[PATCH] D152744: [DSE] Don't eagerly optimize MemorySSA uses

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added a comment.

With optimized uses, here <https://github.com/llvm/llvm-project/blob/34d7acd444b88342fc93fca202608c1e16fa5946/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp#L1422> in some cases we'd see more uses of a MemoryUse and this <https://github.com/llvm/llvm-project/blob/34d7acd444b88342fc93fca202608c1e16fa5946/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp#L1282> would imprecisely return `Ref` instead of `NoModRef`. I think it's because this <https://github.com/llvm/llvm-project/blob/1d6c3e29f6aa45914faa7be00a939b8f550f38e9/llvm/lib/Analysis/MemorySSA.cpp#L379> bypasses the logic in D152743 <https://reviews.llvm.org/D152743>, but I didn't double check that

example <https://github.com/llvm/llvm-project/blob/d167fe0c4ed6983b56c6b0209eb2a2b4cc1d3e0e/llvm/test/Analysis/TypeBasedAliasAnalysis/dse.ll#L41> where this happened


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https://reviews.llvm.org/D152744