[all-commits] [llvm/llvm-project] 39fbb5: RegisterCoalescer: Fix not setting undef on coales...

[Matt Arsenault via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 39fbb5c3e307ac06c7ca83aca8e3c76ed99b25f3
      https://github.com/llvm/llvm-project/commit/39fbb5c3e307ac06c7ca83aca8e3c76ed99b25f3
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2021-02-03 (Wed, 03 Feb 2021)

  Changed paths:
    M llvm/lib/CodeGen/RegisterCoalescer.cpp
    A llvm/test/CodeGen/AMDGPU/undef-subreg-use-after-coalesce.mir

  Log Message:
  -----------
  RegisterCoalescer: Fix not setting undef on coalesced subregister uses

This was only adding undef to the use if the copy itself had a
subregister index. It did not consider the subrange liveness if the
use had a subreg index to begin with.