned i = IdxN + SubVecNumElts; i != DstNumElts; ++i) Mask.push_back(i); Value *Shuffle = Builder.CreateShuffleVector(Vec, WidenShuffle, Mask); return replaceInstUsesWith(CI, Shuffle); } break; } case Intrinsic::vector_extract: { Value *Vec = II->getArgOperand(0); Value *Idx = II->getArgOperand(1); Type *ReturnType = II->getType(); // (extract_vector (insert_vector InsertTuple, InsertValue, InsertIdx), // ExtractIdx) unsigned ExtractIdx = cast(Idx)->getZExtValue(); Value *InsertTuple, *InsertIdx, *InsertValue; if (match(Vec, m_Intrinsic(m_Value(InsertTuple), m_Value(InsertValue), m_Value(InsertIdx))) && InsertValue->getType() == ReturnType) { unsigned Index = cast(InsertIdx)->getZExtValue(); // Case where we get the same index right after setting it. // extract.vector(insert.vector(InsertTuple, InsertValue, Idx), Idx) --> // InsertValue if (ExtractIdx == Index) return replaceInstUsesWith(CI, InsertValue); // If we are getting a different index than what was set in the // insert.vector intrinsic. We can just set the input tuple to the one up // in the chain. extract.vector(insert.vector(InsertTuple, InsertValue, // InsertIndex), ExtractIndex) // --> extract.vector(InsertTuple, ExtractIndex) else return replaceOperand(CI, 0, InsertTuple); } auto *DstTy = dyn_cast(ReturnType); auto *VecTy = dyn_cast(Vec->getType()); if (DstTy && VecTy) { auto DstEltCnt = DstTy->getElementCount(); auto VecEltCnt = VecTy->getElementCount(); unsigned IdxN = cast(Idx)->getZExtValue(); // Extracting the entirety of Vec is a nop. if (DstEltCnt == VecTy->getElementCount()) { replaceInstUsesWith(CI, Vec); return eraseInstFromFunction(CI); } // Only canonicalize to shufflevector if the destination vector and // Vec are fixed vectors. if (VecEltCnt.isScalable() || DstEltCnt.isScalable()) break; SmallVector Mask; for (unsigned i = 0; i != DstEltCnt.getKnownMinValue(); ++i) Mask.push_back(IdxN + i); Value *Shuffle = Builder.CreateShuffleVector(Vec, Mask); return replaceInstUsesWith(CI, Shuffle); } break; } case Intrinsic::vector_reverse: { Value *BO0, *BO1, *X, *Y; Value *Vec = II->getArgOperand(0); if (match(Vec, m_OneUse(m_BinOp(m_Value(BO0), m_Value(BO1))))) { auto *OldBinOp = cast(Vec); if (match(BO0, m_VecReverse(m_Value(X)))) { // rev(binop rev(X), rev(Y)) --> binop X, Y if (match(BO1, m_VecReverse(m_Value(Y)))) return replaceInstUsesWith(CI, BinaryOperator::CreateWithCopiedFlags( OldBinOp->getOpcode(), X, Y, OldBinOp, OldBinOp->getName(), II->getIterator())); // rev(binop rev(X), BO1Splat) --> binop X, BO1Splat if (isSplatValue(BO1)) return replaceInstUsesWith(CI, BinaryOperator::CreateWithCopiedFlags( OldBinOp->getOpcode(), X, BO1, OldBinOp, OldBinOp->getName(), II->getIterator())); } // rev(binop BO0Splat, rev(Y)) --> binop BO0Splat, Y if (match(BO1, m_VecReverse(m_Value(Y))) && isSplatValue(BO0)) return replaceInstUsesWith(CI, BinaryOperator::CreateWithCopiedFlags( OldBinOp->getOpcode(), BO0, Y, OldBinOp, OldBinOp->getName(), II->getIterator())); } // rev(unop rev(X)) --> unop X if (match(Vec, m_OneUse(m_UnOp(m_VecReverse(m_Value(X)))))) { auto *OldUnOp = cast(Vec); auto *NewUnOp = UnaryOperator::CreateWithCopiedFlags( OldUnOp->getOpcode(), X, OldUnOp, OldUnOp->getName(), II->getIterator()); return replaceInstUsesWith(CI, NewUnOp); } break; } case Intrinsic::vector_reduce_or: case Intrinsic::vector_reduce_and: { // Canonicalize logical or/and reductions: // Or reduction for i1 is represented as: // %val = bitcast to iReduxWidth // %res = cmp ne iReduxWidth %val, 0 // And reduction for i1 is represented as: // %val = bitcast to iReduxWidth // %res = cmp eq iReduxWidth %val, 11111 Value *Arg = II->getArgOperand(0); Value *Vect; if (Value *NewOp = simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { replaceUse(II->getOperandUse(0), NewOp); return II; } if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { if (auto *FTy = dyn_cast(Vect->getType())) if (FTy->getElementType() == Builder.getInt1Ty()) { Value *Res = Builder.CreateBitCast( Vect, Builder.getIntNTy(FTy->getNumElements())); if (IID == Intrinsic::vector_reduce_and) { Res = Builder.CreateICmpEQ( Res, ConstantInt::getAllOnesValue(Res->getType())); } else { assert(IID == Intrinsic::vector_reduce_or && "Expected or reduction."); Res = Builder.CreateIsNotNull(Res); } if (Arg != Vect) Res = Builder.CreateCast(cast(Arg)->getOpcode(), Res, II->getType()); return replaceInstUsesWith(CI, Res); } } [[fallthrough]]; } case Intrinsic::vector_reduce_add: { if (IID == Intrinsic::vector_reduce_add) { // Convert vector_reduce_add(ZExt()) to // ZExtOrTrunc(ctpop(bitcast to in)). // Convert vector_reduce_add(SExt()) to // -ZExtOrTrunc(ctpop(bitcast to in)). // Convert vector_reduce_add() to // Trunc(ctpop(bitcast to in)). Value *Arg = II->getArgOperand(0); Value *Vect; if (Value *NewOp = simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { replaceUse(II->getOperandUse(0), NewOp); return II; } if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { