[llvm] [ConstraintElimination] Handle equality predicates with signed system (PR #205331)

[Florian Hahn via llvm-commits]

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

> Constraining this by checking whether at least one operand exists in the signed system seems to somewhat alleviate the regressions: https://llvm-compile-time-tracker.com/compare.php?from=2c57ae5efb0159521287c80255e3a604f3b0dcfe&to=bf39b0cddfedee71eeb90ba44abc16509b9ffce3&stat=instructions:u.

Ah right, I thought we were already doing that. Good to see that this is quite a bit better now, thanks.

LGTM

https://github.com/llvm/llvm-project/pull/205331