diff options
Diffstat (limited to 'contrib/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 346 |
1 files changed, 210 insertions, 136 deletions
diff --git a/contrib/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/contrib/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp index fd34a244f271..7c46cfd28fc9 100644 --- a/contrib/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/contrib/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -42,8 +42,9 @@ #include "llvm/Analysis/AssumptionCache.h" #include "llvm/Analysis/CFG.h" #include "llvm/Analysis/ConstantFolding.h" +#include "llvm/Analysis/EHPersonalities.h" +#include "llvm/Analysis/GlobalsModRef.h" #include "llvm/Analysis/InstructionSimplify.h" -#include "llvm/Analysis/LibCallSemantics.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/Analysis/MemoryBuiltins.h" #include "llvm/Analysis/TargetLibraryInfo.h" @@ -79,14 +80,12 @@ Value *InstCombiner::EmitGEPOffset(User *GEP) { return llvm::EmitGEPOffset(Builder, DL, GEP); } -/// ShouldChangeType - Return true if it is desirable to convert a computation -/// from 'From' to 'To'. We don't want to convert from a legal to an illegal -/// type for example, or from a smaller to a larger illegal type. -bool InstCombiner::ShouldChangeType(Type *From, Type *To) const { - assert(From->isIntegerTy() && To->isIntegerTy()); - - unsigned FromWidth = From->getPrimitiveSizeInBits(); - unsigned ToWidth = To->getPrimitiveSizeInBits(); +/// Return true if it is desirable to convert an integer computation from a +/// given bit width to a new bit width. +/// We don't want to convert from a legal to an illegal type for example or from +/// a smaller to a larger illegal type. +bool InstCombiner::ShouldChangeType(unsigned FromWidth, + unsigned ToWidth) const { bool FromLegal = DL.isLegalInteger(FromWidth); bool ToLegal = DL.isLegalInteger(ToWidth); @@ -103,6 +102,17 @@ bool InstCombiner::ShouldChangeType(Type *From, Type *To) const { return true; } +/// Return true if it is desirable to convert a computation from 'From' to 'To'. +/// We don't want to convert from a legal to an illegal type for example or from +/// a smaller to a larger illegal type. +bool InstCombiner::ShouldChangeType(Type *From, Type *To) const { + assert(From->isIntegerTy() && To->isIntegerTy()); + + unsigned FromWidth = From->getPrimitiveSizeInBits(); + unsigned ToWidth = To->getPrimitiveSizeInBits(); + return ShouldChangeType(FromWidth, ToWidth); +} + // Return true, if No Signed Wrap should be maintained for I. // The No Signed Wrap flag can be kept if the operation "B (I.getOpcode) C", // where both B and C should be ConstantInts, results in a constant that does @@ -156,27 +166,26 @@ static void ClearSubclassDataAfterReassociation(BinaryOperator &I) { I.setFastMathFlags(FMF); } -/// SimplifyAssociativeOrCommutative - This performs a few simplifications for -/// operators which are associative or commutative: -// -// Commutative operators: -// -// 1. Order operands such that they are listed from right (least complex) to -// left (most complex). This puts constants before unary operators before -// binary operators. -// -// Associative operators: -// -// 2. Transform: "(A op B) op C" ==> "A op (B op C)" if "B op C" simplifies. -// 3. Transform: "A op (B op C)" ==> "(A op B) op C" if "A op B" simplifies. -// -// Associative and commutative operators: -// -// 4. Transform: "(A op B) op C" ==> "(C op A) op B" if "C op A" simplifies. -// 5. Transform: "A op (B op C)" ==> "B op (C op A)" if "C op A" simplifies. -// 6. Transform: "(A op C1) op (B op C2)" ==> "(A op B) op (C1 op C2)" -// if C1 and C2 are constants. -// +/// This performs a few simplifications for operators that are