[llvm] [LV] Apply urem folds to preheader (PR #213928)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> If there are hundreds of files that need manually rewriting I'd rather just have a pre-commit PR that regenerates all the CHECK lines instead. This will be of more benefit to everyone I think, since others will hit exactly the same issue at some point.

I agree with this, but in this case, I think UTC was perturbed by the urem variable-name-change (it uses heuristics to keep variable names), and I don't think there is anything to regen and pre-commit for most files, unfortunately.

https://github.com/llvm/llvm-project/pull/213928