;;; byte-opt.el --- the optimization passes of the emacs-lisp byte compiler
-;; Copyright (C) 1991, 1994, 2000, 2001, 2002, 2003, 2004,
-;; 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+;; Copyright (C) 1991, 1994, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
+;; 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
;; Author: Jamie Zawinski <jwz@lucid.com>
;; Hallvard Furuseth <hbf@ulrik.uio.no>
;; This file is part of GNU Emacs.
-;; GNU Emacs is free software; you can redistribute it and/or modify
+;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
-;; the Free Software Foundation; either version 3, or (at your option)
-;; any later version.
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-;; Boston, MA 02110-1301, USA.
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
form))
((or (byte-code-function-p fn)
(eq 'lambda (car-safe fn)))
- (byte-optimize-form-code-walker
- (byte-compile-unfold-lambda form)
- for-effect))
+ (let ((newform (byte-compile-unfold-lambda form)))
+ (if (eq newform form)
+ ;; Some error occurred, avoid infinite recursion
+ form
+ (byte-optimize-form-code-walker newform for-effect))))
((memq fn '(let let*))
;; recursively enter the optimizer for the bindings and body
;; of a let or let*. This for depth-firstness: forms that
(list (apply fun (nreverse constants)))))))))
form))
+(defsubst byte-compile-butlast (form)
+ (nreverse (cdr (reverse form))))
+
(defun byte-optimize-plus (form)
- (setq form (byte-optimize-delay-constants-math form 1 '+))
+ ;; Don't call `byte-optimize-delay-constants-math' (bug#1334).
+ ;;(setq form (byte-optimize-delay-constants-math form 1 '+))
(if (memq 0 form) (setq form (delq 0 (copy-sequence form))))
- ;;(setq form (byte-optimize-associative-two-args-math form))
- (cond ((null (cdr form))
- (condition-case ()
- (eval form)
- (error 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))
- ((null (cddr form))
- (if (numberp (nth 1 form))
- (nth 1 form)
- form))
- ((and (null (nthcdr 3 form))
- (or (memq (nth 1 form) '(1 -1))
- (memq (nth 2 form) '(1 -1))))
- ;; Optimize (+ 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)))
+ ;; For (+ constants...), byte-optimize-predicate does the work.
+ (when (memq nil (mapcar 'numberp (cdr form)))
+ (cond
+ ;; (+ x 1) --> (1+ x) and (+ x -1) --> (1- x).
+ ((and (= (length form) 3)
+ (or (memq (nth 1 form) '(1 -1))
+ (memq (nth 2 form) '(1 -1))))
+ (let (integer other)
+ (if (memq (nth 1 form) '(1 -1))
+ (setq integer (nth 1 form) other (nth 2 form))
+ (setq integer (nth 2 form) other (nth 1 form)))
+ (setq form
+ (list (if (eq integer 1) '1+ '1-) other))))
+ ;; Here, we could also do
+ ;; (+ x y ... 1) --> (1+ (+ x y ...))
+ ;; (+ x y ... -1) --> (1- (+ x y ...))
+ ;; The resulting bytecode is smaller, but is it faster? -- cyd
+ ))
+ (byte-optimize-predicate form))
(defun byte-optimize-minus (form)
- ;; Put constants at the end, except the last constant.
- (setq form (byte-optimize-delay-constants-math form 2 '+))
- ;; Now only first and last element can be a number.
- (let ((last (car (reverse (nthcdr 3 form)))))
- (cond ((eq 0 last)
- ;; (- 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))
- (setq form (nconc (list '- (- (nth 1 form) last) (nth 2 form))
- (delq last (copy-sequence (nthcdr 3 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).
-;;; (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))
-;;; )
- )
+ ;; Don't call `byte-optimize-delay-constants-math' (bug#1334).
+ ;;(setq form (byte-optimize-delay-constants-math form 2 '+))
+ ;; Remove zeros.
+ (when (and (nthcdr 3 form)
+ (memq 0 (cddr form)))
+ (setq form (nconc (list (car form) (cadr form))
+ (delq 0 (copy-sequence (cddr form)))))
+ ;; After the above, we must turn (- x) back into (- x 0)
+ (or (cddr form)
+ (setq form (nconc form (list 0)))))
+ ;; For (- constants..), byte-optimize-predicate does the work.
+ (when (memq nil (mapcar 'numberp (cdr form)))
+ (cond
+ ;; (- x 1) --> (1- x)
+ ((equal (nthcdr 2 form) '(1))
+ (setq form (list '1- (nth 1 form))))
+ ;; (- x -1) --> (1+ x)
+ ((equal (nthcdr 2 form) '(-1))
+ (setq form (list '1+ (nth 1 form))))
+ ;; (- 0 x) --> (- x)
+ ((and (eq (nth 1 form) 0)
+ (= (length form) 3))
+ (setq form (list '- (nth 2 form))))
+ ;; Here, we could also do
+ ;; (- x y ... 1) --> (1- (- x y ...))
