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(byte-optimize-approx-equal): Use <=, not <.

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(byte-optimize-minus, byte-optimize-plus): Optimize adding
or subtracting 1.
This commit is contained in:
Richard M. Stallman 1997-05-06 03:53:10 +00:00
parent 3ee4159a4e
commit 1fa68f218e
1 changed files with 19 additions and 1 deletions
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20
lisp/emacs-lisp/byte-opt.el
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@ -643,7 +643,7 @@
;; form))
(defun byte-optimize-approx-equal (x y)
(< (* (abs (- x y)) 100) (abs (+ x y))))
(<= (* (abs (- x y)) 100) (abs (+ x y))))
;; Collect all the constants from FORM, after the STARTth arg,
;; and apply FUN to them to make one argument at the end.
@ -694,6 +694,20 @@
;;; (actually, it would be safe if we know the sole arg
;;; is not a marker).
;; ((null (cdr (cdr form))) (nth 1 form))
((and (null (nthcdr 3 form))
(or (memq (nth 1 form) '(1 -1))
(memq (nth 2 form) '(1 -1))))
;; Optiize (+ x 1) into (1+ x) and (+ x -1) into (1- x).
(let ((integer
(if (memq (nth 1 form) '(1 -1))
(nth 1 form)
(nth 2 form)))
(other
(if (memq (nth 1 form) '(1 -1))
(nth 2 form)
(nth 1 form))))
(list (if (eq integer 1) '1+ '1-)
other)))
(t form)))
(defun byte-optimize-minus (form)
@ -705,6 +719,10 @@
;; (- x y ... 0) --> (- x y ...)
(setq form (copy-sequence form))
(setcdr (cdr (cdr form)) (delq 0 (nthcdr 3 form))))
((equal (nthcdr 2 form) '(1))
(setq form (list '1- (nth 1 form))))
((equal (nthcdr 2 form) '(-1))
(setq form (list '1+ (nth 1 form))))
;; If form is (- CONST foo... CONST), merge first and last.
((and (numberp (nth 1 form))
(numberp last))