diff options
| -rw-r--r-- | llvm/lib/Transforms/Utils/MemorySSA.cpp | 16 | ||||
| -rw-r--r-- | llvm/test/Transforms/Util/MemorySSA/function-clobber.ll | 27 |
2 files changed, 38 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/Utils/MemorySSA.cpp b/llvm/lib/Transforms/Utils/MemorySSA.cpp index b71c1945a0e..1ce8970c78e 100644 --- a/llvm/lib/Transforms/Utils/MemorySSA.cpp +++ b/llvm/lib/Transforms/Utils/MemorySSA.cpp @@ -763,11 +763,11 @@ struct CachingMemorySSAWalker::UpwardsMemoryQuery { const Instruction *Inst; // Set of visited Instructions for this query. DenseSet<MemoryAccessPair> Visited; - // Set of visited call accesses for this query. This is separated out because - // you can always cache and lookup the result of call queries (IE when IsCall - // == true) for every call in the chain. The calls have no AA location + // Vector of visited call accesses for this query. This is separated out + // because you can always cache and lookup the result of call queries (IE when + // IsCall == true) for every call in the chain. The calls have no AA location // associated with them with them, and thus, no context dependence. - SmallPtrSet<const MemoryAccess *, 32> VisitedCalls; + SmallVector<const MemoryAccess *, 32> VisitedCalls; // The MemoryAccess we actually got called with, used to test local domination const MemoryAccess *OriginalAccess; // The Datalayout for the module we started in @@ -862,7 +862,7 @@ bool CachingMemorySSAWalker::instructionClobbersQuery( // If this is a call, mark it for caching if (ImmutableCallSite(DefMemoryInst)) - Q.VisitedCalls.insert(MD); + Q.VisitedCalls.push_back(MD); ModRefInfo I = AA->getModRefInfo(DefMemoryInst, ImmutableCallSite(Q.Inst)); return I != MRI_NoModRef; } @@ -918,6 +918,8 @@ MemoryAccessPair CachingMemorySSAWalker::UpwardsDFSWalk( break; } + std::size_t InitialVisitedCallSize = Q.VisitedCalls.size(); + // Recurse on PHI nodes, since we need to change locations. // TODO: Allow graphtraits on pairs, which would turn this whole function // into a normal single depth first walk. @@ -947,6 +949,10 @@ MemoryAccessPair CachingMemorySSAWalker::UpwardsDFSWalk( if (!ModifyingAccess) { assert(FirstDef && "Found a Phi with no upward defs?"); ModifyingAccess = FirstDef; + } else { + // If we can't optimize this Phi, then we can't safely cache any of the + // calls we visited when trying to optimize it. Wipe them out now. + Q.VisitedCalls.resize(InitialVisitedCallSize); } break; } diff --git a/llvm/test/Transforms/Util/MemorySSA/function-clobber.ll b/llvm/test/Transforms/Util/MemorySSA/function-clobber.ll index 97e231a4ea2..937ab245191 100644 --- a/llvm/test/Transforms/Util/MemorySSA/function-clobber.ll +++ b/llvm/test/Transforms/Util/MemorySSA/function-clobber.ll @@ -24,3 +24,30 @@ define i32 @foo() { %3 = add i32 %2, %1 ret i32 %3 } + +declare void @readEverything() readonly +declare void @clobberEverything() + +; CHECK-LABEL: define void @bar +define void @bar() { +; CHECK: 1 = MemoryDef(liveOnEntry) +; CHECK-NEXT: call void @clobberEverything() + call void @clobberEverything() + br i1 undef, label %if.end, label %if.then + +if.then: +; CHECK: MemoryUse(1) +; CHECK-NEXT: call void @readEverything() + call void @readEverything() +; CHECK: 2 = MemoryDef(1) +; CHECK-NEXT: call void @clobberEverything() + call void @clobberEverything() + br label %if.end + +if.end: +; CHECK: 3 = MemoryPhi({%0,1},{if.then,2}) +; CHECK: MemoryUse(3) +; CHECK-NEXT: call void @readEverything() + call void @readEverything() + ret void +} |