+ ;; (- x y ... -1) --> (1+ (- x y ...))
+ ;; The resulting bytecode is smaller, but is it faster? -- cyd
+ ))
+ (byte-optimize-predicate 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)
-;;; 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) (cons 'progn (cdr form)))
- ((eq 1 last) (delq 1 (copy-sequence form)))
- ((eq -1 last) (list '- (delq -1 (copy-sequence form))))
- ((and (eq 2 last)
- (memq t (mapcar 'symbolp (cdr form))))
- (prog1 (setq form (delq 2 (copy-sequence form)))
- (while (not (symbolp (car (setq form (cdr form))))))
- (setcar form (list '+ (car form) (car form)))))
- (form))))))
-
-(defsubst byte-compile-butlast (form)
- (nreverse (cdr (reverse form))))
+ ;; For (* constants..), byte-optimize-predicate does the work.
+ (when (memq nil (mapcar 'numberp (cdr form)))
+ ;; After `byte-optimize-predicate', if there is a INTEGER constant
+ ;; in FORM, it is in the last element.
+ (let ((last (car (reverse (cdr form)))))
+ (cond
+ ;; Would handling (* ... 0) here cause floating point errors?
+ ;; See bug#1334.
+ ((eq 1 last) (setq form (byte-compile-butlast form)))
+ ((eq -1 last)
+ (setq form (list '- (if (nthcdr 3 form)
+ (byte-compile-butlast form)
+ (nth 1 form))))))))
+ (byte-optimize-predicate form))
(defun byte-optimize-divide (form)
(setq form (byte-optimize-delay-constants-math form 2 '*))
+ ;; After `byte-optimize-predicate', if there is a INTEGER constant
+ ;; in FORM, it is in the last element.
(let ((last (car (reverse (cdr (cdr form))))))
- (if (numberp last)
- (cond ((= (length form) 3)
- (if (and (numberp (nth 1 form))
- (not (zerop last))
- (condition-case nil
- (/ (nth 1 form) last)
- (error nil)))
- (setq form (list 'progn (/ (nth 1 form) last)))))
- ((= last 1)
- (setq form (byte-compile-butlast form)))
- ((numberp (nth 1 form))
- (setq form (cons (car form)
- (cons (/ (nth 1 form) last)
- (byte-compile-butlast (cdr (cdr form)))))
- last nil))))
(cond
-;;; ((null (cdr (cdr form)))
-;;; (nth 1 form))
- ((eq (nth 1 form) 0)
- (append '(progn) (cdr (cdr form)) '(0)))
- ((eq last -1)
- (list '- (if (nthcdr 3 form)
- (byte-compile-butlast form)
- (nth 1 form))))
- (form))))
+ ;; Runtime error (leave it intact).
+ ((or (null last)
+ (eq last 0)
+ (memql 0.0 (cddr form))))
+ ;; No constants in expression
+ ((not (numberp last)))
+ ;; For (* constants..), byte-optimize-predicate does the work.
+ ((null (memq nil (mapcar 'numberp (cdr form)))))
+ ;; (/ x y.. 1) --> (/ x y..)
+ ((and (eq last 1) (nthcdr 3 form))
+ (setq form (byte-compile-butlast form)))
+ ;; (/ x -1), (/ x .. -1) --> (- x), (- (/ x ..))
+ ((eq last -1)
+ (setq form (list '- (if (nthcdr 3 form)
+ (byte-compile-butlast form)
+ (nth 1 form)))))))
+ (byte-optimize-predicate form))
(defun byte-optimize-logmumble (form)
(setq form (byte-optimize-delay-constants-math form 1 (car form)))
char-equal char-to-string char-width
compare-strings concat coordinates-in-window-p
copy-alist copy-sequence copy-marker cos count-lines
- decdoe-char
+ decode-char
decode-time default-boundp default-value documentation downcase
elt encode-char exp expt encode-time error-message-string
fboundp fceiling featurep ffloor
next-window nth nthcdr number-to-string
parse-colon-path plist-get plist-member
prefix-numeric-value previous-window prin1-to-string propertize
+ degrees-to-radians
radians-to-degrees rassq rassoc read-from-string regexp-quote
region-beginning region-end reverse round
sin sqrt string string< string= string-equal string-lessp string-to-char
HCoop / bpt / emacs.git / blobdiff