[all-commits] [llvm/llvm-project] 7495f9: [AMDGPU] Fix undefined scc register in successor b...

[mssefat via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 7495f92f08d5d621743d26c410e9b27d872af508
      https://github.com/llvm/llvm-project/commit/7495f92f08d5d621743d26c410e9b27d872af508
  Author: mssefat <42645939+mssefat at users.noreply.github.com>
  Date:   2025-04-30 (Wed, 30 Apr 2025)

  Changed paths:
    M llvm/lib/CodeGen/FinalizeISel.cpp
    M llvm/lib/Target/AMDGPU/SIISelLowering.cpp
    A llvm/test/CodeGen/AMDGPU/finalize-isel-kill-scc-vcc.mir
    M llvm/test/CodeGen/AMDGPU/skip-if-dead.ll

  Log Message:
  -----------
  [AMDGPU] Fix undefined scc register in successor block of SI_KILL terminators (#134718)

Fix issue 131298 where an undefined $scc register causes verifier errors
when using SI_KILL_F32_COND_IMM_TERMINATOR instructions. The problem
occurs because the $scc register defined in a comparison before the kill
terminator is used in successor blocks, but was not properly marked as live-in.

This patch:
- Adds code to check if SCC is used in the successor block
- Adds SCC as a live-in to successor blocks
- Handles both explicit and implicit uses of SCC

With this patch the machine verifier no longer reports undefined $scc
errors in following kill terminator instruction.

Fixes #131298

---------

Co-authored-by: Matt Arsenault <arsenm2 at gmail.com>



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