(defun normal-return (v) (1+ v))
(disassemble 'normal-return)
;; =>
;; 0       dup
;; 1       add1
;; 2       return

(defun block-return (v)
  (cl-block 'top
    (cl-return-from 'top v)))
(disassemble 'block-return)
;; =>
;; 0       constant  --cl-block-\(quote\ top\)--
;; 1       pushcatch 1
;; 4       constant  throw
;; 5       constant  --cl-block-\(quote\ top\)--
;; 6       stack-ref 2
;; 7       call      2
;; 8       pophandler
;; 9:1     return
(defun other-cl-return (v) (cl-return v))
;; =>
;; ... same bytecode as in `block-return'.

(defun ret-in-while (v)
  (dotimes (i 10)
    (when (= v 20)
      (cl-return "return-1")))
  "return-2")
(disassemble 'ret-in-while)
;; =>
;; 0       constant  10
;; 1       constant  0
;; 2:1     dup
;; 3       stack-ref 2
;; 4       lss
;; 5       goto-if-nil 3
;; 8       dup
;; 9       stack-ref 3
;; 10      constant  20
;; 11      eqlsign
;; 12      goto-if-nil 2
;; 15      constant  throw
;; 16      constant  --cl-block-nil--
;; 17      constant  "return-1"
;; 18      call      2
;; 19      discard
;; 20:2    discard
;; 21      dup
;; 22      add1
;; 23      stack-set 1
;; 25      goto      1
;; 28:3    discardN  2
;; 30      constant  "return-2"
;; 31      return