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Richard M. Stallman 1992-07-31 02:30:04 +00:00
parent 643f763f7d
commit 3315a6a3a4
1 changed files with 19 additions and 7 deletions
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26
lisp/emacs-lisp/byte-opt.el
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@ -604,7 +604,10 @@
(condition-case ()
(eval form)
(error form)))
((null (cdr (cdr form))) (nth 1 form))
;;; It is not safe to delete the function entirely
;;; (actually, it would be safe if we know the sole arg
;;; is not a marker).
;; ((null (cdr (cdr form))) (nth 1 form))
(t form)))
(defun byte-optimize-minus (form)
@ -621,19 +624,27 @@
(numberp last))
(setq form (nconc (list '- (- (nth 1 form) last) (nth 2 form))
(delq last (copy-sequence (nthcdr 3 form))))))))
(if (eq (nth 2 form) 0)
(nth 1 form) ; (- x 0) --> x
;;; It is not safe to delete the function entirely
;;; (actually, it would be safe if we know the sole arg
;;; is not a marker).
;;; (if (eq (nth 2 form) 0)
;;; (nth 1 form) ; (- x 0) --> x
(byte-optimize-predicate
(if (and (null (cdr (cdr (cdr form))))
(eq (nth 1 form) 0)) ; (- 0 x) --> (- x)
(cons (car form) (cdr (cdr form)))
form))))
form))
;;; )
)
(defun byte-optimize-multiply (form)
(setq form (byte-optimize-delay-constants-math form 1 '*))
;; If there is a constant in FORM, it is now the last element.
(cond ((null (cdr form)) 1)
((null (cdr (cdr form))) (nth 1 form))
;;; It is not safe to delete the function entirely
;;; (actually, it would be safe if we know the sole arg
;;; is not a marker or if it appears in other arithmetic).
;;; ((null (cdr (cdr form))) (nth 1 form))
((let ((last (car (reverse form))))
(cond ((eq 0 last) (list 'progn (cdr form)))
((eq 1 last) (delq 1 (copy-sequence form)))
@ -659,8 +670,9 @@
(cons (/ (nth 1 form) last)
(byte-compile-butlast (cdr (cdr form)))))
last nil))))
(cond ((null (cdr (cdr form)))
(nth 1 form))
(cond
;;; ((null (cdr (cdr form)))
;;; (nth 1 form))
((eq (nth 1 form) 0)
(append '(progn) (cdr (cdr form)) '(0)))
((eq last -1)