In general I would be very curious to know more about the bugs, etc in LLVM which would benefit Rust. I'm of the impression that there are many because LLVM is so over-fitted to the C++ ecosystem, but I don't know much about them in particular.
If you're looking for someone to ask, the expert is nikic, author of the grandparent to your comment. They have worked on many of these specific improvements in LLVM, from which Rust has benefited.
You're saying the person complaining about the release notes is one of the people who wrote the release notes? :-D
The `A-LLVM` issue label is probably a good starting point.