[all-commits] [llvm/llvm-project] bfdca1: RegAllocGreedy: Fix nondeterminism in tryLastChanc...

[Matt Arsenault via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bfdca1535c0d6b8ace3de69ec2e448d93a88b97f
      https://github.com/llvm/llvm-project/commit/bfdca1535c0d6b8ace3de69ec2e448d93a88b97f
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2022-07-27 (Wed, 27 Jul 2022)

  Changed paths:
    M llvm/lib/CodeGen/RegAllocGreedy.h

  Log Message:
  -----------
  RegAllocGreedy: Fix nondeterminism in tryLastChanceRecoloring

tryLastChanceRecoloring iterates over the set of LiveInterval pointers
and used that to seed the recoloring stack, which was
nondeterministic. Fixes a future test failing about 20% of the time.

This just takes the order the interfering vreg was encountered. Not
sure if we should try to order this more intelligently.