[llvm] [SCEV] Try to fold ZExt/SExt of AddRec before existing lookup. (PR #208805)

[Ramkumar Ramachandra via llvm-commits]

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artagnon wrote:

Hm, getting improvements by moving the code before the UniqueSCEVs lookup indicates that there's an underlying problem with what we insert into UniqueSCEVs in the first place?

https://github.com/llvm/llvm-project/pull/208805