[all-commits] [llvm/llvm-project] 00b469: [CodeGenPrepare] Use recomputed split-branch weigh...

[Justin Lebar via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 00b4695f1dc6b04168be2e1ed8368624d768314f
      https://github.com/llvm/llvm-project/commit/00b4695f1dc6b04168be2e1ed8368624d768314f
  Author: Justin Lebar <justin.lebar at gmail.com>
  Date:   2026-05-27 (Wed, 27 May 2026)

  Changed paths:
    M llvm/lib/CodeGen/CodeGenPrepare.cpp
    M llvm/test/CodeGen/AArch64/fast-isel-branch-cond-split.ll
    A llvm/test/Transforms/CodeGenPrepare/X86/split-branch-cond-weights.ll

  Log Message:
  -----------
  [CodeGenPrepare] Use recomputed split-branch weights. (#199822)

splitBranchCondition computes new branch weights after splitting an
and/or condition into two branches, but then passed the original weights
to createBranchWeights at each metadata update. The recomputed values
were discarded.

Pass the scaled NewTrueWeight/NewFalseWeight values when installing
metadata on both generated branches.

This bug was found by a large run of Opus 4.7 looking for bugs in LLVM.



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