[llvm] [ConstraintElim] Preserve analyses when IR is unchanged. (PR #128588)

[Antonio Frighetto via llvm-commits]

https://github.com/antoniofrighetto approved this pull request.

LGTM, thanks!

> `opt -S -passes='require<scalar-evolution>,constraint-elimination' -debug-pass-manager` to check that scalar-evolution is preserved with the change

Looks like scalar evolution is currently already in the set of the preserved analyses.

https://github.com/llvm/llvm-project/pull/128588