if (auto *FTy = dyn_cast(Vect->getType())) if (FTy->getElementType() == Builder.getInt1Ty()) { Value *V = Builder.CreateBitCast( Vect, Builder.getIntNTy(FTy->getNumElements())); Value *Res = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, V); if (Res->getType() != II->getType()) Res = Builder.CreateZExtOrTrunc(Res, II->getType()); if (Arg != Vect && cast(Arg)->getOpcode() == Instruction::SExt) Res = Builder.CreateNeg(Res); return replaceInstUsesWith(CI, Res); } } } [[fallthrough]]; } case Intrinsic::vector_reduce_xor: { if (IID == Intrinsic::vector_reduce_xor) { // Exclusive disjunction reduction over the vector with // (potentially-extended) i1 element type is actually a // (potentially-extended) arithmetic `add` reduction over the original // non-extended value: // vector_reduce_xor(?ext()) // --> // ?ext(vector_reduce_add()) Value *Arg = II->getArgOperand(0); Value *Vect; if (Value *NewOp = simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { replaceUse(II->getOperandUse(0), NewOp); return II; } if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { if (auto *VTy = dyn_cast(Vect->getType())) if (VTy->getElementType() == Builder.getInt1Ty()) { Value *Res = Builder.CreateAddReduce(Vect); if (Arg != Vect) Res = Builder.CreateCast(cast(Arg)->getOpcode(), Res, II->getType()); return replaceInstUsesWith(CI, Res); } } } [[fallthrough]]; } case Intrinsic::vector_reduce_mul: { if (IID == Intrinsic::vector_reduce_mul) { // Multiplicative reduction over the vector with (potentially-extended) // i1 element type is actually a (potentially zero-extended) // logical `and` reduction over the original non-extended value: // vector_reduce_mul(?ext()) // --> // zext(vector_reduce_and()) Value *Arg = II->getArgOperand(0); Value *Vect; if (Value *NewOp = simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { replaceUse(II->getOperandUse(0), NewOp); return II; } if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { if (auto *VTy = dyn_cast(Vect->getType())) if (VTy->getElementType() == Builder.getInt1Ty()) { Value *Res = Builder.CreateAndReduce(Vect); if (Res->getType() != II->getType()) Res = Builder.CreateZExt(Res, II->getType()); return replaceInstUsesWith(CI, Res); } } } [[fallthrough]]; } case Intrinsic::vector_reduce_umin: case Intrinsic::vector_reduce_umax: { if (IID == Intrinsic::vector_reduce_umin || IID == Intrinsic::vector_reduce_umax) { // UMin/UMax reduction over the vector with (potentially-extended) // i1 element type is actually a (potentially-extended) // logical `and`/`or` reduction over the original non-extended value: // vector_reduce_u{min,max}(?ext()) // --> // ?ext(vector_reduce_{and,or}()) Value *Arg = II->getArgOperand(0); Value *Vect; if (Value *NewOp = simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { replaceUse(II->getOperandUse(0), NewOp); return II; } if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { if (auto *VTy = dyn_cast(Vect->getType())) if (VTy->getElementType() == Builder.getInt1Ty()) { Value *Res = IID == Intrinsic::vector_reduce_umin ? Builder.CreateAndReduce(Vect) : Builder.CreateOrReduce(Vect); if (Arg != Vect) Res = Builder.CreateCast(cast(Arg)->getOpcode(), Res, II->getType()); return replaceInstUsesWith(CI, Res); } } } [[fallthrough]]; } case Intrinsic::vector_reduce_smin: case Intrinsic::vector_reduce_smax: { if (IID == Intrinsic::vector_reduce_smin || IID == Intrinsic::vector_reduce_smax) { // SMin/SMax reduction over the vector with (potentially-extended) // i1 element type is actually a (potentially-extended) // logical `and`/`or` reduction over the original non-extended value: // vector_reduce_s{min,max}() // --> // vector_reduce_{or,and}() // and // vector_reduce_s{min,max}(sext()) // --> // sext(vector_reduce_{or,and}()) // and // vector_reduce_s{min,max}(zext()) // --> // zext(vector_reduce_{and,or}()) Value *Arg = II->getArgOperand(0); Value *Vect; if (Value *NewOp = simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) { replaceUse(II->getOperandUse(0), NewOp); return II; } if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) { if (auto *VTy = dyn_cast(Vect->getType())) if (VTy->getElementType() == Builder.getInt1Ty()) { Instruction::CastOps ExtOpc = Instruction::CastOps::CastOpsEnd; if (Arg != Vect) ExtOpc = cast(Arg)->getOpcode(); Value *Res = ((IID == Intrinsic::vector_reduce_smin) == (ExtOpc == Instruction::CastOps::ZExt)) ? Builder.CreateAndReduce(Vect) : Builder.CreateOrReduce(Vect); if (Arg != Vect) Res = Builder.CreateCast(ExtOpc, Res, II->getType()); return replaceInstUsesWith(CI, Res); } } } [[fallthrough]]; } case Intrinsic::vector_reduce_fmax: case Intrinsic::vector_reduce_fmin: case Intrinsic::vector_reduce_fadd: case Intrinsic::vector_reduce_fmul: { bool CanReorderLanes = (IID != Intrinsic::vector_reduce_fadd && IID != Intrinsic::vector_reduce_fmul) || II->hasAllowReassoc(); const unsigned ArgIdx = (IID == Intrinsic::vector_reduce_fadd || IID == Intrinsic::vector_reduce_fmul) ? 