[llvm] [Utils][update_mc_test_checks] Support updating round-trip tests. (PR #164425)

[Alexander Richardson via llvm-commits]

arichardson wrote:

> LGTM!
> 
> I would think the ultimate way is to let the update script understand the lit.cfg file and thus it can parse and generate the same run line as llvm-lit does. I think the current approach is also acceptable.

This would be great and I actually started on working on this a while back: importing lit and having lit do all the parsing and substitutions. I should try to resurrect that change. The only downside is that you now need give the script valid build directory to get all the right substitutions, but that should hopefully be an acceptable tradeoff.



https://github.com/llvm/llvm-project/pull/164425