(defparameter v1 '(1 2 3 4))
(defparameter v2 (vector 1 2 3 4))

(declaim (inline xywh-to-points1))
(defun xywh-to-points1 (xywh)
  (let ((x (first xywh))
        (y (second xywh))
        (w (third xywh))
        (h (fourth xywh)))
    `(,x ,y ,(+ x w) ,y ,(+ x w) ,(+ y h) ,x ,(+ y h))))

(declaim (inline xywh-to-points2))
(defun xywh-to-points2 (xywh)
  (let ((x (aref xywh 0))
        (y (aref xywh 1))
        (w (aref xywh 2))
        (h (aref xywh 3)))
    `(,x ,y ,(+ x w) ,y ,(+ x w) ,(+ y h) ,x ,(+ y h))))

(defun test1 ()
  (declare (optimize (speed 3) (safety 0) (debug 0)))
  (loop for j below 100 do
          (loop for i below 10000000 do
                  (xywh-to-points1 v1))))

(defun test2 ()
  (declare (optimize (speed 3) (safety 0) (debug 0)))
  (loop for j below 100 do
          (loop for i below 10000000 do
                  (xywh-to-points2 v2))))
(time (test1))
(time (test2))