[clang] [llvm] [IR] Add getelementptr nusw and nuw flags (PR #90824)

[Nikita Popov via cfe-commits]

nikic wrote:

> Are the TODOs encompassing all the cases? Why we don't want to set the flags in `PHITransAddr` as well?

No, the TODOs are only for places where I had to modify code, but the used implementation is obviously non-optimal to minimize initial impact. There are many more places that need to be modified to full propagate the flags everywhere.

https://github.com/llvm/llvm-project/pull/90824