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

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> > The challenge with mass test updates is always reverting unwanted hunks :( If you use Magit or some other git frontend, it should make it easier?
> 
> Sorry, I don't know what you mean. How can I revert test changes if that would cause the tests to fail?

Ah, the trick is always selecting the hunks in the diff to stage -- Magit is just a nicer frontend to `git add -p`, so you stage just the urem change in each file, and drop the rest? When the FileCheck pattern is different, you'd have to manually edit and rewrite it to the earlier pattern though, and I know the pain myself :(

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