> Is this me opening up a Pandora's Box of ignorance here?  Or is LLVM 
> potentially interesting?  (And were someone motivated into perhaps 
> trying to make an LLVM back-end, where would one start to poke around 
> in, say, the GHC codebase to even begin to implement this?  And how 
> insane would they be driven by the process?)

Apologies for the slow reply.  Actually I think this is a pretty cool idea (with 
a disclaimer that I know very nearly nothing about LLVM).  Provided there are no 
serious gotchas, what you need to do is write a new backend for GHC that 
translates Cmm to LLVM.  This should be pretty straightforward: for example, the 
Cmm->C code generator is only 1000 lines of Haskell:

   http://darcs.haskell.org/ghc/compiler/cmm/PprC.hs

I hope LLVM lets you put data next to code, which is what GHC needs for its info 
tables.  Also I hope it lets you fix global registers.