[PATCH] D127801: [InstCombine] convert mask and shift of power-of-2 to cmp+select

[chenglin.bi via Phabricator via llvm-commits]

bcl5980 added a comment.

Thanks for the x86 counter example that I haven't thought about. 
My point is backend can do this transform also. But it is hard to invert it if we canonicalize IR `shift+and` to `icmp+select`. 
I think we need someone else help to review the discussion @RKSimon @nikic @craig.topper.


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https://reviews.llvm.org/D127801