CL-USER> (declaim (optimize (speed 3)))
NIL
CL-USER> (defun f () 7)
(disassemble 'f)
WARNING: redefining COMMON-LISP-USER::F in DEFUN
; disassembly for F
; Size: 24 bytes. Origin: #x7005431E8C                        ; F
; 8C:       CA0180D2         MOVZ R0, #14
; 90:       FB031AAA         MOV CSP, CFP
; 94:       5A7B40A9         LDP CFP, LR, [CFP]
; 98:       BF0300F1         CMP NULL, #0
; 9C:       C0035FD6         RET
; A0:       E00120D4         BRK #15                          ; Invalid argument count trap
NIL


CL-USER> (declaim (optimize (speed 0)))
NIL
CL-USER> (defun f () 7)
(disassemble 'f)
WARNING: redefining COMMON-LISP-USER::F in DEFUN
; disassembly for F
; Size: 32 bytes. Origin: #x7005431F1C                        ; F
; 1C:       AA0A40F9         LDR R0, [THREAD, #16]            ; binding-stack-pointer
; 20:       4A0B00F9         STR R0, [CFP, #16]
; 24:       CA0180D2         MOVZ R0, #14
; 28:       FB031AAA         MOV CSP, CFP
; 2C:       5A7B40A9         LDP CFP, LR, [CFP]
; 30:       BF0300F1         CMP NULL, #0
; 34:       C0035FD6         RET
; 38:       E00120D4         BRK #15                          ; Invalid argument count trap