diff options
Diffstat (limited to 'contrib/llvm/lib/Transforms/Scalar')
14 files changed, 564 insertions, 414 deletions
diff --git a/contrib/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/contrib/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp index d1302c6..79624b2 100644 --- a/contrib/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp @@ -113,10 +113,11 @@ bool CorrelatedValuePropagation::processPHI(PHINode *P) { Value *Condition = SI->getCondition(); if (!Condition->getType()->isVectorTy()) { - if (Constant *C = LVI->getConstantOnEdge(Condition, P->getIncomingBlock(i), BB, P)) { - if (C == ConstantInt::getTrue(Condition->getType())) { + if (Constant *C = LVI->getConstantOnEdge( + Condition, P->getIncomingBlock(i), BB, P)) { + if (C->isOneValue()) { V = SI->getTrueValue(); - } else { + } else if (C->isZeroValue()) { V = SI->getFalseValue(); } // Once LVI learns to handle vector types, we could also add support diff --git a/contrib/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/contrib/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp index 01952cf..eb48a76 100644 --- a/contrib/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp @@ -197,11 +197,11 @@ static bool hasMemoryWrite(Instruction *I, const TargetLibraryInfo *TLI) { static AliasAnalysis::Location getLocForWrite(Instruction *Inst, AliasAnalysis &AA) { if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) - return AA.getLocation(SI); + return MemoryLocation::get(SI); if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(Inst)) { // memcpy/memmove/memset. - AliasAnalysis::Location Loc = AA.getLocationForDest(MI); + AliasAnalysis::Location Loc = MemoryLocation::getForDest(MI); return Loc; } @@ -231,7 +231,7 @@ getLocForRead(Instruction *Inst, AliasAnalysis &AA) { // The only instructions that both read and write are the mem transfer // instructions (memcpy/memmove). if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(Inst)) - return AA.getLocationForSource(MTI); + return MemoryLocation::getForSource(MTI); return AliasAnalysis::Location(); } @@ -815,11 +815,11 @@ bool DSE::handleEndBlock(BasicBlock &BB) { if (LoadInst *L = dyn_cast<LoadInst>(BBI)) { if (!L->isUnordered()) // Be conservative with atomic/volatile load break; - LoadedLoc = AA->getLocation(L); + LoadedLoc = MemoryLocation::get(L); } else if (VAArgInst *V = dyn_cast<VAArgInst>(BBI)) { - LoadedLoc = AA->getLocation(V); + LoadedLoc = MemoryLocation::get(V); } else if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(BBI)) { - LoadedLoc = AA->getLocationForSource(MTI); + LoadedLoc = MemoryLocation::getForSource(MTI); } else if (!BBI->mayReadFromMemory()) { // Instruction doesn't read memory. Note that stores that weren't removed // above will hit this case. diff --git a/contrib/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/contrib/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp index 600589c..359a616 100644 --- a/contrib/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -68,6 +68,22 @@ static cl::opt<bool> VerifyIndvars( static cl::opt<bool> ReduceLiveIVs("liv-reduce", cl::Hidden, cl::desc("Reduce live induction variables.")); +enum ReplaceExitVal { NeverRepl, OnlyCheapRepl, AlwaysRepl }; + +static cl::opt<ReplaceExitVal> ReplaceExitValue( + "replexitval", cl::Hidden, cl::init(OnlyCheapRepl), + cl::desc("Choose the strategy to replace exit value in IndVarSimplify"), + cl::values(clEnumValN(NeverRepl, "never", "never replace exit value"), + clEnumValN(OnlyCheapRepl, "cheap", + "only replace exit value when the cost is cheap"), + clEnumValN(AlwaysRepl, "always", + "always replace exit value whenever possible"), + clEnumValEnd)); + +namespace { +struct RewritePhi; +} + namespace { class IndVarSimplify : public LoopPass { LoopInfo *LI; @@ -112,6 +128,7 @@ namespace { void SimplifyAndExtend(Loop *L, SCEVExpander &Rewriter, LPPassManager &LPM); + bool CanLoopBeDeleted(Loop *L, SmallVector<RewritePhi, 8> &RewritePhiSet); void RewriteLoopExitValues(Loop *L, SCEVExpander &Rewriter); Value *LinearFunctionTestReplace(Loop *L, const SCEV *BackedgeTakenCount, @@ -464,6 +481,21 @@ void IndVarSimplify::RewriteNonIntegerIVs(Loop *L) { SE->forgetLoop(L); } +namespace { +// Collect information about PHI nodes which can be transformed in +// RewriteLoopExitValues. +struct RewritePhi { + PHINode *PN; + unsigned Ith; // Ith incoming value. + Value *Val; // Exit value after expansion. + bool HighCost; // High Cost when expansion. + bool SafePhi; // LCSSASafePhiForRAUW. + + RewritePhi(PHINode *P, unsigned I, Value *V, bool H, bool S) + : PN(P), Ith(I), Val(V), HighCost(H), SafePhi(S) {} +}; +} + //===----------------------------------------------------------------------===// // RewriteLoopExitValues - Optimize IV users outside the loop. // As a side effect, reduces the amount of IV processing within the loop. @@ -486,6 +518,7 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, SCEVExpander &Rewriter) { SmallVector<BasicBlock*, 8> ExitBlocks; L->getUniqueExitBlocks(ExitBlocks); + SmallVector<RewritePhi, 8> RewritePhiSet; // Find all values that are computed inside the loop, but used outside of it. // Because of LCSSA, these values will only occur in LCSSA PHI Nodes. Scan // the exit blocks of the loop to find them. @@ -604,23 +637,44 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, SCEVExpander &Rewriter) { DeadInsts.push_back(ExitVal); continue; } - Changed = true; - ++NumReplaced; + bool HighCost = Rewriter.isHighCostExpansion(ExitValue, L); - PN->setIncomingValue(i, ExitVal); + // Collect all the candidate PHINodes to be rewritten. + RewritePhiSet.push_back( + RewritePhi(PN, i, ExitVal, HighCost, LCSSASafePhiForRAUW)); + } + } + } - // If this instruction is dead now, delete it. Don't do it now to avoid - // invalidating iterators. - if (isInstructionTriviallyDead(Inst, TLI)) - DeadInsts.push_back(Inst); + bool LoopCanBeDel = CanLoopBeDeleted(L, RewritePhiSet); - // If we determined that this PHI is safe to replace even if an LCSSA - // PHI, do so. - if (LCSSASafePhiForRAUW) { - PN->replaceAllUsesWith(ExitVal); - PN->eraseFromParent(); - } - } + // Transformation. + for (const RewritePhi &Phi : RewritePhiSet) { + PHINode *PN = Phi.PN; + Value *ExitVal = Phi.Val; + + // Only do the rewrite when the ExitValue can be expanded cheaply. + // If LoopCanBeDel is true, rewrite exit value aggressively. + if (ReplaceExitValue == OnlyCheapRepl && !LoopCanBeDel && Phi.HighCost) { + DeadInsts.push_back(ExitVal); + continue; + } + + Changed = true; + ++NumReplaced; + Instruction *Inst = cast<Instruction>(PN->getIncomingValue(Phi.Ith)); + PN->setIncomingValue(Phi.Ith, ExitVal); + + // If this instruction is dead now, delete it. Don't do it now to avoid + // invalidating iterators. + if (isInstructionTriviallyDead(Inst, TLI)) + DeadInsts.push_back(Inst); + + // If we determined that this PHI is safe to replace even if an LCSSA + // PHI, do so. + if (Phi.SafePhi) { + PN->replaceAllUsesWith(ExitVal); + PN->eraseFromParent(); } } @@ -629,6 +683,65 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, SCEVExpander &Rewriter) { Rewriter.clearInsertPoint(); } +/// CanLoopBeDeleted - Check whether it is possible to delete the loop after +/// rewriting exit value. If it is possible, ignore ReplaceExitValue and +/// do rewriting aggressively. +bool IndVarSimplify::CanLoopBeDeleted( + Loop *L, SmallVector<RewritePhi, 8> &RewritePhiSet) { + + BasicBlock *Preheader = L->getLoopPreheader(); + // If there is no preheader, the loop will not be deleted. + if (!Preheader) + return false; + + // In LoopDeletion pass Loop can be deleted when ExitingBlocks.size() > 1. + // We obviate multiple ExitingBlocks case for simplicity. + // TODO: If we see testcase with multiple ExitingBlocks can be deleted + // after exit value rewriting, we can enhance the logic here. + SmallVector<BasicBlock *, 4> ExitingBlocks; + L->getExitingBlocks(ExitingBlocks); + SmallVector<BasicBlock *, 8> ExitBlocks; + L->getUniqueExitBlocks(ExitBlocks); + if (ExitBlocks.size() > 1 || ExitingBlocks.size() > 1) + return false; + + BasicBlock *ExitBlock = ExitBlocks[0]; + BasicBlock::iterator BI = ExitBlock->begin(); + while (PHINode *P = dyn_cast<PHINode>(BI)) { + Value *Incoming = P->getIncomingValueForBlock(ExitingBlocks[0]); + + // If the Incoming value of P is found in RewritePhiSet, we know it + // could be rewritten to use a loop invariant value in transformation + // phase later. Skip it in the loop invariant check below. + bool found = false; + for (const RewritePhi &Phi : RewritePhiSet) { + unsigned i = Phi.Ith; + if (Phi.PN == P && (Phi.PN)->getIncomingValue(i) == Incoming) { + found = true; + break; + } + } + + Instruction *I; + if (!found && (I = dyn_cast<Instruction>(Incoming))) + if (!L->hasLoopInvariantOperands(I)) + return false; + + ++BI; + } + + for (Loop::block_iterator LI = L->block_begin(), LE = L->block_end(); + LI != LE; ++LI) { + for (BasicBlock::iterator BI = (*LI)->begin(), BE = (*LI)->end(); BI != BE; + ++BI) { + if (BI->mayHaveSideEffects()) + return false; + } + } + + return true; +} + //===----------------------------------------------------------------------===// // IV Widening - Extend the width of an IV to cover its widest uses. //===----------------------------------------------------------------------===// @@ -989,7 +1102,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) { IRBuilder<> Builder(WidePhi->getParent()->getFirstInsertionPt()); Value *Trunc = Builder.CreateTrunc(WidePhi, DU.NarrowDef->getType()); UsePhi->replaceAllUsesWith(Trunc); - DeadInsts.push_back(UsePhi); + DeadInsts.emplace_back(UsePhi); DEBUG(dbgs() << "INDVARS: Widen lcssa phi " << *UsePhi << " to " << *WidePhi << "\n"); } @@ -1022,7 +1135,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) { << " replaced by " << *DU.WideDef << "\n"); ++NumElimExt; DU.NarrowUse->replaceAllUsesWith(NewDef); - DeadInsts.push_back(DU.NarrowUse); + DeadInsts.emplace_back(DU.NarrowUse); } // Now that the extend is gone, we want to expose it's uses for potential // further simplification. We don't need to directly inform SimplifyIVUsers @@ -1075,7 +1188,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) { if (WideAddRec != SE->getSCEV(WideUse)) { DEBUG(dbgs() << "Wide use expression mismatch: " << *WideUse << ": " << *SE->getSCEV(WideUse) << " != " << *WideAddRec << "\n"); - DeadInsts.push_back(WideUse); + DeadInsts.emplace_back(WideUse); return nullptr; } @@ -1172,7 +1285,7 @@ PHINode *WidenIV::CreateWideIV(SCEVExpander &Rewriter) { // WidenIVUse may have removed the def-use edge. if (DU.NarrowDef->use_empty()) - DeadInsts.push_back(DU.NarrowDef); + DeadInsts.emplace_back(DU.NarrowDef); } return WidePhi; } @@ -1867,7 +1980,8 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) { // loop into any instructions outside of the loop that use the final values of // the current expressions. // - if (!isa<SCEVCouldNotCompute>(BackedgeTakenCount)) + if (ReplaceExitValue != NeverRepl && + !isa<SCEVCouldNotCompute>(BackedgeTakenCount)) RewriteLoopExitValues(L, Rewriter); // Eliminate redundant IV cycles. diff --git a/contrib/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/contrib/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 584c7ae..4b59f3d 100644 --- a/contrib/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -811,7 +811,7 @@ DeleteTriviallyDeadInstructions(SmallVectorImpl<WeakVH> &DeadInsts) { if (Instruction *U = dyn_cast<Instruction>(O)) { O = nullptr; if (U->use_empty()) - DeadInsts.push_back(U); + DeadInsts.emplace_back(U); } I->eraseFromParent(); @@ -2917,7 +2917,7 @@ void LSRInstance::GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter, IVOper = Builder.CreateTruncOrBitCast(IVOper, OperTy, "lsr.chain"); } Inc.UserInst->replaceUsesOfWith(Inc.IVOperand, IVOper); - DeadInsts.push_back(Inc.IVOperand); + DeadInsts.emplace_back(Inc.IVOperand); } // If LSR created a new, wider phi, we may also replace its postinc. We only // do this if we also found a wide value for the head of the chain. @@ -2939,7 +2939,7 @@ void LSRInstance::GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter, IVOper = Builder.CreatePointerCast(IVSrc, PostIncTy, "lsr.chain"); } Phi->replaceUsesOfWith(PostIncV, IVOper); - DeadInsts.push_back(PostIncV); + DeadInsts.emplace_back(PostIncV); } } } @@ -4594,7 +4594,7 @@ Value *LSRInstance::Expand(const LSRFixup &LF, // form, update the ICmp's other operand. if (LU.Kind == LSRUse::ICmpZero) { ICmpInst *CI = cast<ICmpInst>(LF.UserInst); - DeadInsts.push_back(CI->getOperand(1)); + DeadInsts.emplace_back(CI->getOperand(1)); assert(!F.BaseGV && "ICmp does not support folding a global value and " "a scale at the same time!"); if (F.Scale == -1) { @@ -4737,7 +4737,7 @@ void LSRInstance::Rewrite(const LSRFixup &LF, LF.UserInst->replaceUsesOfWith(LF.OperandValToReplace, FullV); } - DeadInsts.push_back(LF.OperandValToReplace); + DeadInsts.emplace_back(LF.OperandValToReplace); } /// ImplementSolution - Rewrite all the fixup locations with new values, diff --git a/contrib/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/contrib/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp index ccafd10..4ccbfc9 100644 --- a/contrib/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp @@ -38,25 +38,25 @@ using namespace llvm; #define DEBUG_TYPE "loop-unroll" static cl::opt<unsigned> -UnrollThreshold("unroll-threshold", cl::init(150), cl::Hidden, - cl::desc("The cut-off point for automatic loop unrolling")); + UnrollThreshold("unroll-threshold", cl::init(150), cl::Hidden, + cl::desc("The baseline cost threshold for loop unrolling")); + +static cl::opt<unsigned> UnrollPercentDynamicCostSavedThreshold( + "unroll-percent-dynamic-cost-saved-threshold", cl::init(20), cl::Hidden, + cl::desc("The percentage of estimated dynamic cost which must be saved by " + "unrolling to allow unrolling up to the max threshold.")); + +static cl::opt<unsigned> UnrollDynamicCostSavingsDiscount( + "unroll-dynamic-cost-savings-discount", cl::init(2000), cl::Hidden, + cl::desc("This is the amount discounted from the total unroll cost when " + "the unrolled form has a high dynamic cost savings (triggered by " + "the '-unroll-perecent-dynamic-cost-saved-threshold' flag).")); static cl::opt<unsigned> UnrollMaxIterationsCountToAnalyze( "unroll-max-iteration-count-to-analyze", cl::init(0), cl::Hidden, cl::desc("Don't allow loop unrolling to simulate more than this number of" "iterations when checking full unroll profitability")); -static cl::opt<unsigned> UnrollMinPercentOfOptimized( - "unroll-percent-of-optimized-for-complete-unroll", cl::init(20), cl::Hidden, - cl::desc("If complete unrolling could trigger further optimizations, and, " - "by that, remove the given percent of instructions, perform the " - "complete unroll even if it's beyond the threshold")); - -static cl::opt<unsigned> UnrollAbsoluteThreshold( - "unroll-absolute-threshold", cl::init(2000), cl::Hidden, - cl::desc("Don't unroll if the unrolled size is bigger than this threshold," - " even if we can remove big portion of instructions later.")); - static cl::opt<unsigned> UnrollCount("unroll-count", cl::init(0), cl::Hidden, cl::desc("Use this unroll count for all loops including those with " @@ -82,16 +82,18 @@ namespace { static char ID; // Pass ID, replacement for typeid LoopUnroll(int T = -1, int C = -1, int P = -1, int R = -1) : LoopPass(ID) { CurrentThreshold = (T == -1) ? UnrollThreshold : unsigned(T); - CurrentAbsoluteThreshold = UnrollAbsoluteThreshold; - CurrentMinPercentOfOptimized = UnrollMinPercentOfOptimized; + CurrentPercentDynamicCostSavedThreshold = + UnrollPercentDynamicCostSavedThreshold; + CurrentDynamicCostSavingsDiscount = UnrollDynamicCostSavingsDiscount; CurrentCount = (C == -1) ? UnrollCount : unsigned(C); CurrentAllowPartial = (P == -1) ? UnrollAllowPartial : (bool)P; CurrentRuntime = (R == -1) ? UnrollRuntime : (bool)R; UserThreshold = (T != -1) || (UnrollThreshold.getNumOccurrences() > 0); - UserAbsoluteThreshold = (UnrollAbsoluteThreshold.getNumOccurrences() > 0); - UserPercentOfOptimized = - (UnrollMinPercentOfOptimized.getNumOccurrences() > 0); + UserPercentDynamicCostSavedThreshold = + (UnrollPercentDynamicCostSavedThreshold.getNumOccurrences() > 0); + UserDynamicCostSavingsDiscount = + (UnrollDynamicCostSavingsDiscount.getNumOccurrences() > 0); UserAllowPartial = (P != -1) || (UnrollAllowPartial.getNumOccurrences() > 0); UserRuntime = (R != -1) || (UnrollRuntime.getNumOccurrences() > 0); @@ -115,18 +117,18 @@ namespace { unsigned CurrentCount; unsigned CurrentThreshold; - unsigned CurrentAbsoluteThreshold; - unsigned CurrentMinPercentOfOptimized; - bool CurrentAllowPartial; - bool CurrentRuntime; - bool UserCount; // CurrentCount is user-specified. - bool UserThreshold; // CurrentThreshold is user-specified. - bool UserAbsoluteThreshold; // CurrentAbsoluteThreshold is - // user-specified. - bool UserPercentOfOptimized; // CurrentMinPercentOfOptimized is - // user-specified. - bool UserAllowPartial; // CurrentAllowPartial is user-specified. - bool UserRuntime; // CurrentRuntime is user-specified. + unsigned CurrentPercentDynamicCostSavedThreshold; + unsigned CurrentDynamicCostSavingsDiscount; + bool CurrentAllowPartial; + bool CurrentRuntime; + + // Flags for whether the 'current' settings are user-specified. + bool UserCount; + bool UserThreshold; + bool UserPercentDynamicCostSavedThreshold; + bool UserDynamicCostSavingsDiscount; + bool UserAllowPartial; + bool UserRuntime; bool runOnLoop(Loop *L, LPPassManager &LPM) override; @@ -156,8 +158,9 @@ namespace { void getUnrollingPreferences(Loop *L, const TargetTransformInfo &TTI, TargetTransformInfo::UnrollingPreferences &UP) { UP.Threshold = CurrentThreshold; - UP.AbsoluteThreshold = CurrentAbsoluteThreshold; - UP.MinPercentOfOptimized = CurrentMinPercentOfOptimized; + UP.PercentDynamicCostSavedThreshold = + CurrentPercentDynamicCostSavedThreshold; + UP.DynamicCostSavingsDiscount = CurrentDynamicCostSavingsDiscount; UP.OptSizeThreshold = OptSizeUnrollThreshold; UP.PartialThreshold = CurrentThreshold; UP.PartialOptSizeThreshold = OptSizeUnrollThreshold; @@ -186,8 +189,8 @@ namespace { void selectThresholds(const Loop *L, bool HasPragma, const TargetTransformInfo::UnrollingPreferences &UP, unsigned &Threshold, unsigned &PartialThreshold, - unsigned &AbsoluteThreshold, - unsigned &PercentOfOptimizedForCompleteUnroll) { + unsigned &PercentDynamicCostSavedThreshold, + unsigned &DynamicCostSavingsDiscount) { // Determine the current unrolling threshold. While this is // normally set from UnrollThreshold, it is overridden to a // smaller value if the current function is marked as @@ -195,11 +198,13 @@ namespace { // specified. Threshold = UserThreshold ? CurrentThreshold : UP.Threshold; PartialThreshold = UserThreshold ? CurrentThreshold : UP.PartialThreshold; - AbsoluteThreshold = UserAbsoluteThreshold ? CurrentAbsoluteThreshold - : UP.AbsoluteThreshold; - PercentOfOptimizedForCompleteUnroll = UserPercentOfOptimized - ? CurrentMinPercentOfOptimized - : UP.MinPercentOfOptimized; + PercentDynamicCostSavedThreshold = + UserPercentDynamicCostSavedThreshold + ? CurrentPercentDynamicCostSavedThreshold + : UP.PercentDynamicCostSavedThreshold; + DynamicCostSavingsDiscount = UserDynamicCostSavingsDiscount + ? CurrentDynamicCostSavingsDiscount + : UP.DynamicCostSavingsDiscount; if (!UserThreshold && L->getHeader()->getParent()->hasFnAttribute( @@ -220,9 +225,9 @@ namespace { } } bool canUnrollCompletely(Loop *L, unsigned Threshold, - unsigned AbsoluteThreshold, uint64_t UnrolledSize, - unsigned NumberOfOptimizedInstructions, - unsigned PercentOfOptimizedForCompleteUnroll); + unsigned PercentDynamicCostSavedThreshold, + unsigned DynamicCostSavingsDiscount, + uint64_t UnrolledCost, uint64_t RolledDynamicCost); }; } @@ -246,187 +251,6 @@ Pass *llvm::createSimpleLoopUnrollPass() { } namespace { -/// \brief SCEV expressions visitor used for finding expressions that would -/// become constants if the loop L is unrolled. -struct FindConstantPointers { - /// \brief Shows whether the expression is ConstAddress+Constant or not. - bool IndexIsConstant; - - /// \brief Used for filtering out SCEV expressions with two or more AddRec - /// subexpressions. - /// - /// Used to filter out complicated SCEV expressions, having several AddRec - /// sub-expressions. We don't handle them, because unrolling one loop - /// would help to replace only one of these inductions with a constant, and - /// consequently, the expression would remain non-constant. - bool HaveSeenAR; - - /// \brief If the SCEV expression becomes ConstAddress+Constant, this value - /// holds ConstAddress. Otherwise, it's nullptr. - Value *BaseAddress; - - /// \brief The loop, which we try to completely unroll. - const Loop *L; - - ScalarEvolution &SE; - - FindConstantPointers(const Loop *L, ScalarEvolution &SE) - : IndexIsConstant(true), HaveSeenAR(false), BaseAddress(nullptr), - L(L), SE(SE) {} - - /// Examine the given expression S and figure out, if it can be a part of an - /// expression, that could become a constant after the loop is unrolled. - /// The routine sets IndexIsConstant and HaveSeenAR according to the analysis - /// results. - /// \returns true if we need to examine subexpressions, and false otherwise. - bool follow(const SCEV *S) { - if (const SCEVUnknown *SC = dyn_cast<SCEVUnknown>(S)) { - // We've reached the leaf node of SCEV, it's most probably just a - // variable. - // If it's the only one SCEV-subexpression, then it might be a base - // address of an index expression. - // If we've already recorded base address, then just give up on this SCEV - // - it's too complicated. - if (BaseAddress) { - IndexIsConstant = false; - return false; - } - BaseAddress = SC->getValue(); - return false; - } - if (isa<SCEVConstant>(S)) - return false; - if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) { - // If the current SCEV expression is AddRec, and its loop isn't the loop - // we are about to unroll, then we won't get a constant address after - // unrolling, and thus, won't be able to eliminate the load. - if (AR->getLoop() != L) { - IndexIsConstant = false; - return false; - } - // We don't handle multiple AddRecs here, so give up in this case. - if (HaveSeenAR) { - IndexIsConstant = false; - return false; - } - HaveSeenAR = true; - } - - // Continue traversal. - return true; - } - bool isDone() const { return !IndexIsConstant; } -}; -} // End anonymous namespace. - -namespace { -/// \brief A cache of SCEV results used to optimize repeated queries to SCEV on -/// the same set of instructions. -/// -/// The primary cost this saves is the cost of checking the validity of a SCEV -/// every time it is looked up. However, in some cases we can provide a reduced -/// and especially useful model for an instruction based upon SCEV that is -/// non-trivial to compute but more useful to clients. -class SCEVCache { -public: - /// \brief Struct to represent a GEP whose start and step are known fixed - /// offsets from a base address due to SCEV's analysis. - struct GEPDescriptor { - Value *BaseAddr = nullptr; - unsigned Start = 0; - unsigned Step = 0; - }; - - Optional<GEPDescriptor> getGEPDescriptor(GetElementPtrInst *GEP); - - SCEVCache(const Loop &L, ScalarEvolution &SE) : L(L), SE(SE) {} - -private: - const Loop &L; - ScalarEvolution &SE; - - SmallDenseMap<GetElementPtrInst *, GEPDescriptor> GEPDescriptors; -}; -} // End anonymous namespace. - -/// \brief Get a simplified descriptor for a GEP instruction. -/// -/// Where possible, this produces a simplified descriptor for a GEP instruction -/// using SCEV analysis of the containing loop. If this isn't possible, it -/// returns an empty optional. -/// -/// The model is a base address, an initial