I have seen tight functions compiled with SBCL matching and occasionally exceeding the speed of the C version. SBCL is a compiler which produces very good code.

I have seen tight functions compiled with SBCL matching and occasionally exceeding the speed of the C version. SBCL is a compiler which produces very good code. If you add enough type information so that SBCL can infer the types of all operations, you will get performance which compares very well to C.