[PATCH] D150105: [AMDGPU] Recompute liveness in SIOptimizeExecMaskingPreRA

[Pierre van Houtryve via Phabricator via llvm-commits]

Pierre-vh created this revision.
Pierre-vh added reviewers: arsenm, foad, critson.
Herald added subscribers: StephenFan, kerbowa, hiraditya, tpr, dstuttard, yaxunl, jvesely, kzhuravl.
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Pierre-vh requested review of this revision.
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Instead of ad-hoc updating liveness, recompute it completely for the affected register.

This does not affect any existing test and fixes an edge case that
caused a "Non-empty but used interval" error in the register allocator
due to how the pass updated liveranges. It created a "isolated" live-through
segment.

Overall this change just seems to be a net positive with no side effect observed. There may be a compile time impact but it's expected to be minimal.

Fixes SWDEV-388279


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D150105

Files:
  llvm/lib/Target/AMDGPU/SIOptimizeExecMaskingPreRA.cpp
  llvm/test/CodeGen/AMDGPU/optimize-exec-mask-pre-ra-non-empty-but-used-interval.mir

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