[all-commits] [llvm/llvm-project] c4aef9: Check subrange liveness at rematerialization

[Stanislav Mekhanoshin via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c4aef9c28170437372c5f9531af118d8d630f552
      https://github.com/llvm/llvm-project/commit/c4aef9c28170437372c5f9531af118d8d630f552
  Author: Stanislav Mekhanoshin <Stanislav.Mekhanoshin at amd.com>
  Date:   2021-12-13 (Mon, 13 Dec 2021)

  Changed paths:
    M llvm/lib/CodeGen/LiveRangeEdit.cpp
    A llvm/test/CodeGen/AMDGPU/remat-dead-subreg.mir

  Log Message:
  -----------
  Check subrange liveness at rematerialization

LiveRangeEdit::allUsesAvailableAt checks that VNI at use is the same
as at the original use slot. However, the VNI can be the same while
a specific subrange needed for use can be dead at the new index.

This patch adds subrange liveness check if there is a subreg use.

Fixes: SWDEV-312810

Differential Revision: https://reviews.llvm.org/D115278