[PATCH] D117907: [NewGVN] do phi(undef, x) -> x only if x is not poison

[Nikita Popov via Phabricator via llvm-commits]

nikic requested changes to this revision.
nikic added a comment.
This revision now requires changes to proceed.

It looks like the current behavior matches what GVN does: https://llvm.godbolt.org/z/eTYzMjKf7

If an issue affects both GVN and NewGVN, please always fix it in GVN first. Otherwise the fix will remain untested, and this seems like a situation where it can cause a real regression in optimization quality (because we still treat uninit loads as undef, not poison).


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https://reviews.llvm.org/D117907