Marc: Here are a few things that could be inlined productively (I won't write the tests to see whether the functions when called are the standard functions). Brad 1. (exact->inexact x) => (if (##fixnum? x) (##flonum.<-fixnum x) (exact->inexact x)) 2. (vector-ref v i) (and all the [suf][8,16,32]vector-ref's) => (if (and (##vector? v) (##fixnum? i) (##fixnum.<= 0 i) (##fixnum.< i (##vector-length v))) (##vector-ref v i) (vector-ref v i)) 3. (vector-set v i x) (and all the [suf][8,16,32]vector-set's with appropriate checks for the value of x) (if (and (##vector? v) (##fixnum? i) (##fixnum.<= 0 i) (##fixnum.< i (##vector-length v))) (##vector-set v i x) (vector-ref v i x))