[llvm] [ConstraintElim] Check the other signedness when hasSameSign (PR #128168)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon commented:

Looks reasonable, but I think the test coverage is lacking: how about a dominating samesign condition as well?

https://github.com/llvm/llvm-project/pull/128168