associative or +/// commutative: +/// +/// Commutative operators: +/// +/// 1. Order operands such that they are listed from right (least complex) to +/// left (most complex). This puts constants before unary operators before +/// binary operators. +/// +/// Associative operators: +/// +/// 2. Transform: "(A op B) op C" ==> "A op (B op C)" if "B op C" simplifies. +/// 3. Transform: "A op (B op C)" ==> "(A op B) op C" if "A op B" simplifies. +/// +/// Associative and commutative operators: +/// +/// 4. Transform: "(A op B) op C" ==> "(C op A) op B" if "C op A" simplifies. +/// 5. Transform: "A op (B op C)" ==> "B op (C op A)" if "C op A" simplifies. +/// 6. Transform: "(A op C1) op (B op C2)" ==> "(A op B) op (C1 op C2)" +/// if C1 and C2 are constants. bool InstCombiner::SimplifyAssociativeOrCommutative(BinaryOperator &I) { Instruction::BinaryOps Opcode = I.getOpcode(); bool Changed = false; @@ -322,7 +331,7 @@ bool InstCombiner::SimplifyAssociativeOrCommutative(BinaryOperator &I) { } while (1); } -/// LeftDistributesOverRight - Whether "X LOp (Y ROp Z)" is always equal to +/// Return whether "X LOp (Y ROp Z)" is always equal to /// "(X LOp Y) ROp (X LOp Z)". static bool LeftDistributesOverRight(Instruction::BinaryOps LOp, Instruction::BinaryOps ROp) { @@ -361,7 +370,7 @@ static bool LeftDistributesOverRight(Instruction::BinaryOps LOp, } } -/// RightDistributesOverLeft - Whether "(X LOp Y) ROp Z" is always equal to +/// Return whether "(X LOp Y) ROp Z" is always equal to /// "(X ROp Z) LOp (Y ROp Z)". static bool RightDistributesOverLeft(Instruction::BinaryOps LOp, Instruction::BinaryOps ROp) { @@ -519,7 +528,7 @@ static Value *tryFactorization(InstCombiner::BuilderTy *Builder, if (isa<OverflowingBinaryOperator>(Op1)) HasNSW &= Op1->hasNoSignedWrap(); - // We can propogate 'nsw' if we know that + // We can propagate 'nsw' if we know that // %Y = mul nsw i16 %X, C // %Z = add nsw i16 %Y, %X // => @@ -537,11 +546,11 @@ static Value *tryFactorization(InstCombiner::BuilderTy *Builder, return SimplifiedInst; } -/// SimplifyUsingDistributiveLaws - This tries to simplify binary operations -/// which some other binary operation distributes over either by factorizing -/// out common terms (eg "(A*B)+(A*C)" -> "A*(B+C)") or expanding out if this -/// results in simplifications (eg: "A & (B | C) -> (A&B) | (A&C)" if this is -/// a win). Returns the simplified value, or null if it didn't simplify. +/// This tries to simplify binary operations which some other binary operation +/// distributes over either by factorizing out common terms +/// (eg "(A*B)+(A*C)" -> "A*(B+C)") or expanding out if this results in +/// simplifications (eg: "A & (B | C) -> (A&B) | (A&C)" if this is a win). +/// Returns the simplified value, or null if it didn't simplify. Value *InstCombiner::SimplifyUsingDistributiveLaws(BinaryOperator &I) { Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS); @@ -623,12 +632,38 @@ Value *InstCombiner::SimplifyUsingDistributiveLaws(BinaryOperator &I) { } } + // (op (select (a, c, b)), (select (a, d, b))) -> (select (a, (op c, d), 0)) + // (op (select (a, b, c)), (select (a, b, d))) -> (select (a, 0, (op c, d))) + if (auto *SI0 = dyn_cast<SelectInst>(LHS)) { + if (auto *SI1 = dyn_cast<SelectInst>(RHS)) { + if (SI0->getCondition() == SI1->getCondition()) { + Value *SI = nullptr; + if (Value *V = SimplifyBinOp(TopLevelOpcode, SI0->getFalseValue(), + SI1->getFalseValue(), DL, TLI, DT, AC)) + SI = Builder->CreateSelect(SI0->getCondition(), + Builder->CreateBinOp(TopLevelOpcode, + SI0->getTrueValue(), + SI1->getTrueValue()), + V); + if (Value *V = SimplifyBinOp(TopLevelOpcode, SI0->getTrueValue(), + SI1->getTrueValue(), DL, TLI, DT, AC)) + SI = Builder->CreateSelect( + SI0->getCondition(), V, + Builder->CreateBinOp(TopLevelOpcode, SI0->getFalseValue(), + SI1->getFalseValue())); + if (SI) { + SI->takeName(&I); + return SI; + } + } + } + } + return nullptr; } -// dyn_castNegVal - Given a 'sub' instruction, return the RHS of the instruction -// if the LHS is a constant zero (which is the 'negate' form). -// +/// Given a 'sub' instruction, return the RHS of the instruction if the LHS is a +/// constant zero (which is the 'negate' form). Value *InstCombiner::dyn_castNegVal(Value *V) const { if (BinaryOperator::isNeg(V)) return BinaryOperator::getNegArgument(V); @@ -644,10 +679,8 @@ Value *InstCombiner::dyn_castNegVal(Value *V) const { return nullptr; } -// dyn_castFNegVal - Given a 'fsub' instruction, return the RHS of the -// instruction if the LHS is a constant negative zero (which is the 'negate' -// form). -// +/// Given a 'fsub' instruction, return the RHS of the instruction if the LHS is +/// a constant negative zero (which is the 'negate' form). Value *InstCombiner::dyn_castFNegVal(Value *V, bool IgnoreZeroSign) const { if (BinaryOperator::isFNeg(V, IgnoreZeroSign)) return BinaryOperator::getFNegArgument(V); @@ -700,10 +733,10 @@ static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO, llvm_unreachable("Unknown binary instruction type!"); } -// FoldOpIntoSelect - Given an instruction with a select as one operand and a -// constant as the other operand, try to fold the binary operator into the -// select arguments. This also works for Cast instructions, which obviously do -// not have a second operand. +/// Given an instruction with a select as one operand and a constant as the +/// other operand, try to fold the binary operator into the select arguments. +/// This also works for Cast instructions, which obviously do not have a second +/// operand. Instruction *InstCombiner::FoldOpIntoSelect(Instruction &Op, SelectInst *SI) { // Don't modify shared select instructions if (!SI->hasOneUse()) return nullptr; @@ -752,10 +785,9 @@ Instruction *InstCombiner::FoldOpIntoSelect(Instruction &Op, SelectInst *SI) { return nullptr; } -/// FoldOpIntoPhi - Given a binary operator, cast instruction, or select which -/// has a PHI node as operand #0, see if we can fold the instruction into the -/// PHI (which is only possible if all operands to the PHI are constants). -/// +/// Given a binary operator, cast instruction, or select which has a PHI node as +/// operand #0, see if we can fold the instruction into the PHI (which is only +/// possible if all operands to the PHI are constants). Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) { PHINode *PN = cast<PHINode>(I.getOperand(0)); unsigned NumPHIValues = PN->getNumIncomingValues(); @@ -819,7 +851,7 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) { NewPN->takeName(PN); // If we are going to have to insert a new computation, do so right before the - // predecessors terminator. + // predecessor's terminator. if (NonConstBB) Builder->SetInsertPoint(NonConstBB->getTerminator()); @@ -893,10 +925,10 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) { return ReplaceInstUsesWith(I, NewPN); } -/// FindElementAtOffset - Given a pointer type and a constant offset, determine -/// whether or not there is a sequence of GEP indices into the pointed type that -/// will land us at the specified offset. If so, fill them into NewIndices and -/// return the resultant element type, otherwise return null. +/// Given a pointer type and a constant offset, determine whether or not there +/// is a sequence of GEP indices into the pointed type that will land us at the +/// specified offset. If so, fill them into NewIndices and return the resultant +/// element type, otherwise return null. Type *InstCombiner::FindElementAtOffset(PointerType *PtrTy, int64_t Offset, SmallVectorImpl<Value *> &NewIndices) { Type *Ty = PtrTy->getElementType(); @@ -965,8 +997,8 @@ static bool shouldMergeGEPs(GEPOperator &GEP, GEPOperator &Src) { return true; } -/// Descale - Return a value X such that Val = X * Scale, or null if none. If -/// the multiplication is known not to overflow then NoSignedWrap is set. +/// Return a value X such that Val = X * Scale, or null if none. +/// If the multiplication is known not to overflow, then NoSignedWrap is set. Value *InstCombiner::Descale(Value *Val, APInt Scale, bool &NoSignedWrap) { assert(isa<IntegerType>(Val->getType()) && "Can only descale integers!"); assert(cast<IntegerType>(Val->getType())->getBitWidth() == @@ -1008,11 +1040,11 @@ Value *InstCombiner::Descale(Value *Val, APInt Scale, bool &NoSignedWrap) { // 0'th operand of Val. std::pair<Instruction*, unsigned> Parent; - // RequireNoSignedWrap - Set if the transform requires a descaling at deeper - // levels that doesn't overflow. + // Set if the transform requires a descaling at deeper levels that doesn't + // overflow. bool RequireNoSignedWrap = false; - // logScale - log base 2 of the scale. Negative if not a power of 2. + // Log base 2 of the scale. Negative if not a power of 2. int32_t logScale = Scale.exactLogBase2(); for (;; Op = Parent.first->getOperand(Parent.second)) { // Drill down @@ -1213,16 +1245,11 @@ Value *InstCombiner::Descale(Value *Val, APInt Scale, bool &NoSignedWrap) { /// specified one but with other operands. static Value *CreateBinOpAsGiven(BinaryOperator &Inst, Value *LHS, Value *RHS, InstCombiner::BuilderTy *B) { - Value *BORes = B->CreateBinOp(Inst.getOpcode(), LHS, RHS); - if (BinaryOperator *NewBO = dyn_cast<BinaryOperator>(BORes)) { - if (isa<OverflowingBinaryOperator>(NewBO)) { - NewBO->setHasNoSignedWrap(Inst.hasNoSignedWrap()); - NewBO->setHasNoUnsignedWrap(Inst.hasNoUnsignedWrap()); - } - if (isa<PossiblyExactOperator>(NewBO)) - NewBO->setIsExact(Inst.isExact()); - } - return BORes; + Value *BO = B->CreateBinOp(Inst.getOpcode(), LHS, RHS); + // If LHS and RHS are constant, BO won't be a binary operator. + if (BinaryOperator *NewBO = dyn_cast<BinaryOperator>(BO)) + NewBO->copyIRFlags(&Inst); + return BO; } /// \brief Makes transformation of binary operation specific for vector types. @@ -1256,9 +1283,8 @@ Value *InstCombiner::SimplifyVectorOp(BinaryOperator &Inst) { LShuf->getMask() == RShuf->getMask()) { Value *NewBO = CreateBinOpAsGiven(Inst, LShuf->getOperand(0), RShuf->getOperand(0), Builder); - Value *Res = Builder->CreateShuffleVector(NewBO, + return Builder->CreateShuffleVector(NewBO, UndefValue::get(NewBO->getType()), LShuf->getMask()); - return Res; } } @@ -1294,18 +1320,11 @@ Value *InstCombiner::SimplifyVectorOp(BinaryOperator &Inst) { } if (MayChange) { Constant *C2 = ConstantVector::get(C2M); - Value *NewLHS, *NewRHS; - if (isa<Constant>(LHS)) { - NewLHS = C2; - NewRHS = Shuffle->getOperand(0); - } else { - NewLHS = Shuffle->getOperand(0); - NewRHS = C2; - } + Value *NewLHS = isa<Constant>(LHS) ? C2 : Shuffle->getOperand(0); + Value *NewRHS = isa<Constant>(LHS) ? Shuffle->getOperand(0) : C2; Value *NewBO = CreateBinOpAsGiven(Inst, NewLHS, NewRHS, Builder); - Value *Res = Builder->CreateShuffleVector(NewBO, + return Builder->CreateShuffleVector(NewBO, UndefValue::get(Inst.getType()), Shuffle->getMask()); - return Res; } } @@ -1323,7 +1342,8 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { // Eliminate unneeded casts for indices, and replace indices which displace // by multiples of a zero size type with zero. bool MadeChange = false; - Type *IntPtrTy = DL.getIntPtrType(GEP.getPointerOperandType()); + Type *IntPtrTy = + DL.getIntPtrType(GEP.getPointerOperandType()->getScalarType()); gep_type_iterator GTI = gep_type_begin(GEP); for (User::op_iterator I = GEP.op_begin() + 1, E = GEP.op_end(); I != E; @@ -1333,21 +1353,25 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { if (!SeqTy) continue; + // Index type should have the same width as IntPtr + Type *IndexTy = (*I)->getType(); + Type *NewIndexType = IndexTy->isVectorTy() ? + VectorType::get(IntPtrTy, IndexTy->getVectorNumElements()) : IntPtrTy; + // If the element type has zero size then any index over it is equivalent // to an index of zero, so replace it with zero if it is not zero already. if (SeqTy->getElementType()->isSized() && DL.getTypeAllocSize(SeqTy->getElementType()) == 0) if (!isa<Constant>(*I) || !cast<Constant>(*I)->isNullValue()) { - *I = Constant::getNullValue(IntPtrTy); + *I = Constant::getNullValue(NewIndexType); MadeChange = true; } - Type *IndexTy = (*I)->getType(); - if (IndexTy != IntPtrTy) { + if (IndexTy != NewIndexType) { // If we are using a wider index than needed for this platform, shrink // it to what we need. If narrower, sign-extend it to what we need. // This explicit cast can make subsequent optimizations more obvious. - *I = Builder->CreateIntCast(*I, IntPtrTy, true); + *I = Builder->CreateIntCast(*I, NewIndexType, true); MadeChange = true; } } @@ -1421,8 +1445,13 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { } } - GetElementPtrInst *NewGEP = cast<GetElementPtrInst>(Op1->clone()); + // If not all GEPs are identical we'll have to create a new PHI node. + // Check that the old PHI node has only one use so that it will get + // removed. + if (DI != -1 && !PN->hasOneUse()) + return nullptr; + GetElementPtrInst *NewGEP = cast<GetElementPtrInst>(Op1->clone()); if (DI == -1) { // All the GEPs feeding the PHI are identical. Clone one down into our // BB so that it can be merged with the current GEP. @@ -1432,11 +1461,13 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { // All the GEPs feeding the PHI differ at a single offset. Clone a GEP // into the current block so it can be merged, and create a new PHI to // set that index. - Instruction *InsertPt = Builder->GetInsertPoint(); - Builder->SetInsertPoint(PN); - PHINode *NewPN = Builder->CreatePHI(Op1->getOperand(DI)->getType(), - PN->getNumOperands()); - Builder->SetInsertPoint(InsertPt); + PHINode *NewPN; + { + IRBuilderBase::InsertPointGuard Guard(*Builder); + Builder->SetInsertPoint(PN); + NewPN = Builder->CreatePHI(Op1->getOperand(DI)->getType(), + PN->getNumOperands()); + } for (auto &I : PN->operands()) NewPN->addIncoming(cast<GEPOperator>(I)->getOperand(DI), @@ -1790,7 +1821,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { if (Instruction *I = visitBitCast(*BCI)) { if (I != BCI) { I->takeName(BCI); - BCI->getParent()->getInstList().insert(BCI, I); + BCI->getParent()->getInstList().insert(BCI->getIterator(), I); ReplaceInstUsesWith(*BCI, I); } return &GEP; @@ -1931,7 +1962,7 @@ Instruction *InstCombiner::visitAllocSite(Instruction &MI) { if (InvokeInst *II = dyn_cast<InvokeInst>(&MI)) { // Replace invoke with a NOP intrinsic to maintain the original CFG - Module *M = II->getParent()->getParent()->getParent(); + Module *M = II->getModule(); Function *F = Intrinsic::getDeclaration(M, Intrinsic::donothing); InvokeInst::Create(F, II->getNormalDest(), II->getUnwindDest(), None, "", II->getParent()); @@ -2280,9 +2311,10 @@ Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) { } if (LoadInst *L = dyn_cast<LoadInst>(Agg)) // If the (non-volatile) load only has one use, we can rewrite this to a - // load from a GEP. This reduces the size of the