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

[Ramkumar Ramachandra via llvm-commits]

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artagnon wrote:

I think it would be cleaner to handle PredPHI here, as I think getOpcodeOrIntrinsicID can be shared?

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