Jon Harrop had an article in the F# Journal a while back where he wrote an x86 JIT compiler for a small functional language in about 200 lines of code. It could express Fibonacci programs, and the compiler's performance beat the equivalent F# program on that toy benchmark.

I think the article itself is behind a paywall, but it looks like he put a similar version of the code on Github: https://github.com/jdh30/FSharpCompiler/blob/master/FSharpCo...