[llvm] [LoopUtils] Fix exit value rewriting for repeated PHI predecessors (PR #222177)

[via llvm-commits]

Vladexy88x wrote:

I took some time to review and test this PR locally

>From my testing and reading of the code, the fix looks correct and well-targeted. I reproduced the failure without the fix and verified that the malformed PHI is no longer produced with the fix applied. I also ran the relevant IndVarSimplify and LoopStrengthReduce tests without finding any regressions

I'm not a maintainer, so this is just my independent review, but from what I can see, the change is well done and I didn't find any issues with it

https://github.com/llvm/llvm-project/pull/222177