1 : 0; Value *Arg = II->getArgOperand(ArgIdx); if (Value *NewOp = simplifyReductionOperand(Arg, CanReorderLanes)) { replaceUse(II->getOperandUse(ArgIdx), NewOp); return nullptr; } break; } case Intrinsic::is_fpclass: { if (Instruction *I = foldIntrinsicIsFPClass(*II)) return I; break; } case Intrinsic::threadlocal_address: { Align MinAlign = getKnownAlignment(II->getArgOperand(0), DL, II, &AC, &DT); MaybeAlign Align = II->getRetAlign(); if (MinAlign > Align.valueOrOne()) { II->addRetAttr(Attribute::getWithAlignment(II->getContext(), MinAlign)); return II; } break; } default: { // Handle target specific intrinsics std::optional V = targetInstCombineIntrinsic(*II); if (V) return *V; break; } } // Try to fold intrinsic into select operands. This is legal if: // * The intrinsic is speculatable. // * The select condition is not a vector, or the intrinsic does not // perform cross-lane operations. switch (IID) { case Intrinsic::ctlz: case Intrinsic::cttz: case Intrinsic::ctpop: case Intrinsic::umin: case Intrinsic::umax: case Intrinsic::smin: case Intrinsic::smax: case Intrinsic::usub_sat: case Intrinsic::uadd_sat: case Intrinsic::ssub_sat: case Intrinsic::sadd_sat: for (Value *Op : II->args()) if (auto *Sel = dyn_cast(Op)) if (Instruction *R = FoldOpIntoSelect(*II, Sel)) return R; [[fallthrough]]; default: break; } if (Instruction *Shuf = foldShuffledIntrinsicOperands(II, Builder)) return Shuf; // Some intrinsics (like experimental_gc_statepoint) can be used in invoke // context, so it is handled in visitCallBase and we should trigger it. return visitCallBase(*II); } // Fence instruction simplification Instruction *InstCombinerImpl::visitFenceInst(FenceInst &FI) { auto *NFI = dyn_cast(FI.getNextNonDebugInstruction()); // This check is solely here to handle arbitrary target-dependent syncscopes. // TODO: Can remove if does not matter in practice. if (NFI && FI.isIdenticalTo(NFI)) return eraseInstFromFunction(FI); // Returns true if FI1 is identical or stronger fence than FI2. auto isIdenticalOrStrongerFence = [](FenceInst *FI1, FenceInst *FI2) { auto FI1SyncScope = FI1->getSyncScopeID(); // Consider same scope, where scope is global or single-thread. if (FI1SyncScope != FI2->getSyncScopeID() || (FI1SyncScope != SyncScope::System && FI1SyncScope != SyncScope::SingleThread)) return false; return isAtLeastOrStrongerThan(FI1->getOrdering(), FI2->getOrdering()); }; if (NFI && isIdenticalOrStrongerFence(NFI, &FI)) return eraseInstFromFunction(FI); if (auto *PFI = dyn_cast_or_null(FI.getPrevNonDebugInstruction())) if (isIdenticalOrStrongerFence(PFI, &FI)) return eraseInstFromFunction(FI); return nullptr; } // InvokeInst simplification Instruction *InstCombinerImpl::visitInvokeInst(InvokeInst &II) { return visitCallBase(II); } // CallBrInst simplification Instruction *InstCombinerImpl::visitCallBrInst(CallBrInst &CBI) { return visitCallBase(CBI); } Instruction *InstCombinerImpl::tryOptimizeCall(CallInst *CI) { if (!CI->getCalledFunction()) return nullptr; // Skip optimizing notail and musttail calls so // LibCallSimplifier::optimizeCall doesn't have to preserve those invariants. // LibCallSimplifier::optimizeCall should try to preseve tail calls though. if (CI->isMustTailCall() || CI->isNoTailCall()) return nullptr; auto InstCombineRAUW = [this](Instruction *From, Value *With) { replaceInstUsesWith(*From, With); }; auto InstCombineErase = [this](Instruction *I) { eraseInstFromFunction(*I); }; LibCallSimplifier Simplifier(DL, &TLI, &AC, ORE, BFI, PSI, InstCombineRAUW, InstCombineErase); if (Value *With = Simplifier.optimizeCall(CI, Builder)) { ++NumSimplified; return CI->use_empty() ? CI : replaceInstUsesWith(*CI, With); } return nullptr; } static IntrinsicInst *findInitTrampolineFromAlloca(Value *TrampMem) { // Strip off at most one level of pointer casts, looking for an alloca. This // is good enough in practice and simpler than handling any number of casts. Value *Underlying = TrampMem->stripPointerCasts(); if (Underlying != TrampMem && (!Underlying->hasOneUse() || Underlying->user_back() != TrampMem)) return nullptr; if (!isa(Underlying)) return nullptr; IntrinsicInst *InitTrampoline = nullptr; for (User *U : TrampMem->users()) { IntrinsicInst *II = dyn_cast(U); if (!II) return nullptr; if (II->getIntrinsicID() == Intrinsic::init_trampoline) { if (InitTrampoline) // More than one init_trampoline writes to this value. Give up. return nullptr; InitTrampoline = II; continue; } if (II->getIntrinsicID() == Intrinsic::adjust_trampoline) // Allow any number of calls to adjust.trampoline. continue; return nullptr; } // No call to init.trampoline found. if (!InitTrampoline) return nullptr; // Check that the alloca is being used in the expected way. if (InitTrampoline->getOperand(0) != TrampMem) return nullptr; return InitTrampoline; } static IntrinsicInst *findInitTrampolineFromBB(IntrinsicInst *AdjustTramp, Value *TrampMem) { // Visit all the previous instructions in the basic block, and