[PATCH] D142293: [InstCombine] Add PHINode operands to worklist on instruction erasure

[Luke Lau via Phabricator via llvm-commits]

luke added a comment.

In D142293#4079311 <https://reviews.llvm.org/D142293#4079311>, @nikic wrote:

> Hm, this feels very hacky. I don't like the idea of adjusting the worklist management for specific patterns.
>
> To suggest a possible alternative, it might be possible to extend isDeadPHICycle(), by making it look through side-effect free instructions, as well as multiple users. This will allow it to remove larger dead phi cycles, so it would not just peel off one phi cycle at a time, but could remove the whole graph at once. (Of course subject to the visitation limit -- with the current one of 16, that would mean we could remove 8 nested phi cycles in one go, which is probably good enough?)

I agree, I'm not a huge fan of this either. That sounds like a better direction: I'll look into it, thanks


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