[all-commits] [llvm/llvm-project] ed866d: [X86][Combine] Ensure single use chain in extract-...

[Evgenii Kudriashov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ed866d994c3b074cb1b7a380b1ce9169dde3362c
      https://github.com/llvm/llvm-project/commit/ed866d994c3b074cb1b7a380b1ce9169dde3362c
  Author: Evgenii Kudriashov <evgenii.kudriashov at intel.com>
  Date:   2025-04-24 (Thu, 24 Apr 2025)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/extractelement-load.ll

  Log Message:
  -----------
  [X86][Combine] Ensure single use chain in extract-load combine (#136520)

The problem is that `SrcBC = peekThroughBitcasts(Src)` doesn't ensure
single use chain. It results in the situation when a cast may have
multiple users and instead of replacing a load we introduce a new one.
The situation is worsened by the fact that we've replaced the token from
the original load and its correct memory order now is not guaranteed.



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