try to find a // init.trampoline which has a direct path to the adjust.trampoline. for (BasicBlock::iterator I = AdjustTramp->getIterator(), E = AdjustTramp->getParent()->begin(); I != E;) { Instruction *Inst = &*--I; if (IntrinsicInst *II = dyn_cast(I)) if (II->getIntrinsicID() == Intrinsic::init_trampoline && II->getOperand(0) == TrampMem) return II; if (Inst->mayWriteToMemory()) return nullptr; } return nullptr; } // Given a call to llvm.adjust.trampoline, find and return the corresponding // call to llvm.init.trampoline if the call to the trampoline can be optimized // to a direct call to a function. Otherwise return NULL. static IntrinsicInst *findInitTrampoline(Value *Callee) { Callee = Callee->stripPointerCasts(); IntrinsicInst *AdjustTramp = dyn_cast(Callee); if (!AdjustTramp || AdjustTramp->getIntrinsicID() != Intrinsic::adjust_trampoline) return nullptr; Value *TrampMem = AdjustTramp->getOperand(0); if (IntrinsicInst *IT = findInitTrampolineFromAlloca(TrampMem)) return IT; if (IntrinsicInst *IT = findInitTrampolineFromBB(AdjustTramp, TrampMem)) return IT; return nullptr; } bool InstCombinerImpl::annotateAnyAllocSite(CallBase &Call, const TargetLibraryInfo *TLI) { // Note: We only handle cases which can't be driven from generic attributes // here. So, for example, nonnull and noalias (which are common properties // of some allocation functions) are expected to be handled via annotation // of the respective allocator declaration with generic attributes. bool Changed = false; if (!Call.getType()->isPointerTy()) return Changed; std::optional Size = getAllocSize(&Call, TLI); if (Size && *Size != 0) { // TODO: We really should just emit deref_or_null here and then // let the generic inference code combine that with nonnull. if (Call.hasRetAttr(Attribute::NonNull)) { Changed = !Call.hasRetAttr(Attribute::Dereferenceable); Call.addRetAttr(Attribute::getWithDereferenceableBytes( Call.getContext(), Size->getLimitedValue())); } else { Changed = !Call.hasRetAttr(Attribute::DereferenceableOrNull); Call.addRetAttr(Attribute::getWithDereferenceableOrNullBytes( Call.getContext(), Size->getLimitedValue())); } } // Add alignment attribute if alignment is a power of two constant. Value *Alignment = getAllocAlignment(&Call, TLI); if (!Alignment) return Changed; ConstantInt *AlignOpC = dyn_cast(Alignment); if (AlignOpC && AlignOpC->getValue().ult(llvm::Value::MaximumAlignment)) { uint64_t AlignmentVal = AlignOpC->getZExtValue(); if (llvm::isPowerOf2_64(AlignmentVal)) { Align ExistingAlign = Call.getRetAlign().valueOrOne(); Align NewAlign = Align(AlignmentVal); if (NewAlign > ExistingAlign) { Call.addRetAttr( Attribute::getWithAlignment(Call.getContext(), NewAlign)); Changed = true; } } } return Changed; } /// Improvements for call, callbr and invoke instructions. Instruction *InstCombinerImpl::visitCallBase(CallBase &Call) { bool Changed = annotateAnyAllocSite(Call, &TLI); // Mark any parameters that are known to be non-null with the nonnull // attribute. This is helpful for inlining calls to functions with null // checks on their arguments. SmallVector ArgNos; unsigned ArgNo = 0; for (Value *V : Call.args()) { if (V->getType()->isPointerTy() && !Call.paramHasAttr(ArgNo, Attribute::NonNull) && isKnownNonZero(V, getSimplifyQuery().getWithInstruction(&Call))) ArgNos.push_back(ArgNo); ArgNo++; } assert(ArgNo == Call.arg_size() && "Call arguments not processed correctly."); if (!ArgNos.empty()) { AttributeList AS = Call.getAttributes(); LLVMContext &Ctx = Call.getContext(); AS = AS.addParamAttribute(Ctx, ArgNos, Attribute::get(Ctx, Attribute::NonNull)); Call.setAttributes(AS); Changed = true; } // If the callee is a pointer to a function, attempt to move any casts to the // arguments of the call/callbr/invoke. Value *Callee = Call.getCalledOperand(); Function *CalleeF = dyn_cast(Callee); if ((!CalleeF || CalleeF->getFunctionType() != Call.getFunctionType()) && transformConstExprCastCall(Call)) return nullptr; if (CalleeF) { // Remove the convergent attr on calls when the callee is not convergent. if (Call.isConvergent() && !CalleeF->isConvergent() && !CalleeF->isIntrinsic()) { LLVM_DEBUG(dbgs() << "Removing convergent attr from instr " << Call << "\n"); Call.setNotConvergent(); return &Call; } // If the call and callee calling conventions don't match, and neither one // of the calling conventions is compatible with C calling convention // this call must be unreachable, as the call is undefined. if ((CalleeF->getCallingConv() != Call.getCallingConv() && !(CalleeF->getCallingConv() == llvm::CallingConv::C && TargetLibraryInfoImpl::isCallingConvCCompatible(&Call)) && !