offset, and a per-iteration step. -/// This fits very common patterns of GEPs inside loops and is something we can -/// use to simulate the behavior of a particular iteration of a loop. -/// -/// This is a cached interface. The first call may do non-trivial work to -/// compute the result, but all subsequent calls will return a fast answer -/// based on a cached result. This includes caching negative results. -Optional<SCEVCache::GEPDescriptor> -SCEVCache::getGEPDescriptor(GetElementPtrInst *GEP) { - decltype(GEPDescriptors)::iterator It; - bool Inserted; - - std::tie(It, Inserted) = GEPDescriptors.insert({GEP, {}}); - - if (!Inserted) { - if (!It->second.BaseAddr) - return None; - - return It->second; - } - - // We've inserted a new record into the cache, so compute the GEP descriptor - // if possible. - Value *V = cast<Value>(GEP); - if (!SE.isSCEVable(V->getType())) - return None; - const SCEV *S = SE.getSCEV(V); - - // FIXME: It'd be nice if the worklist and set used by the - // SCEVTraversal could be re-used between loop iterations, but the - // interface doesn't support that. There is no way to clear the visited - // sets between uses. - FindConstantPointers Visitor(&L, SE); - SCEVTraversal<FindConstantPointers> T(Visitor); - - // Try to find (BaseAddress+Step+Offset) tuple. - // If succeeded, save it to the cache - it might help in folding - // loads. - T.visitAll(S); - if (!Visitor.IndexIsConstant || !Visitor.BaseAddress) - return None; - - const SCEV *BaseAddrSE = SE.getSCEV(Visitor.BaseAddress); - if (BaseAddrSE->getType() != S->getType()) - return None; - const SCEV *OffSE = SE.getMinusSCEV(S, BaseAddrSE); - const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(OffSE); - - if (!AR) - return None; - - const SCEVConstant *StepSE = - dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE)); - const SCEVConstant *StartSE = dyn_cast<SCEVConstant>(AR->getStart()); - if (!StepSE || !StartSE) - return None; - - // Check and skip caching if doing so would require lots of bits to - // avoid overflow. - APInt Start = StartSE->getValue()->getValue(); - APInt Step = StepSE->getValue()->getValue(); - if (Start.getActiveBits() > 32 || Step.getActiveBits() > 32) - return None; - - // We found a cacheable SCEV model for the GEP. - It->second.BaseAddr = Visitor.BaseAddress; - It->second.Start = Start.getLimitedValue(); - It->second.Step = Step.getLimitedValue(); - return It->second; -} - -namespace { // This class is used to get an estimate of the optimization effects that we // could get from complete loop unrolling. It comes from the fact that some // loads might be replaced with concrete constant values and that could trigger @@ -446,17 +270,31 @@ namespace { class UnrolledInstAnalyzer : private InstVisitor<UnrolledInstAnalyzer, bool> { typedef InstVisitor<UnrolledInstAnalyzer, bool> Base; friend class InstVisitor<UnrolledInstAnalyzer, bool>; + struct SimplifiedAddress { + Value *Base = nullptr; + ConstantInt *Offset = nullptr; + }; public: UnrolledInstAnalyzer(unsigned Iteration, DenseMap<Value *, Constant *> &SimplifiedValues, - SCEVCache &SC) - : Iteration(Iteration), SimplifiedValues(SimplifiedValues), SC(SC) {} + const Loop *L, ScalarEvolution &SE) + : Iteration(Iteration), SimplifiedValues(SimplifiedValues), L(L), SE(SE) { + IterationNumber = SE.getConstant(APInt(64, Iteration)); + } // Allow access to the initial visit method. using Base::visit; private: + /// \brief A cache of pointer bases and constant-folded offsets corresponding + /// to GEP (or derived from GEP) instructions. + /// + /// In order to find the base pointer one needs to perform non-trivial + /// traversal of the corresponding SCEV expression, so it's good to have the + /// results saved. + DenseMap<Value *, SimplifiedAddress> SimplifiedAddresses; + /// \brief Number of currently simulated iteration. /// /// If an expression is ConstAddress+Constant, then the Constant is @@ -464,18 +302,71 @@ private: /// SCEVGEPCache. unsigned Iteration; - // While we walk the loop instructions, we we build up and maintain a mapping - // of simplified values specific to this iteration. The idea is to propagate - // any special information we have about loads that can be replaced with - // constants after complete unrolling, and account for likely simplifications - // post-unrolling. + /// \brief SCEV expression corresponding to number of currently simulated + /// iteration. + const SCEV *IterationNumber; + + /// \brief A Value->Constant map for keeping values that we managed to + /// constant-fold on the given iteration. + /// + /// While we walk the loop instructions, we build up and maintain a mapping + /// of simplified values specific to this iteration. The idea is to propagate + /// any special information we have about loads that can be replaced with + /// constants after complete unrolling, and account for likely simplifications + /// post-unrolling. DenseMap<Value *, Constant *> &SimplifiedValues; - // We use a cache to wrap all our SCEV queries. - SCEVCache &SC; + const Loop *L; + ScalarEvolution &SE; + + /// \brief Try to simplify instruction \param I using its SCEV expression. + /// + /// The idea is that some AddRec expressions become constants, which then + /// could trigger folding of other instructions. However, that only happens + /// for expressions whose start value is also constant, which isn't always the + /// case. In another common and important case the start value is just some + /// address (i.e. SCEVUnknown) - in this case we compute the offset and save + /// it along with the base address instead. + bool simplifyInstWithSCEV(Instruction *I) { + if (!SE.isSCEVable(I->getType())) + return false; + + const SCEV *S = SE.getSCEV(I); + if (auto *SC = dyn_cast<SCEVConstant>(S)) { + SimplifiedValues[I] = SC->getValue(); + return true; + } + + auto *AR = dyn_cast<SCEVAddRecExpr>(S); + if (!AR) + return false; + + const SCEV *ValueAtIteration = AR->evaluateAtIteration(IterationNumber, SE); + // Check if the AddRec expression becomes a constant. + if (auto *SC = dyn_cast<SCEVConstant>(ValueAtIteration)) { + SimplifiedValues[I] = SC->getValue(); + return true; + } + + // Check if the offset from the base address becomes a constant. + auto *Base = dyn_cast<SCEVUnknown>(SE.getPointerBase(S)); + if (!Base) + return false; + auto *Offset = + dyn_cast<SCEVConstant>(SE.getMinusSCEV(ValueAtIteration, Base)); + if (!Offset) + return false; + SimplifiedAddress Address; + Address.Base = Base->getValue(); + Address.Offset = Offset->getValue(); + SimplifiedAddresses[I] = Address; + return true; + } /// Base case for the instruction visitor. - bool visitInstruction(Instruction &I) { return false; }; + bool visitInstruction(Instruction &I) { + return simplifyInstWithSCEV(&I); + } /// TODO: Add visitors for other instruction types, e.g. ZExt, SExt. @@ -492,6 +383,7 @@ private: if (!isa<Constant>(RHS)) if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) RHS = SimpleRHS; + Value *SimpleV = nullptr; const DataLayout &DL = I.getModule()->getDataLayout(); if (auto FI = dyn_cast<FPMathOperator>(&I)) @@ -503,24 +395,21 @@ private: if (Constant *C = dyn_cast_or_null<Constant>(SimpleV)) SimplifiedValues[&I] = C; - return SimpleV; + if (SimpleV) + return true; + return Base::visitBinaryOperator(I); } /// Try to fold load I. bool visitLoad(LoadInst &I) { Value *AddrOp = I.getPointerOperand(); - if (!isa<Constant>(AddrOp)) - if (Constant *SimplifiedAddrOp = SimplifiedValues.lookup(AddrOp)) - AddrOp = SimplifiedAddrOp; - auto *GEP = dyn_cast<GetElementPtrInst>(AddrOp); - if (!GEP) - return false; - auto OptionalGEPDesc = SC.getGEPDescriptor(GEP); - if (!OptionalGEPDesc) + auto AddressIt = SimplifiedAddresses.find(AddrOp); + if (AddressIt == SimplifiedAddresses.end()) return false; + ConstantInt *SimplifiedAddrOp = AddressIt->second.Offset; - auto GV = dyn_cast<GlobalVariable>(OptionalGEPDesc->BaseAddr); + auto *GV = dyn_cast<GlobalVariable>(AddressIt->second.Base); // We're only interested in loads that can be completely folded to a // constant. if (!GV || !GV->hasInitializer()) @@ -531,13 +420,10 @@ private: if (!CDS) return false; - // This calculation should never overflow because we bound Iteration quite - // low and both the start and step are 32-bit integers. We use signed - // integers so that UBSan will catch if a bug sneaks into the code. int ElemSize = CDS->getElementType()->getPrimitiveSizeInBits() / 8U; - int64_t Index = ((int64_t)OptionalGEPDesc->Start + - (int64_t)OptionalGEPDesc->Step * (int64_t)Iteration) / - ElemSize; + assert(SimplifiedAddrOp->getValue().getActiveBits() < 64 && + "Unexpectedly large index value."); + int64_t Index = SimplifiedAddrOp->getSExtValue() / ElemSize; if (Index >= CDS->getNumElements()) { // FIXME: For now we conservatively ignore out of bound accesses, but // we're allowed to perform the optimization in this case. @@ -556,11 +442,12 @@ private: namespace { struct EstimatedUnrollCost { - /// \brief Count the number of optimized instructions. - unsigned NumberOfOptimizedInstructions; + /// \brief The estimated cost after unrolling. + unsigned UnrolledCost; - /// \brief Count the total number of instructions. - unsigned UnrolledLoopSize; + /// \brief The estimated dynamic cost of executing the instructions in the + /// rolled form. + unsigned RolledDynamicCost; }; } @@ -593,12 +480,15 @@ analyzeLoopUnrollCost(const Loop *L, unsigned TripCount, ScalarEvolution &SE, SmallSetVector<BasicBlock *, 16> BBWorklist; DenseMap<Value *, Constant *> SimplifiedValues; - // Use a cache to access SCEV expressions so that we don't pay the cost on - // each iteration. This cache is lazily self-populating. - SCEVCache SC(*L, SE); - - unsigned NumberOfOptimizedInstructions = 0; - unsigned UnrolledLoopSize = 0; + // The estimated cost of the unrolled form of the loop. We try to estimate + // this by simplifying as much as we can while computing the estimate. + unsigned UnrolledCost = 0; + // We also track the estimated dynamic (that is, actually executed) cost in + // the rolled form. This helps identify cases when the savings from unrolling + // aren't just exposing dead control flows, but actual reduced dynamic + // instructions due to the simplifications which we expect to occur after + // unrolling. + unsigned RolledDynamicCost = 0; // Simulate execution of each iteration of the loop counting instructions, // which would be simplified. @@ -606,7 +496,7 @@ analyzeLoopUnrollCost(const Loop *L, unsigned TripCount, ScalarEvolution &SE, // we literally have to go through all loop's iterations. for (unsigned Iteration = 0; Iteration < TripCount; ++Iteration) { SimplifiedValues.clear(); - UnrolledInstAnalyzer Analyzer(Iteration, SimplifiedValues, SC); + UnrolledInstAnalyzer Analyzer(Iteration, SimplifiedValues, L, SE); BBWorklist.clear(); BBWorklist.insert(L->getHeader()); @@ -618,17 +508,20 @@ analyzeLoopUnrollCost(const Loop *L, unsigned TripCount, ScalarEvolution &SE, // it. We don't change the actual IR, just count optimization // opportunities. for (Instruction &I : *BB) { - UnrolledLoopSize += TTI.getUserCost(&I); + unsigned InstCost = TTI.getUserCost(&I); // Visit the instruction to analyze its loop cost after unrolling, - // and if the visitor returns true, then we can optimize this - // instruction away. - if (Analyzer.visit(I)) - NumberOfOptimizedInstructions += TTI.getUserCost(&I); + // and if the visitor returns false, include this instruction in the + // unrolled cost. + if (!Analyzer.visit(I)) + UnrolledCost += InstCost; + + // Also track this instructions expected cost when executing the rolled + // loop form. + RolledDynamicCost += InstCost; // If unrolled body turns out to be too big, bail out. - if (UnrolledLoopSize - NumberOfOptimizedInstructions > - MaxUnrolledLoopSize) + if (UnrolledCost > MaxUnrolledLoopSize) return None; } @@ -640,10 +533,10 @@ analyzeLoopUnrollCost(const Loop *L, unsigned TripCount, ScalarEvolution &SE, // If we found no optimization opportunities on the first iteration, we // won't find them on later ones too. - if (!NumberOfOptimizedInstructions) + if (UnrolledCost == RolledDynamicCost) return None; } - return {{NumberOfOptimizedInstructions, UnrolledLoopSize}}; + return {{UnrolledCost, RolledDynamicCost}}; } /// ApproximateLoopSize - Approximate the size of the loop. @@ -749,46 +642,56 @@ static void SetLoopAlreadyUnrolled(Loop *L) { L->setLoopID(NewLoopID); } -bool LoopUnroll::canUnrollCompletely( - Loop *L, unsigned Threshold, unsigned AbsoluteThreshold, - uint64_t UnrolledSize, unsigned NumberOfOptimizedInstructions, - unsigned PercentOfOptimizedForCompleteUnroll) { +bool LoopUnroll::canUnrollCompletely(Loop *L, unsigned Threshold, + unsigned PercentDynamicCostSavedThreshold, + unsigned DynamicCostSavingsDiscount, + uint64_t UnrolledCost, + uint64_t RolledDynamicCost) { if (Threshold == NoThreshold) { DEBUG(dbgs() << " Can fully unroll, because no threshold is set.\n"); return true; } - if (UnrolledSize <= Threshold) { - DEBUG(dbgs() << " Can fully unroll, because unrolled size: " - << UnrolledSize << "<" << Threshold << "\n"); + if (UnrolledCost <= Threshold) { + DEBUG(dbgs() << " Can fully unroll, because unrolled cost: " + << UnrolledCost << "<" << Threshold << "\n"); return true; } - assert(UnrolledSize && "UnrolledSize can't be 0 at this point."); - unsigned PercentOfOptimizedInstructions = - (uint64_t)NumberOfOptimizedInstructions * 100ull / UnrolledSize; - - if (UnrolledSize <= AbsoluteThreshold && - PercentOfOptimizedInstructions >= PercentOfOptimizedForCompleteUnroll) { - DEBUG(dbgs() << " Can fully unroll, because unrolling will help removing " - << PercentOfOptimizedInstructions - << "% instructions (threshold: " - << PercentOfOptimizedForCompleteUnroll << "%)\n"); - DEBUG(dbgs() << " Unrolled size (" << UnrolledSize - << ") is less than the threshold (" << AbsoluteThreshold - << ").\n"); + assert(UnrolledCost && "UnrolledCost can't be 0 at this point."); + assert(RolledDynamicCost >= UnrolledCost && + "Cannot have a higher unrolled cost than a rolled cost!"); + + // Compute the percentage of the dynamic cost in the rolled form that is + // saved when unrolled. If unrolling dramatically reduces the estimated + // dynamic cost of the loop, we use a higher threshold to allow more + // unrolling. + unsigned PercentDynamicCostSaved = + (uint64_t)(RolledDynamicCost - UnrolledCost) * 100ull / RolledDynamicCost; + + if (PercentDynamicCostSaved >= PercentDynamicCostSavedThreshold && + (int64_t)UnrolledCost - (int64_t)DynamicCostSavingsDiscount <= + (int64_t)Threshold) { + DEBUG(dbgs() << " Can fully unroll, because unrolling will reduce the " + "expected dynamic cost by " << PercentDynamicCostSaved + << "% (threshold: " << PercentDynamicCostSavedThreshold + << "%)\n" + << " and the unrolled cost (" << UnrolledCost + << ") is less than the max threshold (" + << DynamicCostSavingsDiscount << ").