(if ('#<procedure #2 ##fx<> i 0)
(let ((begin-temp.1 ('#<procedure #3 ##u8vector-set!> out i ('#<procedure #4 ##u8vector-ref> in i))))
(do-temp.0 in out ('#<procedure #5 ##fx-> i 1)))))))
(let ((i ('#<procedure #5 ##fx-> ('#<procedure #6 ##u8vector-length> in) 1)))
(if ('#<procedure #2 ##fx<> i 0)
(let ((begin-temp.1 ('#<procedure #3 ##u8vector-set!> out i ('#<procedure #4 ##u8vector-ref> in i))))
(do-temp.0 in out ('#<procedure #5 ##fx-> i 1))))))))
which seems to have about 1 extra instruction (I don't know what the load effective address is doing there).