There is Gambit Scheme, MIT Scheme, PLT Scheme, Chicken Scheme, Bigloo, Larceny, ...; then there are all the lisps.

Yet, there's not (to my knowledge) a single popular scheme/lisp on LLVM, even though LLVM provides lots of nice things like:

easier to generate code than x86

easy to make C FFI calls ...

So why is it that there isn't a good scheme/lisp on LLVM?