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

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> My concern is that we could miscompile this specially crafted code:

Thank you for finding yet another bug! Fixed now by matching the first XOR (I think I had equivalent logic before the rewrite using count_if == 1, but missed it in the rewrite).

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