load. - // FIXME: If a load is used only by extractvalue instructions then this - // could be done regardless of having multiple uses. + // load from a GEP. This reduces the size of the load. If a load is used + // only by extractvalue instructions then this either must have been + // optimized before, or it is a struct with padding, in which case we + // don't want to do the transformation as it loses padding knowledge. if (L->isSimple() && L->hasOneUse()) { // extractvalue has integer indices, getelementptr has Value*s. Convert. SmallVector<Value*, 4> Indices; @@ -2294,7 +2326,7 @@ Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) { // We need to insert these at the location of the old load, not at that of // the extractvalue. - Builder->SetInsertPoint(L->getParent(), L); + Builder->SetInsertPoint(L); Value *GEP = Builder->CreateInBoundsGEP(L->getType(), L->getPointerOperand(), Indices); // Returning the load directly will cause the main loop to insert it in @@ -2312,7 +2344,7 @@ Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) { return nullptr; } -/// isCatchAll - Return 'true' if the given typeinfo will match anything. +/// Return 'true' if the given typeinfo will match anything. static bool isCatchAll(EHPersonality Personality, Constant *TypeInfo) { switch (Personality) { case EHPersonality::GNU_C: @@ -2330,6 +2362,7 @@ static bool isCatchAll(EHPersonality Personality, Constant *TypeInfo) { case EHPersonality::MSVC_X86SEH: case EHPersonality::MSVC_Win64SEH: case EHPersonality::MSVC_CXX: + case EHPersonality::CoreCLR: return TypeInfo->isNullValue(); } llvm_unreachable("invalid enum"); @@ -2441,10 +2474,24 @@ Instruction *InstCombiner::visitLandingPadInst(LandingPadInst &LI) { SawCatchAll = true; break; } - if (AlreadyCaught.count(TypeInfo)) - // Already caught by an earlier clause, so having it in the filter - // is pointless. - continue; + + // Even if we've seen a type in a catch clause, we don't want to + // remove it from the filter. An unexpected type handler may be + // set up for a call site which throws an exception of the same + // type caught. In order for the exception thrown by the unexpected + // handler to propogate correctly, the filter must be correctly + // described for the call site. + // + // Example: + // + // void unexpected() { throw 1;} + // void foo() throw (int) { + // std::set_unexpected(unexpected); + // try { + // throw 2.0; + // } catch (int i) {} + // } + // There is no point in having multiple copies of the same typeinfo in // a filter, so only add it if we didn't already. if (SeenInFilter.insert(TypeInfo).second) @@ -2637,15 +2684,15 @@ Instruction *InstCombiner::visitLandingPadInst(LandingPadInst &LI) { return nullptr; } -/// TryToSinkInstruction - Try to move the specified instruction from its -/// current block into the beginning of DestBlock, which can only happen if it's -/// safe to move the instruction past all of the instructions between it and the -/// end of its block. +/// Try to move the specified instruction from its current block into the +/// beginning of DestBlock, which can only happen if it's safe to move the +/// instruction past all of the instructions between it and the end of its +/// block. static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock) { assert(I->hasOneUse() && "Invariants didn't hold!"); // Cannot move control-flow-involving, volatile loads, vaarg, etc. - if (isa<PHINode>(I) || isa<LandingPadInst>(I) || I->mayHaveSideEffects() || + if (isa<PHINode>(I) || I->isEHPad() || I->mayHaveSideEffects() || isa<TerminatorInst>(I)) return false; @@ -2654,17 +2701,24 @@ static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock) { &DestBlock->getParent()->getEntryBlock()) return