[all-commits] [llvm/llvm-project] 468ff7: [X86] combineVectorHADDSUB - remove the broken HOP...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 468ff703e114599ce8fb7457bd3c7ef0b219e952
      https://github.com/llvm/llvm-project/commit/468ff703e114599ce8fb7457bd3c7ef0b219e952
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-09-27 (Mon, 27 Sep 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/horizontal-shuffle-2.ll

  Log Message:
  -----------
  [X86] combineVectorHADDSUB - remove the broken HOP(x,x) merging code (PR51974)

This intention of this code turns out to be superfluous as we can handle this with shuffle combining, and it has a critical flaw in that it doesn't check for dependencies.

Fixes PR51974