[all-commits] [llvm/llvm-project] 1443ba: [AMDGPU] Propagate defining src reg for AGPR to AG...

[vangthao95 via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1443ba6163d66743ff9f9d28b0505fca159b824c
      https://github.com/llvm/llvm-project/commit/1443ba6163d66743ff9f9d28b0505fca159b824c
  Author: Vang Thao <Vang.Thao at amd.com>
  Date:   2021-09-23 (Thu, 23 Sep 2021)

  Changed paths:
    M llvm/lib/Target/AMDGPU/GCNPreRAOptimizations.cpp
    A llvm/test/CodeGen/AMDGPU/agpr-to-agpr-copy.mir
    M llvm/test/CodeGen/AMDGPU/llvm.amdgcn.mfma.ll

  Log Message:
  -----------
  [AMDGPU] Propagate defining src reg for AGPR to AGPR Copys

On targets that do not support AGPR to AGPR copying directly, try to find the
defining accvgpr_write and propagate its source vgpr register to the copies
before register allocation so the source vgpr register does not get clobbered.

The postrapseudos pass also attempt to propagate the defining accvgpr_write but
if the register to propagate is clobbered, it will give up and create new
temporary vgpr registers instead.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D108830