[all-commits] [llvm/llvm-project] 866a73: TwoAddressInstruction: Don't repair the unchanged ...

[Matt Arsenault via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 866a738a0357106ce668543eeeb8314c0a0efeed
      https://github.com/llvm/llvm-project/commit/866a738a0357106ce668543eeeb8314c0a0efeed
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2026-09-08 (Tue, 08 Sep 2026)

  Changed paths:
    M llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
    A llvm/test/CodeGen/AMDGPU/early-lis-two-address-regsequence-undef.mir

  Log Message:
  -----------
  TwoAddressInstruction: Don't repair the unchanged def of a degenerate REG_SEQUENCE (#222053)

When every source operand of a REG_SEQUENCE is undef,
eliminateRegSequence rewrites the instruction in place to IMPLICIT_DEF. 
The dead def of DstReg is left untouched, so its live range is already correct. 
Passing DstReg to repairIntervalsInRange then makes it re-add an overlapping 
segment with a fresh value for the unchanged def, asserting in 
LiveInterval::addSegment. Drop DstReg from the repaired set in this case. 
Exposed by -early-live-intervals

Co-authored-by: Claude (Claude-Opus-4.8)



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