dynamic-extent form takes a very long time to compile

[Paul F. Dietz]

(defun dxf (x i) (elt x i))
(declaim (notinline dxf))

(defun f350 (a b)
  (let ((v
         (vector
          (vector
           (unwind-protect 1)
           2)
          (max 36028797018963969 -2627932703771407
               (if b 0 1)
               (if b 2 3)
               a
               (if b 4 5)
               ; 1 2 3
               (if b 6 7)
               a
               (if b 8 9)
               (if b 10 11)
               (if b 12 13)
               (if b 14 15)
               a
               ))))
    (declare (dynamic-extent v))
    (dxf v 1)))

The large defun there took nearly an hour to compile. Tweaking it by adding or removing arguments in the MAX form, there seems to be an exponential behavior in the algorithm.

[Stas Boukarev (stassats)]

9105ecaa6a40fcb1997de68084d3dfacf59074bb