Kavon Farvardin
Yes, callbr is part of the discussion on removing proc-point splitting! Soon there will be an announcement about a new working group dedicated to LLVM issues such as this one on this mailing list. Anyone interested is welcome to join our meetings. We're currently gathering our notes together first, but you can have a look here for a preview: https://gitlab.haskell.org/ghc/ghc/wikis/commentary/compiler/LLVM-Backend-Op...
I, for one, would love to see us try using the native stack register for reasons entirely separate from performance. Namely, it would make using existing debugging and performance analysis tools (e.g. perf) much easier. I believe that Andreas Klebinger has also suggested moving return point info tables away from code. It would be interesting to get an estimate of the size of this effect on performance. Cheers, - Ben