[User23]

So this wasn't what I was expecting.

  * (disassemble (lambda () (apply #'+ '(1 2 3 4 5))))
  ; disassembly for (LAMBDA ())
  ; Size: 21 bytes. Origin: #x5345C11B                          ; (LAMBDA ())
  ; 1B:       498B4510         MOV RAX, [R13+16]                ; thread.binding-stack-pointer
  ; 1F:       488945F8         MOV [RBP-8], RAX
  ; 23:       BA1E000000       MOV EDX, 30
  ; 28:       488BE5           MOV RSP, RBP
  ; 2B:       F8               CLC
  ; 2C:       5D               POP RBP
  ; 2D:       C3               RET
  ; 2E:       CC10             INT3 16                          ; Invalid argument count trap
  NIL
  * (disassemble (lambda () (reduce #'+ '(1 2 3 4 5))))
  ; disassembly for (LAMBDA ())
  ; Size: 21 bytes. Origin: #x5345C1AB                          ; (LAMBDA ())
  ; AB:       498B4510         MOV RAX, [R13+16]                ; thread.binding-stack-pointer
  ; AF:       488945F8         MOV [RBP-8], RAX
  ; B3:       BA1E000000       MOV EDX, 30
  ; B8:       488BE5           MOV RSP, RBP
  ; BB:       F8               CLC
  ; BC:       5D               POP RBP
  ; BD:       C3               RET
  ; BE:       CC10             INT3 16                          ; Invalid argument count trap
  NIL

[lispm]

There is some SBCL compiler optimizer at work.