[llvm] [ConstraintElim] Add (UGE, var, 0) to unsigned system for new vars. (PR #76262)

[Nikita Popov via llvm-commits]

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

LGTM. I think the compile-time cost is justified in this case.

This significantly increases the constraint system size, so we're more likely to hit cutoffs, but that's probably less important.

https://github.com/llvm/llvm-project/pull/76262