[PATCH] D102212: [AMDGPU] Add Optimize VGPR LiveRange Pass.

[Ruiling, Song via Phabricator via llvm-commits]

ruiling created this revision.
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This pass aims to optimize VGPR live-range in a typical divergent if-else
control flow. For example:

def(a)
if(cond)

  use(a)
  ... // A

else

  use(a)

As AMDGPU access vgpr with respect to active-mask, we can mark `a` as
dead in region A. For details, please refer to the comments in
implementation file.

The pass is disabled by default, the frontend can enable it through
"-amdgpu-opt-vgpr-liverange=true".


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D102212

Files:
  llvm/lib/Target/AMDGPU/AMDGPU.h
  llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
  llvm/lib/Target/AMDGPU/CMakeLists.txt
  llvm/lib/Target/AMDGPU/SIOptimizeVGPRLiveRange.cpp
  llvm/test/CodeGen/AMDGPU/vgpr-liverange.ll

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