[all-commits] [llvm/llvm-project] 149ed9: AMDGPU: update GFX11 wmma hazards (#76143)

[Petar Avramovic via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 149ed9d2c58095f87745f8696ef96b5076c91fca
      https://github.com/llvm/llvm-project/commit/149ed9d2c58095f87745f8696ef96b5076c91fca
  Author: Petar Avramovic <Petar.Avramovic at amd.com>
  Date:   2024-01-24 (Wed, 24 Jan 2024)

  Changed paths:
    M llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
    M llvm/test/CodeGen/AMDGPU/wmma-hazards.mir

  Log Message:
  -----------
  AMDGPU: update GFX11 wmma hazards (#76143)

One V_NOP or unrelated VALU instruction in between is required for
correctness when matrix A or B of current WMMA instruction overlaps with
matrix D of previous WMMA instruction.
Remaining cases of WMMA operand overlaps are handled by the hardware and
do not require handling in hazard recognizer.

Hardware may stall in cases where:
- matrix C of current WMMA instruction overlaps with matrix D of
previous WMMA instruction
- VALU instruction reads matrix D of previous WMMA instruction
- matrix A,B or C of WMMA instruction reads result of previous VALU
instruction