[PATCH] D65336: [InstSimplify] remove quadratic time looping (PR42771)

[Jay Foad via Phabricator via llvm-commits]

foad added a comment.

> There's a test diff here for a degenerate case with llvm.assume that I didn't step through, but I think that's caused because isInstructionTriviallyDead() may not be true for a function call even if that call has no uses.

The old code would visit %cond1, notice the @llvm.assume, record an assumption that %x==3, and then (because of the "When instructions get deleted re-iterate instead" case) *revisit* the %add and find that it can now be simplified using the assumption. I don't know how important it is to preserve this kind of behaviour.


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  https://reviews.llvm.org/D65336/new/

https://reviews.llvm.org/D65336