[llvm] [IR] Add support for metadata attachments for Function Arguments (PR #78893)

[Nikita Popov via llvm-commits]

nikic wrote:

> First time contributor to llvm so not sure about the process to add reviewers or if there needs to be some RFC or something like that.

Yes, this change requires an RFC on https://discourse.llvm.org/ (you can use the "IR & Optimizations" category).

Though I'm pretty sure that the feedback on this one is going to be "don't, add a range attribute instead". I don't like the idea of representing some information as parameter attributes and some as parameter metadata.

https://github.com/llvm/llvm-project/pull/78893