[PATCH] D157290: [InstCombine] Fold (-a >> b) and/or/xor (~a >> b) into (-a and/or/xor ~a) >> b

Maksim Kita via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Sat Aug 12 11:37:31 PDT 2023


kitaisreal added a comment.

In D157290#4582227 <https://reviews.llvm.org/D157290#4582227>, @nikic wrote:

> As far as I can tell the `sub 0, x` is irrelevant for the transform. Can you please remove it from the proofs (and tests)?

Yes, `sub 0, x` is irrelevant for the transform. I need to use some instruction to transform `x` so that whole expression will not be optimized by other transformations. I updated tests to use `mul`, it seems from other tests `mul` and `div` are usually used for this.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157290/new/

https://reviews.llvm.org/D157290



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