LLVM may be better at generating opcodes, but a lot of things are happening between syntax and opcodes, especially type inference, type checking and inlining (including cross module and now cross functors).

Actually, if ocaml "optimized" compiler have shown anything, it's that micro optimizing instructions and register allocation is not as important as once believed. Indeed, for long amongst "sophisticated languages" Ocaml "optimized compiler" was renowned at the same time for the speed of generated code and for the simplicity of its code generation pass, lacking many advanced features found in ghc for instance.