[PATCH] D62818: [InstCombine] Allow ((X << Y) & SignMask) != 0 to be optimized as (X << Y) s< 0.

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

So we're missing an undo fold: https://rise4fun.com/Alive/w25
Not sure if it should be guarded by a TTI hook, i would expect it to be always beneficial.
(that doesn't mind the original fold is always not beneficial though)
I'll try to take a look.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D62818/new/

https://reviews.llvm.org/D62818