[all-commits] [llvm/llvm-project] d610a5: RenameIndependentSubregs: Add missing sub-range fo...

[Petar Avramovic via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: d610a513ce10b41c94da9299e926f22d96e873bc
      https://github.com/llvm/llvm-project/commit/d610a513ce10b41c94da9299e926f22d96e873bc
  Author: Petar Avramovic <Petar.Avramovic at amd.com>
  Date:   2024-04-23 (Tue, 23 Apr 2024)

  Changed paths:
    M llvm/lib/CodeGen/RenameIndependentSubregs.cpp
    M llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.amdgcn.intersect_ray.ll
    M llvm/test/CodeGen/AMDGPU/live-interval-bug-in-rename-independent-subregs.mir

  Log Message:
  -----------
  RenameIndependentSubregs: Add missing sub-range for new IMPLICIT_DEFs (#89050)

Existing sub-ranges are correctly updated because new IMPLICIT_DEF is
added, but there is missing sub-range for IMPLICIT_DEF itself.
Because of missing sub-range in live-intervals for IMPLICIT_DEF,
register allocator does not know that IMPLICIT_DEF rewrites its
virtual sub-registers and can end up assigning overlapping physical
registers to them.
This results in deleting instructions that were defined by sub-registers
overwritten by IMPLICIT_DEF as they are now dead.



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