[all-commits] [llvm/llvm-project] 5dbb53: [InstCombine] merge shuffled vector negate and mul...

[Sanjay Patel via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 5dbb53b1b4e07a0029569d394cf007a30a0882de
      https://github.com/llvm/llvm-project/commit/5dbb53b1b4e07a0029569d394cf007a30a0882de
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2022-03-24 (Thu, 24 Mar 2022)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
    M llvm/test/Transforms/InstCombine/shuffle_select.ll

  Log Message:
  -----------
  [InstCombine] merge shuffled vector negate and multiply

Add the "(0 - X) --> (X * -1)" reverse identity to the list of alternate form binops.

We need a little hack to make the existing logic work because it does not expect to
move constants from op0 to op1, but the code comment hopefully makes that clear.
I don't think there are any other identities like that.

Fixes #54364

Differential Revision: https://reviews.llvm.org/D122390