\n"); return true; } DEBUG(dbgs() << " Too large to fully unroll:\n"); - DEBUG(dbgs() << " Unrolled size: " << UnrolledSize << "\n"); - DEBUG(dbgs() << " Estimated number of optimized instructions: " - << NumberOfOptimizedInstructions << "\n"); - DEBUG(dbgs() << " Absolute threshold: " << AbsoluteThreshold << "\n"); - DEBUG(dbgs() << " Minimum percent of removed instructions: " - << PercentOfOptimizedForCompleteUnroll << "\n"); - DEBUG(dbgs() << " Threshold for small loops: " << Threshold << "\n"); + DEBUG(dbgs() << " Threshold: " << Threshold << "\n"); + DEBUG(dbgs() << " Max threshold: " << DynamicCostSavingsDiscount << "\n"); + DEBUG(dbgs() << " Percent cost saved threshold: " + << PercentDynamicCostSavedThreshold << "%\n"); + DEBUG(dbgs() << " Unrolled cost: " << UnrolledCost << "\n"); + DEBUG(dbgs() << " Rolled dynamic cost: " << RolledDynamicCost << "\n"); + DEBUG(dbgs() << " Percent cost saved: " << PercentDynamicCostSaved + << "\n"); return false; } @@ -899,9 +802,11 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) { } unsigned Threshold, PartialThreshold; - unsigned AbsoluteThreshold, PercentOfOptimizedForCompleteUnroll; + unsigned PercentDynamicCostSavedThreshold; + unsigned DynamicCostSavingsDiscount; selectThresholds(L, HasPragma, UP, Threshold, PartialThreshold, - AbsoluteThreshold, PercentOfOptimizedForCompleteUnroll); + PercentDynamicCostSavedThreshold, + DynamicCostSavingsDiscount); // Given Count, TripCount and thresholds determine the type of // unrolling which is to be performed. @@ -910,20 +815,18 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) { if (TripCount && Count == TripCount) { Unrolling = Partial; // If the loop is really small, we don't need to run an expensive analysis. - if (canUnrollCompletely( - L, Threshold, AbsoluteThreshold, - UnrolledSize, 0, 100)) { + if (canUnrollCompletely(L, Threshold, 100, DynamicCostSavingsDiscount, + UnrolledSize, UnrolledSize)) { Unrolling = Full; } else { // The loop isn't that small, but we still can fully unroll it if that // helps to remove a significant number of instructions. // To check that, run additional analysis on the loop. - if (Optional<EstimatedUnrollCost> Cost = - analyzeLoopUnrollCost(L, TripCount, *SE, TTI, AbsoluteThreshold)) - if (canUnrollCompletely(L, Threshold, AbsoluteThreshold, - Cost->UnrolledLoopSize, - Cost->NumberOfOptimizedInstructions, - PercentOfOptimizedForCompleteUnroll)) { + if (Optional<EstimatedUnrollCost> Cost = analyzeLoopUnrollCost( + L, TripCount, *SE, TTI, Threshold + DynamicCostSavingsDiscount)) + if (canUnrollCompletely(L, Threshold, PercentDynamicCostSavedThreshold, + DynamicCostSavingsDiscount, Cost->UnrolledCost, + Cost->RolledDynamicCost)) { Unrolling = Full; } } diff --git a/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp index 66d6ac6..2bdf670 100644 --- a/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp @@ -510,7 +510,7 @@ bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) { // Check that nothing touches the dest of the "copy" between // the call and the store. AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); - AliasAnalysis::Location StoreLoc = AA.getLocation(SI); + AliasAnalysis::Location StoreLoc = MemoryLocation::get(SI); for (BasicBlock::iterator I = --BasicBlock::iterator(SI), E = C; I != E; --I) { if (AA.getModRefInfo(&*I, StoreLoc) != AliasAnalysis::NoModRef) { @@ -802,9 +802,8 @@ bool MemCpyOpt::processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep) { // // NOTE: This is conservative, it will stop on any read from the source loc, // not just the defining memcpy. - MemDepResult SourceDep = - MD->getPointerDependencyFrom(AA.getLocationForSource(MDep), - false, M, M->getParent()); + MemDepResult SourceDep = MD->getPointerDependencyFrom( + MemoryLocation::getForSource(MDep), false, M, M->getParent()); if (!SourceDep.isClobber() || SourceDep.getInst() != MDep) return false; @@ -812,7 +811,8 @@ bool MemCpyOpt::processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep) { // source and dest might overlap. We still want to eliminate the intermediate // value, but we have to generate a memmove instead of memcpy. bool UseMemMove = false; - if (!AA.isNoAlias(AA.getLocationForDest(M), AA.getLocationForSource(MDep))) + if (!AA.isNoAlias(MemoryLocation::getForDest(M), + MemoryLocation::getForSource(MDep))) UseMemMove = true; // If all checks passed, then we can transform M. @@ -860,9 +860,8 @@ bool MemCpyOpt::processMemSetMemCpyDependence(MemCpyInst *MemCpy, return false; // Check that there are no other dependencies on the memset destination. - MemDepResult DstDepInfo = - MD->getPointerDependencyFrom(AliasAnalysis::getLocationForDest(MemSet), - false, MemCpy, MemCpy->getParent()); + MemDepResult DstDepInfo = MD->getPointerDependencyFrom( + MemoryLocation::getForDest(MemSet), false, MemCpy, MemCpy->getParent()); if (DstDepInfo.getInst() != MemSet) return false; @@ -998,7 +997,7 @@ bool MemCpyOpt::processMemCpy(MemCpyInst *M) { } } - AliasAnalysis::Location SrcLoc = AliasAnalysis::getLocationForSource(M); + AliasAnalysis::Location SrcLoc = MemoryLocation::getForSource(M); MemDepResult SrcDepInfo = MD->getPointerDependencyFrom(SrcLoc, true, M, M->getParent()); @@ -1047,7 +1046,8 @@ bool MemCpyOpt::processMemMove(MemMoveInst *M) { return false; // See if the pointers alias. - if (!AA.isNoAlias(AA.getLocationForDest(M), AA.getLocationForSource(M))) + if (!AA.isNoAlias(MemoryLocation::getForDest(M), + MemoryLocation::getForSource(M))) return false; DEBUG(dbgs() << "MemCpyOpt: Optimizing memmove -> memcpy: " << *M << "\n"); @@ -1121,8 +1121,8 @@ bool MemCpyOpt::processByValArgument(CallSite CS, unsigned ArgNo) { // NOTE: This is conservative, it will stop on any read from the source loc, // not just the defining memcpy. MemDepResult SourceDep = - MD->getPointerDependencyFrom(AliasAnalysis::getLocationForSource(MDep), - false, CS.getInstruction(), MDep->getParent()); + MD->getPointerDependencyFrom(MemoryLocation::getForSource(MDep), false, + CS.getInstruction(), MDep->getParent()); if (!SourceDep.isClobber() || SourceDep.getInst() != MDep) return false; diff --git a/contrib/llvm/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp b/contrib/llvm/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp index 611a941..776dfb4 100644 --- a/contrib/llvm/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp @@ -241,7 +241,7 @@ bool MergedLoadStoreMotion::isDiamondHead(BasicBlock *BB) { bool MergedLoadStoreMotion::isLoadHoistBarrierInRange(const Instruction& Start, const Instruction& End, LoadInst* LI) { - AliasAnalysis::Location Loc = AA->getLocation(LI); + AliasAnalysis::Location Loc = MemoryLocation::get(LI); return AA->canInstructionRangeModRef(Start, End, Loc, AliasAnalysis::Mod); } @@ -266,8 +266,8 @@ LoadInst *MergedLoadStoreMotion::canHoistFromBlock(BasicBlock *BB1, LoadInst *Load1 = dyn_cast<LoadInst>(Inst); BasicBlock *BB0 = Load0->getParent(); - AliasAnalysis::Location Loc0 = AA->getLocation(Load0); - AliasAnalysis::Location Loc1 = AA->getLocation(Load1); + AliasAnalysis::Location Loc0 = MemoryLocation::get(Load0); + AliasAnalysis::Location Loc1 = MemoryLocation::get(Load1); if (AA->isMustAlias(Loc0, Loc1) && Load0->isSameOperationAs(Load1) && !isLoadHoistBarrierInRange(BB1->front(), *Load1, Load1) && !isLoadHoistBarrierInRange(BB0->front(), *Load0, Load0)) { @@ -425,8 +425,8 @@ StoreInst *MergedLoadStoreMotion::canSinkFromBlock(BasicBlock *BB1, StoreInst *Store1 = cast<StoreInst>(Inst); - AliasAnalysis::Location Loc0 = AA->getLocation(Store0); - AliasAnalysis::Location Loc1 = AA->getLocation(Store1); + AliasAnalysis::Location Loc0 = MemoryLocation::get(Store0); + AliasAnalysis::Location Loc1 = MemoryLocation::get(Store1); if (AA->isMustAlias(Loc0, Loc1) && Store0->isSameOperationAs(Store1) && !isStoreSinkBarrierInRange(*(std::next(BasicBlock::iterator(Store1))), BB1->back(), Loc1) && diff --git a/contrib/llvm/lib/Transforms/Scalar/NaryReassociate.cpp b/contrib/llvm/lib/Transforms/Scalar/NaryReassociate.cpp index 5b370e0..4cf68b0 100644 --- a/contrib/llvm/lib/Transforms/Scalar/NaryReassociate.