[all-commits] [llvm/llvm-project] 1bb3a9: [MachineCopyPropagation] More robust isForwardable...

[Jay Foad via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1bb3a9c6428ea460bcdc2d9eed43866a9a5e2fa8
      https://github.com/llvm/llvm-project/commit/1bb3a9c6428ea460bcdc2d9eed43866a9a5e2fa8
  Author: Jay Foad <jay.foad at amd.com>
  Date:   2022-03-21 (Mon, 21 Mar 2022)

  Changed paths:
    M llvm/lib/CodeGen/MachineCopyPropagation.cpp

  Log Message:
  -----------
  [MachineCopyPropagation] More robust isForwardableRegClassCopy

Change the implementation of isForwardableRegClassCopy so that it
does not rely on getMinimalPhysRegClass. Instead, iterate over all
classes looking for any that satisfy a required property.

NFCI on current upstream targets, but this copes better with
downstream AMDGPU changes where some new smaller classes have been
introduced, which was breaking regclass equality tests in the old
code like:
    if (UseDstRC != CrossCopyRC && CopyDstRC == CrossCopyRC)

Differential Revision: https://reviews.llvm.org/D121903