[all-commits] [llvm/llvm-project] de727e: [DAG] isGuaranteedNotToBeUndefOrPoison - add ISD::...

[Krzysztof Drewniak via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: de727e5f511816d74178c8bde35d56cc61ebab6a
      https://github.com/llvm/llvm-project/commit/de727e5f511816d74178c8bde35d56cc61ebab6a
  Author: Krzysztof Drewniak <Krzysztof.Drewniak at amd.com>
  Date:   2026-06-05 (Fri, 05 Jun 2026)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    M llvm/test/CodeGen/X86/freeze-vector.ll

  Log Message:
  -----------
  [DAG] isGuaranteedNotToBeUndefOrPoison - add ISD::CONCAT_VECTORS handling (#200932)

Teach isGuaranteedNotToBeUndefOrPoison to distribute fixed-length
demanded element masks across CONCAT_VECTORS operands. This is part of
the series of fixes needed to resolve a SelectionDAG hang by making it
possible to prove certain values don't need to be frozen.

AI note: an LLM generated the code and the test, I've read them

---------

Co-authored-by: OpenAI Codex <codex at openai.com>



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