false; + // Do not sink convergent call instructions. + if (auto *CI = dyn_cast<CallInst>(I)) { + if (CI->isConvergent()) + return false; + } + // We can only sink load instructions if there is nothing between the load and // the end of block that could change the value. if (I->mayReadFromMemory()) { - for (BasicBlock::iterator Scan = I, E = I->getParent()->end(); + for (BasicBlock::iterator Scan = I->getIterator(), + E = I->getParent()->end(); Scan != E; ++Scan) if (Scan->mayWriteToMemory()) return false; } BasicBlock::iterator InsertPos = DestBlock->getFirstInsertionPt(); - I->moveBefore(InsertPos); + I->moveBefore(&*InsertPos); ++NumSunkInst; return true; } @@ -2698,6 +2752,27 @@ bool InstCombiner::run() { } } + // In general, it is possible for computeKnownBits to determine all bits in a + // value even when the operands are not all constants. + if (!I->use_empty() && I->getType()->isIntegerTy()) { + unsigned BitWidth = I->getType()->getScalarSizeInBits(); + APInt KnownZero(BitWidth, 0); + APInt KnownOne(BitWidth, 0); + computeKnownBits(I, KnownZero, KnownOne, /*Depth*/0, I); + if ((KnownZero | KnownOne).isAllOnesValue()) { + Constant *C = ConstantInt::get(I->getContext(), KnownOne); + DEBUG(dbgs() << "IC: ConstFold (all bits known) to: " << *C << + " from: " << *I << '\n'); + + // Add operands to the worklist. + ReplaceInstUsesWith(*I, C); + ++NumConstProp; + EraseInstFromFunction(*I); + MadeIRChange = true; + continue; + } + } + // See if we can trivially sink this instruction to a successor basic block. if (I->hasOneUse()) { BasicBlock *BB = I->getParent(); @@ -2738,7 +2813,7 @@ bool InstCombiner::run() { } // Now that we have an instruction, try combining it to simplify it. - Builder->SetInsertPoint(I->getParent(), I); + Builder->SetInsertPoint(I); Builder->SetCurrentDebugLocation(I->getDebugLoc()); #ifndef NDEBUG @@ -2768,7 +2843,7 @@ bool InstCombiner::run() { // Insert the new instruction into the basic block... BasicBlock *InstParent = I->getParent(); - BasicBlock::iterator InsertPos = I; + BasicBlock::iterator InsertPos = I->getIterator(); // If we replace a PHI with something that isn't a PHI, fix up the // insertion point. @@ -2801,8 +2876,8 @@ bool InstCombiner::run() { return MadeIRChange; } -/// AddReachableCodeToWorklist - Walk the function in depth-first order, adding -/// all reachable code to the worklist. +/// Walk the function in depth-first order, adding all reachable code to the +/// worklist. /// /// This has a couple of tricks to make the code faster and more powerful. In /// particular, we constant fold and DCE instructions as we go, to avoid adding @@ -2829,7 +2904,7 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL, continue; for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) { - Instruction *Inst = BBI++; + Instruction *Inst = &*BBI++; // DCE instruction if trivially dead. if (isInstructionTriviallyDead(Inst, TLI)) { @@ -2900,8 +2975,8 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL, } } - for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) - Worklist.push_back(TI->getSuccessor(i)); + for (BasicBlock *SuccBB : TI->successors()) + Worklist.push_back(SuccBB); } while (!Worklist.empty()); // Once we've found all of the instructions to add to instcombine's worklist, @@ -2909,8 +2984,7 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL, // of the function down. This jives well with the way that it adds all uses // of instructions to the worklist after doing a transformation, thus avoiding // some N^2 behavior in pathological cases. - ICWorklist.AddInitialGroup(&InstrsForInstCombineWorklist[0], - InstrsForInstCombineWorklist.size()); + ICWorklist.AddInitialGroup(InstrsForInstCombineWorklist); return