There’s a Haskell (GHC) backend targeting the LLVM.
You could also try using F# through Mono-LLVM.
Also, the VMKit project is implementing both the JVM and the .NET CLI on top of LLVM; it’s still in its early stages but once it matures you could use it with F#, or any JVM-targeting functional languages (Scala, Clojure, etc.)