(Call.getCallingConv() == llvm::CallingConv::C && TargetLibraryInfoImpl::isCallingConvCCompatible(CalleeF))) && // Only do this for calls to a function with a body. A prototype may // not actually end up matching the implementation's calling conv for a // variety of reasons (e.g. it may be written in assembly). !CalleeF->isDeclaration()) { Instruction *OldCall = &Call; CreateNonTerminatorUnreachable(OldCall); // If OldCall does not return void then replaceInstUsesWith poison. // This allows ValueHandlers and custom metadata to adjust itself. if (!OldCall->getType()->isVoidTy()) replaceInstUsesWith(*OldCall, PoisonValue::get(OldCall->getType())); if (isa(OldCall)) return eraseInstFromFunction(*OldCall); // We cannot remove an invoke or a callbr, because it would change thexi // CFG, just change the callee to a null pointer. cast(OldCall)->setCalledFunction( CalleeF->getFunctionType(), Constant::getNullValue(CalleeF->getType())); return nullptr; } } // Calling a null function pointer is undefined if a null address isn't // dereferenceable. if ((isa(Callee) && !NullPointerIsDefined(Call.getFunction())) || isa(Callee)) { // If Call does not return void then replaceInstUsesWith poison. // This allows ValueHandlers and custom metadata to adjust itself. if (!Call.getType()->isVoidTy()) replaceInstUsesWith(Call, PoisonValue::get(Call.getType())); if (Call.isTerminator()) { // Can't remove an invoke or callbr because we cannot change the CFG. return nullptr; } // This instruction is not reachable, just remove it. CreateNonTerminatorUnreachable(&Call); return eraseInstFromFunction(Call); } if (IntrinsicInst *II = findInitTrampoline(Callee)) return transformCallThroughTrampoline(Call, *II); if (isa(Callee) && !Call.doesNotThrow()) { InlineAsm *IA = cast(Callee); if (!IA->canThrow()) { // Normal inline asm calls cannot throw - mark them // 'nounwind'. Call.setDoesNotThrow(); Changed = true; } } // Try to optimize the call if possible, we require DataLayout for most of // this. None of these calls are seen as possibly dead so go ahead and // delete the instruction now. if (CallInst *CI = dyn_cast(&Call)) { Instruction *I = tryOptimizeCall(CI); // If we changed something return the result, etc. Otherwise let // the fallthrough check. if (I) return eraseInstFromFunction(*I); } if (!Call.use_empty() && !Call.isMustTailCall()) if (Value *ReturnedArg = Call.getReturnedArgOperand()) { Type *CallTy = Call.getType(); Type *RetArgTy = ReturnedArg->getType(); if (RetArgTy->canLosslesslyBitCastTo(CallTy)) return replaceInstUsesWith( Call, Builder.CreateBitOrPointerCast(ReturnedArg, CallTy)); } // Drop unnecessary kcfi operand bundles from calls that were converted // into direct calls. auto Bundle = Call.getOperandBundle(LLVMContext::OB_kcfi); if (Bundle && !Call.isIndirectCall()) { DEBUG_WITH_TYPE(DEBUG_TYPE "-kcfi", { if (CalleeF) { ConstantInt *FunctionType = nullptr; ConstantInt *ExpectedType = cast(Bundle->Inputs[0]); if (MDNode *MD = CalleeF->getMetadata(LLVMContext::MD_kcfi_type)) FunctionType = mdconst::extract(MD->getOperand(0)); if (FunctionType && FunctionType->getZExtValue() != ExpectedType->getZExtValue()) dbgs() << Call.getModule()->getName() << ": warning: kcfi: " << Call.getCaller()->getName() << ": call to " << CalleeF->getName() << " using a mismatching function pointer type\n"; } }); return CallBase::removeOperandBundle(&Call, LLVMContext::OB_kcfi); } if (isRemovableAlloc(&Call, &TLI)) return visitAllocSite(Call); // Handle intrinsics which can be used in both call and invoke context. switch (Call.getIntrinsicID()) { case Intrinsic::experimental_gc_statepoint: { GCStatepointInst &GCSP = *cast(&Call); SmallPtrSet LiveGcValues; for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) { GCRelocateInst &GCR = *const_cast(Reloc); // Remove the relocation if unused. if (GCR.use_empty()) { eraseInstFromFunction(GCR); continue; } Value *DerivedPtr = GCR.getDerivedPtr(); Value *BasePtr = GCR.getBasePtr(); // Undef is undef, even after relocation. if (isa(DerivedPtr) || isa(BasePtr)) { replaceInstUsesWith(GCR, UndefValue::get(GCR.getType())); eraseInstFromFunction(GCR); continue; } if (auto *PT = dyn_cast(GCR.getType())) { // The relocation of null will be null for most any collector. // TODO: provide a hook for this in GCStrategy. There might be some // weird collector this property does not hold for. if (isa(DerivedPtr)) { // Use null-pointer of gc_relocate's type to replace it. replaceInstUsesWith(GCR, ConstantPointerNull::get(PT)); eraseInstFromFunction(GCR); continue; } // isKnownNonNull -> nonnull attribute if (!GCR.hasRetAttr(Attribute::NonNull) && isKnownNonZero(DerivedPtr, getSimplifyQuery().getWithInstruction(&Call))) { GCR.addRetAttr(Attribute::NonNull); // We discovered new fact, re-check users. Worklist.pushUsersToWorkList(GCR); } } // If we have two copies of the same pointer in the statepoint argument // list, canonicalize to one. This may let us common gc.relocates. if (GCR.getBasePtr() == GCR.getDerivedPtr() && GCR.getBasePtrIndex() != GCR.getDerivedPtrIndex()) { auto *OpIntTy = GCR.getOperand(2)->getType(); GCR.setOperand(2, ConstantInt::get(OpIntTy, GCR.getBasePtrIndex())); } // TODO: bitcast(relocate(p)) -> relocate(bitcast(p)) // Canonicalize on the type from the uses to the