[all-commits] [llvm/llvm-project] 51d33a: [RegisterCoalescer] Fix crash on early clobbered s...

[Daniil Fukalov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 51d33afcbe0a81bb8508d5685f38dc9fdb2b60c9
      https://github.com/llvm/llvm-project/commit/51d33afcbe0a81bb8508d5685f38dc9fdb2b60c9
  Author: Daniil Fukalov <1671137+dfukalov at users.noreply.github.com>
  Date:   2022-09-06 (Tue, 06 Sep 2022)

  Changed paths:
    M llvm/lib/CodeGen/RegisterCoalescer.cpp
    A llvm/test/CodeGen/AMDGPU/coalescer-early-clobber-subreg.mir

  Log Message:
  -----------
  [RegisterCoalescer] Fix crash on early clobbered subreg operands.

The issue was with processing two subregs of the same reg are used in the same
instruction (e.g. inline asm): "def early-clobber" and other just "def".
Register coalescer ran in bad recursion if the early clobbered subreg is second
in the following sequence of COPYs.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D127136