Index: llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp =================================================================== --- llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp +++ llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp @@ -40,6 +40,7 @@ #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/CaptureTracking.h" #include "llvm/Analysis/GlobalsModRef.h" +#include "llvm/Analysis/LoopInfo.h" #include "llvm/Analysis/MemoryBuiltins.h" #include "llvm/Analysis/MemoryLocation.h" #include "llvm/Analysis/MemorySSA.h" @@ -1294,7 +1295,7 @@ getDomMemoryDef(MemoryDef *KillingDef, MemoryAccess *StartAccess, const MemoryLocation &DefLoc, const Value *DefUO, unsigned &ScanLimit, unsigned &WalkerStepLimit, - bool IsMemTerm, unsigned &PartialLimit) { + bool IsMemTerm, unsigned &PartialLimit, LoopInfo &LI) { if (ScanLimit == 0 || WalkerStepLimit == 0) { LLVM_DEBUG(dbgs() << "\n ... hit scan limit\n"); return None; @@ -1402,9 +1403,11 @@ // AliasAnalysis does not account for loops. Limit elimination to // candidates for which we can guarantee they always store to the same - // memory location and not multiple locations in a loop. - if (Current->getBlock() != KillingDef->getBlock() && + // memory location and not located in different loops. + if (LI.getLoopFor(Current->getBlock()) != + LI.getLoopFor(KillingDef->getBlock()) && !IsGuaranteedLoopInvariant(const_cast(CurrentLoc->Ptr))) { + LLVM_DEBUG(dbgs() << " ... not guaranteed loop invariant\n"); StepAgain = true; Current = CurrentDef->getDefiningAccess(); WalkerStepLimit -= 1; @@ -1833,9 +1836,9 @@ } }; -bool eliminateDeadStores(Function &F, AliasAnalysis &AA, MemorySSA &MSSA, - DominatorTree &DT, PostDominatorTree &PDT, - const TargetLibraryInfo &TLI) { +static bool eliminateDeadStores(Function &F, AliasAnalysis &AA, MemorySSA &MSSA, + DominatorTree &DT, PostDominatorTree &PDT, + const TargetLibraryInfo &TLI, LoopInfo &LI) { bool MadeChange = false; DSEState State = DSEState::get(F, AA, MSSA, DT, PDT, TLI); @@ -1883,9 +1886,9 @@ if (State.SkipStores.count(Current)) continue; - Optional Next = State.getDomMemoryDef( - KillingDef, Current, SILoc, SILocUnd, ScanLimit, WalkerStepLimit, - IsMemTerm, PartialLimit); + Optional Next = + State.getDomMemoryDef(KillingDef, Current, SILoc, SILocUnd, ScanLimit, + WalkerStepLimit, IsMemTerm, PartialLimit, LI); if (!Next) { LLVM_DEBUG(dbgs() << " finished walk\n"); @@ -2012,8 +2015,9 @@ DominatorTree &DT = AM.getResult(F); MemorySSA &MSSA = AM.getResult(F).getMSSA(); PostDominatorTree &PDT = AM.getResult(F); + LoopInfo &LI = AM.getResult(F); - bool Changed = eliminateDeadStores(F, AA, MSSA, DT, PDT, TLI); + bool Changed = eliminateDeadStores(F, AA, MSSA, DT, PDT, TLI, LI); #ifdef LLVM_ENABLE_STATS if (AreStatisticsEnabled()) @@ -2053,8 +2057,9 @@ MemorySSA &MSSA = getAnalysis().getMSSA(); PostDominatorTree &PDT = getAnalysis().getPostDomTree(); + LoopInfo &LI = getAnalysis().getLoopInfo(); - bool Changed = eliminateDeadStores(F, AA, MSSA, DT, PDT, TLI); + bool Changed = eliminateDeadStores(F, AA, MSSA, DT, PDT, TLI, LI); #ifdef LLVM_ENABLE_STATS if (AreStatisticsEnabled()) @@ -2076,6 +2081,8 @@ AU.addRequired(); AU.addPreserved(); AU.addPreserved(); + AU.addRequired(); + AU.addPreserved(); } }; Index: llvm/test/CodeGen/AMDGPU/opt-pipeline.ll =================================================================== --- llvm/test/CodeGen/AMDGPU/opt-pipeline.ll +++ llvm/test/CodeGen/AMDGPU/opt-pipeline.ll @@ -523,8 +523,8 @@ ; GCN-O2-NEXT: Function Alias Analysis Results ; GCN-O2-NEXT: Memory SSA ; GCN-O2-NEXT: MemCpy Optimization -; GCN-O2-NEXT: Dead Store Elimination ; GCN-O2-NEXT: Natural Loop Information +; GCN-O2-NEXT: Dead Store Elimination ; GCN-O2-NEXT: Canonicalize natural loops ; GCN-O2-NEXT: LCSSA Verifier ; GCN-O2-NEXT: Loop-Closed SSA Form Pass @@ -886,8 +886,8 @@ ; GCN-O3-NEXT: Function Alias Analysis Results ; GCN-O3-NEXT: Memory SSA ; GCN-O3-NEXT: MemCpy Optimization -; GCN-O3-NEXT: Dead Store Elimination ; GCN-O3-NEXT: Natural Loop Information +; GCN-O3-NEXT: Dead Store Elimination ; GCN-O3-NEXT: Canonicalize natural loops ; GCN-O3-NEXT: LCSSA Verifier ; GCN-O3-NEXT: Loop-Closed SSA Form Pass Index: llvm/test/Other/opt-O2-pipeline.ll =================================================================== --- llvm/test/Other/opt-O2-pipeline.ll +++ llvm/test/Other/opt-O2-pipeline.ll @@ -166,8 +166,8 @@ ; CHECK-NEXT: Function Alias Analysis Results ; CHECK-NEXT: Memory SSA ; CHECK-NEXT: MemCpy Optimization -; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Natural Loop Information +; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Canonicalize natural loops ; CHECK-NEXT: LCSSA Verifier ; CHECK-NEXT: Loop-Closed SSA Form Pass Index: llvm/test/Other/opt-O3-pipeline-enable-matrix.ll =================================================================== --- llvm/test/Other/opt-O3-pipeline-enable-matrix.ll +++ llvm/test/Other/opt-O3-pipeline-enable-matrix.ll @@ -171,8 +171,8 @@ ; CHECK-NEXT: Function Alias Analysis Results ; CHECK-NEXT: Memory SSA ; CHECK-NEXT: MemCpy Optimization -; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Natural Loop Information +; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Canonicalize natural loops ; CHECK-NEXT: LCSSA Verifier ; CHECK-NEXT: Loop-Closed SSA Form Pass Index: llvm/test/Other/opt-O3-pipeline.ll =================================================================== --- llvm/test/Other/opt-O3-pipeline.ll +++ llvm/test/Other/opt-O3-pipeline.ll @@ -171,8 +171,8 @@ ; CHECK-NEXT: Function Alias Analysis Results ; CHECK-NEXT: Memory SSA ; CHECK-NEXT: MemCpy Optimization -; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Natural Loop Information +; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Canonicalize natural loops ; CHECK-NEXT: LCSSA Verifier ; CHECK-NEXT: Loop-Closed SSA Form Pass Index: llvm/test/Other/opt-Os-pipeline.ll =================================================================== --- llvm/test/Other/opt-Os-pipeline.ll +++ llvm/test/Other/opt-Os-pipeline.ll @@ -152,8 +152,8 @@ ; CHECK-NEXT: Function Alias Analysis Results ; CHECK-NEXT: Memory SSA ; CHECK-NEXT: MemCpy Optimization -; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Natural Loop Information +; CHECK-NEXT: Dead Store Elimination ; CHECK-NEXT: Canonicalize natural loops ; CHECK-NEXT: LCSSA Verifier ; CHECK-NEXT: Loop-Closed SSA Form Pass Index: llvm/test/Transforms/DeadStoreElimination/multiblock-loops.ll =================================================================== --- llvm/test/Transforms/DeadStoreElimination/multiblock-loops.ll +++ llvm/test/Transforms/DeadStoreElimination/multiblock-loops.ll @@ -111,7 +111,6 @@ ; CHECK: for.body4.lr.ph: ; CHECK-NEXT: [[I_028:%.*]] = phi i32 [ [[INC11:%.*]], [[FOR_COND_CLEANUP3:%.*]] ], [ 0, [[FOR_BODY4_LR_PH_PREHEADER]] ] ; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, i32* [[B:%.*]], i32 [[I_028]] -; CHECK-NEXT: store i32 0, i32* [[ARRAYIDX]], align 4 ; CHECK-NEXT: [[MUL:%.*]] = mul nsw i32 [[I_028]], [[N]] ; CHECK-NEXT: br label [[FOR_BODY4:%.*]] ; CHECK: for.body4: