X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=lisp%2Fbyte-optimize.el;h=c84fd233718771a7b25d43e2c09ea74cd0e20eb9;hb=e3ea44726c8e18395b48337eeeda984c1b23cd44;hp=ff6edde28ddabf5d7194c78f8e04e206752aa17d;hpb=14144012929ab5944f367d5d1b323ab8268abb05;p=chise%2Fxemacs-chise.git.1

diff --git a/lisp/byte-optimize.el b/lisp/byte-optimize.el
index ff6edde..c84fd23 100644
--- a/lisp/byte-optimize.el
+++ b/lisp/byte-optimize.el
@@ -473,12 +473,12 @@
 		 (if (and (cdr form) (null backwards))
 		     (byte-compile-log
 		      "  all subforms of %s called for effect; deleted" form))
-		 (and backwards
-                      ;; Now optimize the rest of the forms. We need the return
-                      ;; values. We already did the car.
-                      (setcdr backwards
-                              (mapcar 'byte-optimize-form (cdr backwards)))
-		      (cons fn (nreverse backwards))))
+		 (when backwards
+		   ;; Now optimize the rest of the forms. We need the return
+		   ;; values. We already did the car.
+		   (setcdr backwards
+			   (mapcar 'byte-optimize-form (cdr backwards))))
+		 (cons fn (nreverse backwards)))
 	     (cons fn (mapcar 'byte-optimize-form (cdr form)))))
 
 	  ((eq fn 'interactive)
@@ -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)