[llvm] [VPlan] Be more careful with CSE in replicate regions. (PR #162110)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon commented:

> Note that this patch only modifies ::isEqual to check for replicating regions and not getHash, as CSE across replicating regions should be uncommon.

Is there some issue with hashing the parent region in the case of replicates? Would be safer to do that?

https://github.com/llvm/llvm-project/pull/162110