[all-commits] [llvm/llvm-project] 0c8e57: [AMDGPU] Insert exec-forced V_NOP after V_PERM_PK1...

[hidekisaito via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0c8e5777423c2e657d7e5c61b2cc812253f9b3ec
      https://github.com/llvm/llvm-project/commit/0c8e5777423c2e657d7e5c61b2cc812253f9b3ec
  Author: hidekisaito <hidekido at amd.com>
  Date:   2026-09-29 (Tue, 29 Sep 2026)

  Changed paths:
    M llvm/lib/Target/AMDGPU/AMDGPU.td
    M llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
    M llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
    M llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
    M llvm/lib/Target/AMDGPU/SIInstrInfo.h
    M llvm/test/CodeGen/AMDGPU/llvm.amdgcn.perm.pk.ll
    A llvm/test/CodeGen/AMDGPU/remove-short-exec-branches-vperm-pk16.mir
    A llvm/test/CodeGen/AMDGPU/vperm-pk16-exec-hazard.ll
    A llvm/test/CodeGen/AMDGPU/vperm-pk16-exec-hazard.mir

  Log Message:
  -----------
  [AMDGPU] Insert exec-forced V_NOP after V_PERM_PK16 (gfx1250/gfx1251 hazard) (#214406)

On gfx1250/gfx1251 the V_PERM_PK16 family (V_PERM_PK16_B4/B6/B8_U4) has
a hazard: the instruction must be immediately followed by a "safe"
instruction that issues on the pipe which clears the hazard. Insert
V_NOP as needed.

Also updated hasUnwantedEffectsWhenEXECEmpty() to ensure V_PERM_PK16 and
the inserted V_NOP are under non-zero EXEC.

Fixes: ROCM-26041

Assisted-by: Opus 4.8 Medium



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