X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=lisp%2Fbyte-optimize.el;h=c84fd233718771a7b25d43e2c09ea74cd0e20eb9;hb=3ca93f4c76fca3afcbe47893ef6ac97b12a9c30b;hp=f591e82d5c6710e6aa800aee828cb8932e001ff1;hpb=0c693dc08f0794304711787b2eb47c144ea4bef1;p=chise%2Fxemacs-chise.git-

diff --git a/lisp/byte-optimize.el b/lisp/byte-optimize.el
index f591e82..c84fd23 100644
--- a/lisp/byte-optimize.el
+++ b/lisp/byte-optimize.el
@@ -704,7 +704,7 @@
 ;;; is not a marker or if it appears in other arithmetic).
 
 ;;; But this degree of paranoia is normally unjustified, so optimize unless
-;;; the user has done (declaim (safety 3)).  Implemented in bytecomp.el.
+;;; the user has done (declaim (optimize (safety 3))).  See bytecomp.el.
 
 (defun byte-optimize-plus (form)
   (byte-optimize-predicate (byte-optimize-delay-constants-math form 1 '+)))
@@ -729,9 +729,15 @@
       (decf (nth 1 form) last)
       (butlast form))
 
-     ;; (- 0 x ...)  -->  (- (- x) ...)
-     ((and (eq 0 (nth 1 form)) (>= (length form) 3))
-      `(- (- ,(nth 2 form)) ,@(nthcdr 3 form)))
+     ;; (- 0 ...) -->
+     ((eq 0 (nth 1 form))
+      (case (length form)
+	;; (- 0) --> 0
+	(2 0)
+	;; (- 0 x)  -->  (- x)
+	(3 `(- ,(nth 2 form)))
+	;; (- 0 x y ...)  -->  (- (- x) y ...)
+	(t `(- (- ,(nth 2 form)) ,@(nthcdr 3 form)))))
 
      (t (byte-optimize-predicate form)))))
 
@@ -849,13 +855,13 @@
 (put 'max 'byte-optimizer 'byte-optimize-associative-math)
 (put 'min 'byte-optimizer 'byte-optimize-associative-math)
 
-(put '=   'byte-optimizer 'byte-optimize-binary-predicate)
 (put 'eq  'byte-optimizer 'byte-optimize-binary-predicate)
 (put 'eql 'byte-optimizer 'byte-optimize-binary-predicate)
 (put 'equal   'byte-optimizer 'byte-optimize-binary-predicate)
 (put 'string= 'byte-optimizer 'byte-optimize-binary-predicate)
 (put 'string-equal 'byte-optimizer 'byte-optimize-binary-predicate)
 
+(put '=   'byte-optimizer 'byte-optimize-predicate)
 (put '<   'byte-optimizer 'byte-optimize-predicate)
 (put '>   'byte-optimizer 'byte-optimize-predicate)
 (put '<=  'byte-optimizer 'byte-optimize-predicate)