[llvm] [ConstraintElim] Use cond from header as upper bound on IV in exit BB. (PR #94610)

[Nikita Popov via llvm-commits]

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

LGTM if no compile-time impact.

Please double-check whether this actually fixes https://github.com/llvm/llvm-project/issues/90417 (with current phase ordering) and drop the line from the PR description if not.

https://github.com/llvm/llvm-project/pull/94610