[all-commits] [llvm/llvm-project] 16b2ef: [CodeGen] Debug insns must not affect liveness ana...

[LU-JOHN via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 16b2ef32bef0e0f32ca89eca338d20b63df335d1
      https://github.com/llvm/llvm-project/commit/16b2ef32bef0e0f32ca89eca338d20b63df335d1
  Author: LU-JOHN <John.Lu at amd.com>
  Date:   2026-05-14 (Thu, 14 May 2026)

  Changed paths:
    M llvm/include/llvm/CodeGen/MachineOutliner.h
    M llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
    M llvm/lib/CodeGen/LiveRegUnits.cpp
    M llvm/lib/CodeGen/RegisterScavenging.cpp
    M llvm/lib/CodeGen/RemoveLoadsIntoFakeUses.cpp
    M llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
    M llvm/lib/Target/SystemZ/SystemZShortenInst.cpp
    M llvm/lib/Target/X86/X86FixupBWInsts.cpp
    M llvm/test/CodeGen/AArch64/machine-outliner-calls.mir
    A llvm/test/CodeGen/AMDGPU/debug-independence-dead-mi-elimination.mir
    M llvm/test/CodeGen/AMDGPU/eliminate-frame-index-v-add-co-u32.mir
    M llvm/test/CodeGen/ARM/flag-crash.ll
    M llvm/test/CodeGen/Thumb2/ldr-str-imm12.ll
    M llvm/test/CodeGen/WebAssembly/simd-arith.ll

  Log Message:
  -----------
  [CodeGen] Debug insns must not affect liveness analysis (#193104)

Register references in debug instructions can affect LiveRegUnits
analysis. Skip over debug instructions.

Tests in this PR would fail due to calls to LiveRegUnits::stepBackward
in RegisterScavenging, DeadMachineInstructionElim, and
AArch64InstrInfo.cpp getOutlinableRanges().

Other call-sites to stepBackward may also pass debug instructions to
LiveRegUnits::stepBackward, but LIT testing did not fail when
-debugify-and-strip-all-safe was enabled by default.

---------

Signed-off-by: John Lu <John.Lu at amd.com>



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