These documents are a random collection of notes that I have made while working on LLVM. None of them are official, they may be gibberish and not make sense, but they also might be useful. Many of these ideas will find their way into LLVM in some form or another, but nothing is guaranteed. :)
If there is something here that interests you, and you would like to see it in LLVM sooner, rather than later, send an email to the LLVMdev list. We would be happy to help you when/if you run into trouble implementing it.