diff options
| author | Chris Lattner <sabre@nondot.org> | 2010-02-11 05:11:54 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-02-11 05:11:54 +0000 |
| commit | 98df4f9cf2dea81af1cc2e68f23b285d22cebc6a (patch) | |
| tree | 47c8b84c69a8ce4c6f5dc24df0ded8eac4168e6c | |
| parent | 5cc25ce17d7d730b33803ae23a17c05a39427cce (diff) | |
Make DSE only scan blocks that are reachable from the entry
block. Other blocks may have pointer cycles that will crash
basicaa and other alias analyses. In any case, there is no
point wasting cycles optimizing dead blocks. This fixes
rdar://7635088
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95852 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/Scalar/DeadStoreElimination.cpp | 8 | ||||
| -rw-r--r-- | test/Transforms/DeadStoreElimination/crash.ll | 14 |
2 files changed, 21 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/DeadStoreElimination.cpp b/lib/Transforms/Scalar/DeadStoreElimination.cpp index 320afa19d5..09c01d3141 100644 --- a/lib/Transforms/Scalar/DeadStoreElimination.cpp +++ b/lib/Transforms/Scalar/DeadStoreElimination.cpp @@ -44,8 +44,14 @@ namespace { virtual bool runOnFunction(Function &F) { bool Changed = false; + + DominatorTree &DT = getAnalysis<DominatorTree>(); + for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) - Changed |= runOnBasicBlock(*I); + // Only check non-dead blocks. Dead blocks may have strange pointer + // cycles that will confuse alias analysis. + if (DT.isReachableFromEntry(I)) + Changed |= runOnBasicBlock(*I); return Changed; } diff --git a/test/Transforms/DeadStoreElimination/crash.ll b/test/Transforms/DeadStoreElimination/crash.ll index f89f8f5185..6d8ba71b20 100644 --- a/test/Transforms/DeadStoreElimination/crash.ll +++ b/test/Transforms/DeadStoreElimination/crash.ll @@ -41,3 +41,17 @@ bb14: ; preds = %bb4 } declare void @llvm.memcpy.i64(i8* nocapture, i8* nocapture, i64, i32) nounwind + + +; rdar://7635088 +define i32 @test3() { +entry: + ret i32 0 + +dead: + %P2 = getelementptr i32 *%P2, i32 52 + %Q2 = getelementptr i32 *%Q2, i32 52 + store i32 4, i32* %P2 + store i32 4, i32* %Q2 + br label %dead +}
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