[llvm] [HashRecognize] Rewrite arePHIsIntertwined (PR #144878)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> Now I think the XOR might be e.g. multiplied by a (runtime) zero

I've added a test showing that the KnownBits propagation works.

> or be one of the branches of a `SelectInst` that is never taken.

The XOR is checked in the condition of the select, not the branches.

https://github.com/llvm/llvm-project/pull/144878