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/NaryReassociate.cpp @@ -234,6 +234,7 @@ bool NaryReassociate::doOneIteration(Function &F) { BasicBlock *BB = Node->getBlock(); for (auto I = BB->begin(); I != BB->end(); ++I) { if (SE->isSCEVable(I->getType()) && isPotentiallyNaryReassociable(I)) { + const SCEV *OldSCEV = SE->getSCEV(I); if (Instruction *NewI = tryReassociate(I)) { Changed = true; SE->forgetValue(I); @@ -243,7 +244,28 @@ bool NaryReassociate::doOneIteration(Function &F) { } // Add the rewritten instruction to SeenExprs; the original instruction // is deleted. - SeenExprs[SE->getSCEV(I)].push_back(I); + const SCEV *NewSCEV = SE->getSCEV(I); + SeenExprs[NewSCEV].push_back(I); + // Ideally, NewSCEV should equal OldSCEV because tryReassociate(I) + // is equivalent to I. However, ScalarEvolution::getSCEV may + // weaken nsw causing NewSCEV not to equal OldSCEV. For example, suppose + // we reassociate + // I = &a[sext(i +nsw j)] // assuming sizeof(a[0]) = 4 + // to + // NewI = &a[sext(i)] + sext(j). + // + // ScalarEvolution computes + // getSCEV(I) = a + 4 * sext(i + j) + // getSCEV(newI) = a + 4 * sext(i) + 4 * sext(j) + // which are different SCEVs. + // + // To alleviate this issue of ScalarEvolution not always capturing + // equivalence, we add I to SeenExprs[OldSCEV] as well so that we can + // map both SCEV before and after tryReassociate(I) to I. + // + // This improvement is exercised in @reassociate_gep_nsw in nary-gep.ll. + if (NewSCEV != OldSCEV) + SeenExprs[OldSCEV].push_back(I); } } } @@ -295,8 +317,10 @@ static bool isGEPFoldable(GetElementPtrInst *GEP, BaseOffset += DL->getStructLayout(STy)->getElementOffset(Field); } } + + unsigned AddrSpace = GEP->getPointerAddressSpace(); return TTI->isLegalAddressingMode(GEP->getType()->getElementType(), BaseGV, - BaseOffset, HasBaseReg, Scale); + BaseOffset, HasBaseReg, Scale, AddrSpace); } Instruction *NaryReassociate::tryReassociateGEP(GetElementPtrInst *GEP) { diff --git a/contrib/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp b/contrib/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp index 3e7deeb..9ecaf10 100644 --- a/contrib/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp @@ -496,7 +496,7 @@ template <typename T> static void unique_unsorted(std::vector<T> &vec) { } } -static std::string GCSafepointPollName("gc.safepoint_poll"); +static const char *const GCSafepointPollName = "gc.safepoint_poll"; static bool isGCSafepointPoll(Function &F) { return F.getName().equals(GCSafepointPollName); diff --git a/contrib/llvm/lib/Transforms/Scalar/Reassociate.cpp b/contrib/llvm/lib/Transforms/Scalar/Reassociate.cpp index b677523..6c66b58 100644 --- a/contrib/llvm/lib/Transforms/Scalar/Reassociate.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/Reassociate.cpp @@ -733,7 +733,7 @@ static bool LinearizeExprTree(BinaryOperator *I, if (Ops.empty()) { Constant *Identity = ConstantExpr::getBinOpIdentity(Opcode, I->getType()); assert(Identity && "Associative operation without identity!"); - Ops.push_back(std::make_pair(Identity, APInt(Bitwidth, 1))); + Ops.emplace_back(Identity, APInt(Bitwidth, 1)); } return Changed; @@ -1966,38 +1966,35 @@ Instruction *Reassociate::canonicalizeNegConstExpr(Instruction *I) { if (!I->hasOneUse() || I->getType()->isVectorTy()) return nullptr; - // Must be a mul, fmul, or fdiv instruction. + // Must be a fmul or fdiv instruction. unsigned Opcode = I->getOpcode(); - if (Opcode != Instruction::Mul && Opcode != Instruction::FMul && - Opcode != Instruction::FDiv) + if (Opcode != Instruction::FMul && Opcode != Instruction::FDiv) return nullptr; - // Must have at least one constant operand. - Constant *C0 = dyn_cast<Constant>(I->getOperand(0)); - Constant *C1 = dyn_cast<Constant>(I->getOperand(1)); - if (!C0 && !C1) + auto *C0 = dyn_cast<ConstantFP>(I->getOperand(0)); + auto *C1 = dyn_cast<ConstantFP>(I->getOperand(1)); + + // Both operands are constant, let it get constant folded away. + if (C0 && C1) return nullptr; - // Must be a negative ConstantInt or ConstantFP. - Constant *C = C0 ? C0 : C1; - unsigned ConstIdx = C0 ? 0 : 1; - if (auto *CI = dyn_cast<ConstantInt>(C)) { - if (!CI->isNegative() || CI->isMinValue(true)) - return nullptr; - } else if (auto *CF = dyn_cast<ConstantFP>(C)) { - if (!CF->isNegative()) - return nullptr; - } else + ConstantFP *CF = C0 ? C0 : C1; + + // Must have one constant operand. + if (!CF) + return nullptr; + + // Must be a negative ConstantFP. + if (!CF->isNegative()) return nullptr; // User must be a binary operator with one or more uses. Instruction *User = I->user_back(); - if (!isa<BinaryOperator>(User) || !User->getNumUses()) + if (!isa<BinaryOperator>(User) || !User->hasNUsesOrMore(1)) return nullptr; unsigned UserOpcode = User->getOpcode(); - if (UserOpcode != Instruction::Add && UserOpcode != Instruction::FAdd && - UserOpcode != Instruction::Sub && UserOpcode != Instruction::FSub) + if (UserOpcode != Instruction::FAdd && UserOpcode != Instruction::FSub) return nullptr; // Subtraction is not commutative. Explicitly, the following transform is @@ -2006,14 +2003,9 @@ Instruction *Reassociate::canonicalizeNegConstExpr(Instruction *I) { return nullptr; // Change the sign of the constant. - if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) - I->setOperand(ConstIdx, ConstantInt::get(CI->getContext(), -CI->getValue())); - else { - ConstantFP *CF = cast<ConstantFP>(C); - APFloat Val = CF->getValueAPF(); - Val.changeSign(); - I->setOperand(ConstIdx, ConstantFP::get(CF->getContext(), Val)); - } + APFloat Val = CF->getValueAPF(); + Val.changeSign(); + I->setOperand(C0 ? 0 : 1, ConstantFP::get(CF->getContext(), Val)); // Canonicalize I to RHS to simplify the next bit of logic. E.g., // ((-Const*y) + x) -> (x + (-Const*y)). @@ -2023,15 +2015,9 @@ Instruction *Reassociate::canonicalizeNegConstExpr(Instruction *I) { Value *Op0 = User->getOperand(0); Value *Op1 = User->getOperand(1); BinaryOperator *NI; - switch(UserOpcode) { + switch (UserOpcode) { default: llvm_unreachable("Unexpected Opcode!"); - case Instruction::Add: - NI = BinaryOperator::CreateSub(Op0, Op1); - break; - case Instruction::Sub: - NI = BinaryOperator::CreateAdd(Op0, Op1); - break; case Instruction::FAdd: NI = BinaryOperator::CreateFSub(Op0, Op1); NI->setFastMathFlags(cast<FPMathOperator>(User)->getFastMathFlags()); diff --git a/contrib/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/contrib/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp index 6cf765a..6f6ba72 100644 --- a/contrib/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp @@ -30,6 +30,7 @@ #include "llvm/IR/Intrinsics.h" #include "llvm/IR/IntrinsicInst.h" #include "llvm/IR/Module.h" +#include "llvm/IR/MDBuilder.h" #include "llvm/IR/Statepoint.h" #include "llvm/IR/Value.h" #include "llvm/IR/Verifier.h" @@ -74,13 +75,27 @@ static cl::opt<bool, true> ClobberNonLiveOverride("rs4gc-clobber-non-live", cl::Hidden); namespace { -struct RewriteStatepointsForGC : public FunctionPass { +struct RewriteStatepointsForGC : public ModulePass { static char ID; // Pass identification, replacement for typeid - RewriteStatepointsForGC() : FunctionPass(ID) { + RewriteStatepointsForGC() : ModulePass(ID) { initializeRewriteStatepointsForGCPass(*PassRegistry::getPassRegistry()); } - bool runOnFunction(Function &F) override; + bool runOnFunction(Function &F); + bool runOnModule(Module &M) override { + bool Changed = false; + for (Function &F : M) + Changed |= runOnFunction(F); + + if (Changed) { + // stripDereferenceabilityInfo asserts that shouldRewriteStatepointsIn + // returns true for at least one function in the module. Since at least + // one function changed, we know that the precondition is satisfied. + stripDereferenceabilityInfo(M); + } + + return Changed; + } void getAnalysisUsage(AnalysisUsage &AU) const override { // We add and rewrite a bunch of instructions, but don't really do much @@ -88,12 +103,26 @@ struct RewriteStatepointsForGC : public FunctionPass { AU.addRequired<DominatorTreeWrapperPass>(); AU.addRequired<TargetTransformInfoWrapperPass>(); } + + /// The IR fed into RewriteStatepointsForGC may have had attributes implying + /// dereferenceability that are no longer valid/correct after + /// RewriteStatepointsForGC has run. This is because semantically, after + /// RewriteStatepointsForGC runs, all calls to gc.statepoint "free" the entire + /// heap. stripDereferenceabilityInfo (conservatively) restores correctness + /// by erasing all attributes in the module that externally imply + /// dereferenceability. + /// + void stripDereferenceabilityInfo(Module &M); + + // Helpers for stripDereferenceabilityInfo + void stripDereferenceabilityInfoFromBody(Function &F); + void stripDereferenceabilityInfoFromPrototype(Function &F); }; } // namespace char RewriteStatepointsForGC::ID = 0; -FunctionPass *llvm::createRewriteStatepointsForGCPass() { +ModulePass *llvm::createRewriteStatepointsForGCPass() { return new RewriteStatepointsForGC(); } @@ -1031,14 +1060,11 @@ static void recomputeLiveInValues( // goes through the statepoint. We might need to split an edge to make this // possible. static BasicBlock * -normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent, Pass *P) { - DominatorTree *DT = nullptr; - if (auto *DTP = P->getAnalysisIfAvailable<DominatorTreeWrapperPass>()) - DT = &DTP->getDomTree(); - +normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent, + DominatorTree &DT) { BasicBlock *Ret = BB; if (!BB->getUniquePredecessor()) { - Ret = SplitBlockPredecessors(BB, InvokeParent, "", nullptr, DT); + Ret = SplitBlockPredecessors(BB, InvokeParent, "", nullptr, &DT); } // Now that 'ret' has unique predecessor we can safely remove all phi nodes @@ -2016,9 +2042,9 @@ static bool insertParsePoints(Function &F, DominatorTree &DT, Pass *P, continue; InvokeInst *invoke = cast<InvokeInst>(CS.getInstruction()); normalizeForInvokeSafepoint(invoke->getNormalDest(), invoke->getParent(), - P); + DT); normalizeForInvokeSafepoint(invoke->getUnwindDest(), invoke->getParent(), - P); + DT); } // A list of dummy calls added to the IR to keep various values obviously @@ -2197,6 +2223,72 @@ static bool insertParsePoints(Function &F, DominatorTree &DT, Pass *P, return !records.empty(); } +// Handles both return values and arguments for Functions and CallSites. +template <typename AttrHolder> +static void RemoveDerefAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH, + unsigned Index) { + AttrBuilder R; + if (AH.getDereferenceableBytes(Index)) + R.addAttribute(Attribute::get(Ctx, Attribute::Dereferenceable, + AH.getDereferenceableBytes(Index))); + if (AH.getDereferenceableOrNullBytes(Index)) + R.addAttribute(Attribute::get(Ctx, Attribute::DereferenceableOrNull, + AH.getDereferenceableOrNullBytes(Index))); + + if (!R.empty()) + AH.setAttributes(AH.getAttributes().removeAttributes( + Ctx, Index, AttributeSet::get(Ctx, Index, R))); +} + +void +RewriteStatepointsForGC::stripDereferenceabilityInfoFromPrototype(Function &F) { + LLVMContext &Ctx = F.getContext(); + + for (Argument &A : F.args()) + if (isa<PointerType>(A.getType())) + RemoveDerefAttrAtIndex(Ctx, F, A.getArgNo() + 1); + + if (isa<PointerType>(F.getReturnType())) + RemoveDerefAttrAtIndex(Ctx, F, AttributeSet::ReturnIndex); +} + +void RewriteStatepointsForGC::stripDereferenceabilityInfoFromBody(Function &F) { + if (F.empty()) + return; + + LLVMContext &Ctx = F.getContext(); + MDBuilder Builder(Ctx); + + for (Instruction &I : inst_range(F)) { + if (const MDNode *MD = I.getMetadata(LLVMContext::MD_tbaa)) { + assert(MD->getNumOperands() < 5 && "unrecognized metadata shape!"); + bool IsImmutableTBAA = + MD->getNumOperands() == 4 && + mdconst::extract<ConstantInt>(MD->getOperand(3))->getValue() == 1; + + if (!IsImmutableTBAA) + continue; // no work to do, MD_tbaa is already marked mutable + + MDNode *Base = cast<MDNode>(MD->getOperand(0)); + MDNode *Access = cast<MDNode>(MD->getOperand(1)); + uint64_t Offset = + mdconst::extract<ConstantInt>(MD->getOperand(2))->getZExtValue(); + + MDNode *MutableTBAA = + Builder.createTBAAStructTagNode(Base, Access, Offset); + I.setMetadata(LLVMContext::MD_tbaa, MutableTBAA); + } + + if (CallSite CS = CallSite(&I)) { + for (int i = 0, e = CS.arg_size(); i != e; i++) + if (isa<PointerType>(CS.getArgument(i)->getType())) + RemoveDerefAttrAtIndex(Ctx, CS, i + 1); + if (isa<PointerType>(CS.getType())) + RemoveDerefAttrAtIndex(Ctx, CS, AttributeSet::ReturnIndex); + } + } +} + /// Returns true if this function should be rewritten by this pass. The main /// point of this function is as an extension point for custom logic. static bool shouldRewriteStatepointsIn(Function &F) { @@ -2211,6 +2303,19 @@ static bool shouldRewriteStatepointsIn(Function &F) { return false; } +void RewriteStatepointsForGC::stripDereferenceabilityInfo(Module &M) { +#ifndef NDEBUG + assert(std::any_of(M.begin(), M.end(), shouldRewriteStatepointsIn) && + "precondition!"); +#endif + + for (Function &F : M) + stripDereferenceabilityInfoFromPrototype(F); + + for (Function &F : M) + stripDereferenceabilityInfoFromBody(F); +} + bool RewriteStatepointsForGC::runOnFunction(Function &F) { // Nothing to do for declarations. if (F.isDeclaration() || F.empty()) @@ -2221,7 +2326,7 @@ bool RewriteStatepointsForGC::runOnFunction(Function &F) { if (!shouldRewriteStatepointsIn(F)) return false; - DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree(); + DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); // Gather all the statepoints which need rewritten. Be careful to only // consider those in reachable code since we need to ask dominance queries diff --git a/contrib/llvm/lib/Transforms/Scalar/SeparateConstOffsetFromGEP.cpp b/contrib/llvm/lib/Transforms/Scalar/SeparateConstOffsetFromGEP.cpp index 3a782d1..4a87531 100644 --- a/contrib/llvm/lib/Transforms/Scalar/SeparateConstOffsetFromGEP.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/SeparateConstOffsetFromGEP.cpp @@ -852,9 +852,11 @@ bool SeparateConstOffsetFromGEP::splitGEP(GetElementPtrInst *GEP) { TargetTransformInfo &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI( *GEP->getParent()->getParent()); + unsigned AddrSpace = GEP->getPointerAddressSpace(); if (!TTI.isLegalAddressingMode(GEP->getType()->getElementType(), /*BaseGV=*/nullptr, AccumulativeByteOffset, - /*HasBaseReg=*/true, /*Scale=*/0)) { + /*HasBaseReg=*/true, /*Scale=*/0, + AddrSpace)) { return Changed; } } diff --git a/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp index 8566cd9..f0e3ffd 100644 --- a/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp @@ -193,11 +193,18 @@ namespace { struct CFGSimplifyPass : public FunctionPass { static char ID; // Pass identification, replacement for typeid unsigned BonusInstThreshold; - CFGSimplifyPass(int T = -1) : FunctionPass(ID) { + std::function<bool(const Function &)> PredicateFtor; + + CFGSimplifyPass(int T = -1, + std::function<bool(const Function &)> Ftor = nullptr) + : FunctionPass(ID), PredicateFtor(Ftor) { BonusInstThreshold = (T == -1) ? UserBonusInstThreshold : unsigned(T); initializeCFGSimplifyPassPass(*PassRegistry::getPassRegistry()); } bool runOnFunction(Function &F) override { + if (PredicateFtor && !PredicateFtor(F)) + return false; + if (skipOptnoneFunction(F)) return false; @@ -224,7 +231,9 @@ INITIALIZE_PASS_END(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false, false) // Public interface to the CFGSimplification pass -FunctionPass *llvm::createCFGSimplificationPass(int Threshold) { - return new CFGSimplifyPass(Threshold); +FunctionPass * +llvm::createCFGSimplificationPass(int Threshold, + std::function<bool(const Function &)> Ftor) { + return new CFGSimplifyPass(Threshold, Ftor); } diff --git a/contrib/llvm/lib/Transforms/Scalar/Sink.cpp b/contrib/llvm/lib/Transforms/Scalar/Sink.cpp index b169d56..078c6a9 100644 --- a/contrib/llvm/lib/Transforms/Scalar/Sink.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/Sink.cpp @@ -163,7 +163,7 @@ static bool isSafeToMove(Instruction *Inst, AliasAnalysis *AA, } if (LoadInst *L = dyn_cast<LoadInst>(Inst)) { - AliasAnalysis::Location Loc = AA->getLocation(L); + AliasAnalysis::Location Loc = MemoryLocation::get(L); for (Instruction *S : Stores) if (AA->getModRefInfo(S, Loc) & AliasAnalysis::Mod) return false; @@ -172,6 +172,12 @@ static bool isSafeToMove(Instruction *Inst, AliasAnalysis *AA, if (isa<TerminatorInst>(Inst) || isa<PHINode>(Inst)) return false; + // Convergent operations can only be moved to control equivalent blocks. + if (auto CS = CallSite(Inst)) { + if (CS.hasFnAttr(Attribute::Convergent)) + return false; + } + return true; } |
