[llvm] [HashRecognize] Strip ValueEvolution (PR #148620)

[Piotr Fusik via llvm-commits]

pfusik wrote:

Now this is a major simplification of the analysis. Thank you.

I'm still not happy with `containsUnreachableOrUnhandled` just checking the instruction types and not how they are connected.
Why not pattern-match the whole loop (without looking for `SimpleRecurrence` and `ConditionalRecurrence` first) ?

https://github.com/llvm/llvm-project/pull/148620