defs // TODO: relocate((gep p, C, C2, ...)) -> gep(relocate(p), C, C2, ...) LiveGcValues.insert(BasePtr); LiveGcValues.insert(DerivedPtr); } std::optional Bundle = GCSP.getOperandBundle(LLVMContext::OB_gc_live); unsigned NumOfGCLives = LiveGcValues.size(); if (!Bundle || NumOfGCLives == Bundle->Inputs.size()) break; // We can reduce the size of gc live bundle. DenseMap Val2Idx; std::vector NewLiveGc; for (Value *V : Bundle->Inputs) { if (Val2Idx.count(V)) continue; if (LiveGcValues.count(V)) { Val2Idx[V] = NewLiveGc.size(); NewLiveGc.push_back(V); } else Val2Idx[V] = NumOfGCLives; } // Update all gc.relocates for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) { GCRelocateInst &GCR = *const_cast(Reloc); Value *BasePtr = GCR.getBasePtr(); assert(Val2Idx.count(BasePtr) && Val2Idx[BasePtr] != NumOfGCLives && "Missed live gc for base pointer"); auto *OpIntTy1 = GCR.getOperand(1)->getType(); GCR.setOperand(1, ConstantInt::get(OpIntTy1, Val2Idx[BasePtr])); Value *DerivedPtr = GCR.getDerivedPtr(); assert(Val2Idx.count(DerivedPtr) && Val2Idx[DerivedPtr] != NumOfGCLives && "Missed live gc for derived pointer"); auto *OpIntTy2 = GCR.getOperand(2)->getType(); GCR.setOperand(2, ConstantInt::get(OpIntTy2, Val2Idx[DerivedPtr])); } // Create new statepoint instruction. OperandBundleDef NewBundle("gc-live", NewLiveGc); return CallBase::Create(&Call, NewBundle); } default: { break; } } return Changed ? &Call : nullptr; } /// If the callee is a constexpr cast of a function, attempt to move the cast to /// the arguments of the call/invoke. /// CallBrInst is not supported. bool InstCombinerImpl::transformConstExprCastCall(CallBase &Call) { auto *Callee = dyn_cast(Call.getCalledOperand()->stripPointerCasts()); if (!Callee) return false; assert(!isa(Call) && "CallBr's don't have a single point after a def to insert at"); // If this is a call to a thunk function, don't remove the cast. Thunks are // used to transparently forward all incoming parameters and outgoing return // values, so it's important to leave the cast in place. if (Callee->hasFnAttribute("thunk")) return false; // If this is a call to a naked function, the assembly might be // using an argument, or otherwise rely on the frame layout, // the function prototype will mismatch. if (Callee->hasFnAttribute(Attribute::Naked)) return false; // If this is a musttail call, the callee's prototype must match the caller's // prototype with the exception of pointee types. The code below doesn't // implement that, so we can't do this transform. // TODO: Do the transform if it only requires adding pointer casts. if (Call.isMustTailCall()) return false; Instruction *Caller = &Call; const AttributeList &CallerPAL = Call.getAttributes(); // Okay, this is a cast from a function to a different type. Unless doing so // would cause a type conversion of one of our arguments, change this call to // be a direct call with arguments casted to the appropriate types. FunctionType *FT = Callee->getFunctionType(); Type *OldRetTy = Caller->getType(); Type *NewRetTy = FT->getReturnType(); // Check to see if we are changing the return type... if (OldRetTy != NewRetTy) { if (NewRetTy->isStructTy()) return false; // TODO: Handle multiple return values. if (!CastInst::isBitOrNoopPointerCastable(NewRetTy, OldRetTy, DL)) { if (Callee->isDeclaration()) return false; // Cannot transform this return value. if (!Caller->use_empty() && // void -> non-void is handled specially !NewRetTy->isVoidTy()) return false; // Cannot transform this return value. } if (!CallerPAL.isEmpty() && !Caller->use_empty()) { AttrBuilder RAttrs(FT->getContext(), CallerPAL.getRetAttrs()); if (RAttrs.overlaps(AttributeFuncs::typeIncompatible(NewRetTy))) return false; // Attribute not compatible with transformed value. } // If the callbase is an invoke instruction, and the return value is // used by a PHI node in a successor, we cannot change the return type of // the call because there is no place to put the cast instruction (without // breaking the critical edge). Bail out in this case. if (!Caller->use_empty()) { BasicBlock *PhisNotSupportedBlock = nullptr; if (auto *II = dyn_cast(Caller)) PhisNotSupportedBlock = II->getNormalDest(); if (PhisNotSupportedBlock) for (User *U : Caller->users()) if (PHINode *PN = dyn_cast(U)) if (PN->getParent() == PhisNotSupportedBlock) return false; } } unsigned NumActualArgs = Call.arg_size(); unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); // Prevent us turning: // declare void @takes_i32_inalloca(i32* inalloca) // call void bitcast (void (i32*)* @takes_i32_inalloca to void (i32)*)(i32 0) // // into: // call void @takes_i32_inalloca(i32* null) // // Similarly, avoid folding away bitcasts of byval calls. if (Callee->getAttributes().hasAttrSomewhere(Attribute::InAlloca) || Callee->getAttributes().hasAttrSomewhere(Attribute::Preallocated)) return false; auto AI = Call.arg_begin(); for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { Type *ParamTy = FT->getParamType(i); Type *ActTy = (*AI)->getType(); if (!CastInst::isBitOrNoopPointerCastable(ActTy, ParamTy, DL)) return false; // Cannot transform this parameter value. // Check if there are any incompatible attributes we cannot drop safely. if (AttrBuilder(FT->getContext(), CallerPAL.getParamAttrs(i)) .overlaps(AttributeFuncs::typeIncompatible( ParamTy, AttributeFuncs::ASK_UNSAFE_TO_DROP))) return false; // Attribute not compatible with transformed value. if (Call.isInAllocaArgument(i) || CallerPAL.hasParamAttr(i, Attribute::Preallocated)) return false; // Cannot transform to and from inalloca/preallocated. if (CallerPAL.hasParamAttr(i, Attribute::SwiftError)) return false; if (CallerPAL.hasParamAttr(i, Attribute::ByVal) != Callee->getAttributes().hasParamAttr(i, Attribute::ByVal)) return false; // Cannot transform to or from byval. } if (Callee->isDeclaration()) { // Do not delete arguments unless we have a function body. if (FT->getNumParams() < NumActualArgs && !FT->isVarArg()) return false; // If the callee is just a declaration, don't change the varargsness of the // call. We don't want to introduce a varargs call where one doesn't // already exist. if (FT->isVarArg() != Call.getFunctionType()->isVarArg()) return false; // If both the callee and the cast type are varargs, we still have to make // sure the number of fixed parameters are the same or we have the same // ABI issues as if we introduce a varargs call. if (FT->isVarArg() && Call.getFunctionType()->isVarArg() && FT->getNumParams() != Call.getFunctionType()->getNumParams()) return false; } if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && !CallerPAL.isEmpty()) { // In this case we have more arguments than the new function type, but we // won't be dropping them. Check that these extra arguments have attributes // that are compatible with being a vararg call argument. unsigned SRetIdx; if (CallerPAL.hasAttrSomewhere(Attribute::StructRet, &SRetIdx) && SRetIdx - AttributeList::FirstArgIndex >= FT->getNumParams()) return false; } // Okay, we decided that this is a safe thing to do: go ahead and start // inserting cast instructions as necessary. SmallVector Args; SmallVector ArgAttrs; Args.reserve(NumActualArgs); ArgAttrs.reserve(NumActualArgs); // Get any return attributes. AttrBuilder RAttrs(FT->getContext(), CallerPAL.getRetAttrs()); // If the return value is not being used, the type may not be compatible // with the existing attributes. Wipe out any problematic attributes. RAttrs.remove(AttributeFuncs::typeIncompatible(NewRetTy)); LLVMContext &Ctx = Call.getContext(); AI = Call.arg_begin(); for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { Type *ParamTy = FT->getParamType(i); Value *NewArg = *AI; if ((*AI)->getType() != ParamTy) NewArg = Builder.CreateBitOrPointerCast(*AI, ParamTy); Args.push_back(NewArg); // Add any parameter attributes except the ones incompatible with the new // type. Note that we made sure all incompatible ones are safe to drop. AttributeMask IncompatibleAttrs = AttributeFuncs::typeIncompatible( ParamTy, AttributeFuncs::ASK_SAFE_TO_DROP); ArgAttrs.push_back( CallerPAL.getParamAttrs(i).removeAttributes(Ctx, IncompatibleAttrs)); } // If the function takes more arguments than the call was taking, add them // now. for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) { Args.push_back(Constant::getNullValue(FT->getParamType(i))); ArgAttrs.push_back(AttributeSet()); } // If we are removing arguments to the function, emit an obnoxious warning. if (FT->getNumParams() < NumActualArgs) { // TODO: if (!FT->isVarArg()) this call may be unreachable. PR14722 if (FT->isVarArg()) { // Add all of the arguments in their promoted form to the arg list. for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { Type *PTy = getPromotedType((*AI)->getType()); Value *NewArg = *AI; if (PTy != (*AI)->getType()) { // Must promote to pass through va_arg area! Instruction::CastOps opcode = CastInst::getCastOpcode(*AI, false, PTy, false); NewArg = Builder.CreateCast(opcode, *AI, PTy); } Args.push_back(NewArg); // Add any parameter attributes. ArgAttrs.push_back(CallerPAL.getParamAttrs(i)); } } } AttributeSet FnAttrs = CallerPAL.getFnAttrs(); if (NewRetTy->isVoidTy()) Caller->setName(""); // Void type should not have a name. assert((ArgAttrs.size() == FT->getNumParams() || FT->isVarArg()) && "missing argument attributes"); AttributeList NewCallerPAL = AttributeList::get( Ctx, FnAttrs, AttributeSet::get(Ctx, RAttrs), ArgAttrs); SmallVector OpBundles; Call.getOperandBundlesAsDefs(OpBundles); CallBase *NewCall; if (InvokeInst *II = dyn_cast(Caller)) { NewCall = Builder.CreateInvoke(Callee, II->getNormalDest(), II->getUnwindDest(), Args, OpBundles); } else { NewCall = Builder.CreateCall(Callee, Args, OpBundles); cast(NewCall)->setTailCallKind( cast(Caller)->getTailCallKind()); } NewCall->takeName(Caller); NewCall->setCallingConv(Call.getCallingConv()); NewCall->setAttributes(NewCallerPAL); // Preserve