[all-commits] [llvm/llvm-project] dd5af8: [AMDGPU] Mark S_NOP as having side effects (#65745)

[Jay Foad via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: dd5af895bb7233471256bb8bfb013d49a71973f0
      https://github.com/llvm/llvm-project/commit/dd5af895bb7233471256bb8bfb013d49a71973f0
  Author: Jay Foad <jay.foad at amd.com>
  Date:   2023-09-08 (Fri, 08 Sep 2023)

  Changed paths:
    M llvm/lib/Target/AMDGPU/SOPInstructions.td
    M llvm/test/CodeGen/AMDGPU/copy-vgpr-clobber-spill-vgpr.mir
    M llvm/test/CodeGen/AMDGPU/fold-immediate-operand-shrink.mir
    M llvm/test/CodeGen/AMDGPU/sched-barrier-pre-RA.mir
    M llvm/test/CodeGen/AMDGPU/sched-group-barrier-pipeline-solver.mir
    M llvm/test/CodeGen/AMDGPU/sched-group-barrier-pre-RA.mir
    M llvm/test/CodeGen/AMDGPU/spill-empty-live-interval.mir

  Log Message:
  -----------
  [AMDGPU] Mark S_NOP as having side effects (#65745)

This prevents S_NOP from being rescheduled past other (side-effecting)
instructions, which is useful because it is generally used to introduce
a short delay or to avoid hazards. Currently this only affects MIR tests
because the compiler itself only inserts nops in PostRAHazardRecognizer
which runs after all scheduling.