[PATCH] D65147: [SimplifyCFG] FoldTwoEntryPHINode(): don't bailout on i1 PHI's if we can hoist a 'not' from incoming values

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D65147#1608214 <https://reviews.llvm.org/D65147#1608214>, @spatel wrote:

> This looks like a safe easing of the heuristic, so LGTM.


Thank you for the review.

> It would be nice if we could lift "IsFreeToInvert()" from InstCombine to some common location and reuse that here as a follow-up. That function goes further than what is proposed here, and I'm not sure how the extra clauses will interact with SimplifyCFG, so that requires some extra tests to see if it behaving as intended in relation this heuristic.

Yeah, they do similar things, but indeed it isn't obvious if it would be a good fit here.


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