prof metadata if any. NewCall->copyMetadata(*Caller, {LLVMContext::MD_prof}); // Insert a cast of the return type as necessary. Instruction *NC = NewCall; Value *NV = NC; if (OldRetTy != NV->getType() && !Caller->use_empty()) { if (!NV->getType()->isVoidTy()) { NV = NC = CastInst::CreateBitOrPointerCast(NC, OldRetTy); NC->setDebugLoc(Caller->getDebugLoc()); auto OptInsertPt = NewCall->getInsertionPointAfterDef(); assert(OptInsertPt && "No place to insert cast"); InsertNewInstBefore(NC, *OptInsertPt); Worklist.pushUsersToWorkList(*Caller); } else { NV = PoisonValue::get(Caller->getType()); } } if (!Caller->use_empty()) replaceInstUsesWith(*Caller, NV); else if (Caller->hasValueHandle()) { if (OldRetTy == NV->getType()) ValueHandleBase::ValueIsRAUWd(Caller, NV); else // We cannot call ValueIsRAUWd with a different type, and the // actual tracked value will disappear. ValueHandleBase::ValueIsDeleted(Caller); } eraseInstFromFunction(*Caller); return true; } /// Turn a call to a function created by init_trampoline / adjust_trampoline /// intrinsic pair into a direct call to the underlying function. Instruction * InstCombinerImpl::transformCallThroughTrampoline(CallBase &Call, IntrinsicInst &Tramp) { FunctionType *FTy = Call.getFunctionType(); AttributeList Attrs = Call.getAttributes(); // If the call already has the 'nest' attribute somewhere then give up - // otherwise 'nest' would occur twice after splicing in the chain. if (Attrs.hasAttrSomewhere(Attribute::Nest)) return nullptr; Function *NestF = cast(Tramp.getArgOperand(1)->stripPointerCasts()); FunctionType *NestFTy = NestF->getFunctionType(); AttributeList NestAttrs = NestF->getAttributes(); if (!NestAttrs.isEmpty()) { unsigned NestArgNo = 0; Type *NestTy = nullptr; AttributeSet NestAttr; // Look for a parameter marked with the 'nest' attribute. for (FunctionType::param_iterator I = NestFTy->param_begin(), E = NestFTy->param_end(); I != E; ++NestArgNo, ++I) { AttributeSet AS = NestAttrs.getParamAttrs(NestArgNo); if (AS.hasAttribute(Attribute::Nest)) { // Record the parameter type and any other attributes. NestTy = *I; NestAttr = AS; break; } } if (NestTy) { std::vector NewArgs; std::vector NewArgAttrs; NewArgs.reserve(Call.arg_size() + 1); NewArgAttrs.reserve(Call.arg_size()); // Insert the nest argument into the call argument list, which may // mean appending it. Likewise for attributes. { unsigned ArgNo = 0; auto I = Call.arg_begin(), E = Call.arg_end(); do { if (ArgNo == NestArgNo) { // Add the chain argument and attributes. Value *NestVal = Tramp.getArgOperand(2); if (NestVal->getType() != NestTy) NestVal = Builder.CreateBitCast(NestVal, NestTy, "nest"); NewArgs.push_back(NestVal); NewArgAttrs.push_back(NestAttr); } if (I == E) break; // Add the original argument and attributes. NewArgs.push_back(*I); NewArgAttrs.push_back(Attrs.getParamAttrs(ArgNo)); ++ArgNo; ++I; } while (true); } // The trampoline may have been bitcast to a bogus type (FTy). // Handle this by synthesizing a new function type, equal to FTy // with the chain parameter inserted. std::vector NewTypes; NewTypes.reserve(FTy->getNumParams()+1); // Insert the chain's type into the list of parameter types, which may // mean appending it. { unsigned ArgNo = 0; FunctionType::param_iterator I = FTy->param_begin(), E = FTy->param_end(); do { if (ArgNo == NestArgNo) // Add the chain's type. NewTypes.push_back(NestTy); if (I == E) break; // Add the original type. NewTypes.push_back(*I); ++ArgNo; ++I; } while (true); } // Replace the trampoline call with a direct call. Let the generic // code sort out any function type mismatches. FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, FTy->isVarArg()); AttributeList NewPAL = AttributeList::get(FTy->getContext(), Attrs.getFnAttrs(), Attrs.getRetAttrs(), NewArgAttrs); SmallVector OpBundles; Call.getOperandBundlesAsDefs(OpBundles); Instruction *NewCaller; if (InvokeInst *II = dyn_cast(&Call)) { NewCaller = InvokeInst::Create(NewFTy, NestF, II->getNormalDest(), II->getUnwindDest(), NewArgs, OpBundles); cast(NewCaller)->setCallingConv(II->getCallingConv()); cast(NewCaller)->setAttributes(NewPAL); } else if (CallBrInst *CBI = dyn_cast(&Call)) { NewCaller = CallBrInst::Create(NewFTy, NestF, CBI->getDefaultDest(), CBI->getIndirectDests(), NewArgs, OpBundles); cast(NewCaller)->setCallingConv(CBI->getCallingConv()); cast(NewCaller)->setAttributes(NewPAL); } else { NewCaller = CallInst::Create(NewFTy, NestF, NewArgs, OpBundles); cast(NewCaller)->setTailCallKind( cast(Call).getTailCallKind()); cast(NewCaller)->setCallingConv( cast(Call).getCallingConv()); cast(NewCaller)->setAttributes(NewPAL); } NewCaller->setDebugLoc(Call.getDebugLoc()); return NewCaller; } } // Replace the trampoline call with a direct call. Since there is no 'nest' // parameter, there is no need to adjust the argument list. Let the generic // code sort out any function type mismatches. Call.setCalledFunction(FTy, NestF); return &Call; }