MadeIRChange; } @@ -2930,13 +3004,13 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL, // track of which blocks we visit. SmallPtrSet<BasicBlock *, 64> Visited; MadeIRChange |= - AddReachableCodeToWorklist(F.begin(), DL, Visited, ICWorklist, TLI); + AddReachableCodeToWorklist(&F.front(), DL, Visited, ICWorklist, TLI); // Do a quick scan over the function. If we find any blocks that are // unreachable, remove any instructions inside of them. This prevents // the instcombine code from having to deal with some bad special cases. for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) { - if (Visited.count(BB)) + if (Visited.count(&*BB)) continue; // Delete the instructions backwards, as it has a reduced likelihood of @@ -2944,11 +3018,10 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL, Instruction *EndInst = BB->getTerminator(); // Last not to be deleted. while (EndInst != BB->begin()) { // Delete the next to last instruction. - BasicBlock::iterator I = EndInst; - Instruction *Inst = --I; - if (!Inst->use_empty()) + Instruction *Inst = &*--EndInst->getIterator(); + if (!Inst->use_empty() && !Inst->getType()->isTokenTy()) Inst->replaceAllUsesWith(UndefValue::get(Inst->getType())); - if (isa<LandingPadInst>(Inst)) { + if (Inst->isEHPad()) { EndInst = Inst; continue; } @@ -2956,7 +3029,8 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL, ++NumDeadInst; MadeIRChange = true; } - Inst->eraseFromParent(); + if (!Inst->getType()->isTokenTy()) + Inst->eraseFromParent(); } } @@ -2968,8 +3042,6 @@ combineInstructionsOverFunction(Function &F, InstCombineWorklist &Worklist, AliasAnalysis *AA, AssumptionCache &AC, TargetLibraryInfo &TLI, DominatorTree &DT, LoopInfo *LI = nullptr) { - // Minimizing size? - bool MinimizeSize = F.hasFnAttribute(Attribute::MinSize); auto &DL = F.getParent()->getDataLayout(); /// Builder - This is an IRBuilder that automatically inserts new @@ -2992,7 +3064,7 @@ combineInstructionsOverFunction(Function &F, InstCombineWorklist &Worklist, if (prepareICWorklistFromFunction(F, DL, &TLI, Worklist)) Changed = true; - InstCombiner IC(Worklist, &Builder, MinimizeSize, + InstCombiner IC(Worklist, &Builder, F.optForMinSize(), AA, &AC, &TLI, &DT, DL, LI); if (IC.run()) Changed = true; @@ -3046,11 +3118,12 @@ public: void InstructionCombiningPass::getAnalysisUsage(AnalysisUsage &AU) const { AU.setPreservesCFG(); - AU.addRequired<AliasAnalysis>(); + AU.addRequired<AAResultsWrapperPass>(); AU.addRequired<AssumptionCacheTracker>(); AU.addRequired<TargetLibraryInfoWrapperPass>(); AU.addRequired<DominatorTreeWrapperPass>(); AU.addPreserved<DominatorTreeWrapperPass>(); + AU.addPreserved<GlobalsAAWrapperPass>(); } bool InstructionCombiningPass::runOnFunction(Function &F) { @@ -3058,7 +3131,7 @@ bool InstructionCombiningPass::runOnFunction(Function &F) { return false; // Required analyses. - auto AA = &getAnalysis<AliasAnalysis>(); + auto AA = &getAnalysis<AAResultsWrapperPass>().getAAResults(); auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F); auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(); auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree(); @@ -3076,7 +3149,8 @@ INITIALIZE_PASS_BEGIN(InstructionCombiningPass, "instcombine", INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker) INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass) INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) -INITIALIZE_AG_DEPENDENCY(AliasAnalysis) +INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass) +INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass) INITIALIZE_PASS_END(InstructionCombiningPass, "instcombine", "Combine redundant instructions", false, false) |