[llvm] [Coroutines][LazyCallGraph] resumes are not really SCC (PR #116285)

[Tyler Nowicki via llvm-commits]

TylerNowicki wrote:

> having thought about this a bit more, I think this use case makes sense and this change is fine. we can use the fact that spurious ref edges are ok (I hope this doesn't come back to bite us)
> 
> we should add more comments explaining this case where the new functions may not necessarily reference each other and that's ok due to spurious ref edges being allowed

Sorry for the delayed response, I am returning to this now. Thank you for your help on this!

I just want to be clear we are on the same page. To recap, I am modifying how new functions are created during the coroutine split pass. I am planning on simplifying the cfg as I clone, meaning there's never actually a point where we have a fully connected RefSCC. To clarify your prior message by "spurious ref edges", you are referring to the _missing_ ref edges between new functions in the RefSCC. And this sounds fine to you. I just want to be clear.

https://github.com/llvm/llvm-project/pull/116285