[all-commits] [llvm/llvm-project] c4763e: [profcheck][InstCombine] Preserve branch weights i...

[Alan Zhao via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c4763e2b9038fbd1154f0276a8b9542b8c115111
      https://github.com/llvm/llvm-project/commit/c4763e2b9038fbd1154f0276a8b9542b8c115111
  Author: Alan Zhao <ayzhao at google.com>
  Date:   2025-11-03 (Mon, 03 Nov 2025)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
    M llvm/test/Transforms/InstCombine/select-safe-transforms.ll
    M llvm/utils/profcheck-xfail.txt

  Log Message:
  -----------
  [profcheck][InstCombine] Preserve branch weights in logical identities (#165810)

For the simplification
```
(C && A) || (!C && B) --> sel C, A, B
```
(and related), if `C` (or (`!C`)) is the condition in the select
instruction representing the logical and, we can preserve that logical
and's branch weights when emitting the new instruction. Otherwise, the
profile data is unknown.

If `C` is the condition of both logical ands, then we just take the
branch weights of the first logical and (though in practice they should
be equal.)

Furthermore, `select-safe-transforms.ii` now passes under the profcheck
configuration, so we remove it from the failing tests.

Tracking issue: #147390



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