1 files changed, 21 insertions, 8 deletions

diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index c955a6aa0f2..24770a12197 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -1,9 +1,10 @@
 ;;; byte-opt.el --- the optimization passes of the emacs-lisp byte compiler.
 
-;;; Copyright (c) 1991, 1994 Free Software Foundation, Inc.
+;;; Copyright (c) 1991, 1994, 2000 Free Software Foundation, Inc.
 
 ;; Author: Jamie Zawinski <jwz@lucid.com>
 ;;      Hallvard Furuseth <hbf@ulrik.uio.no>
+;; Maintainer: FSF
 ;; Keywords: internal
 
 ;; This file is part of GNU Emacs.
@@ -592,9 +593,10 @@
 ;; I'd like this to be a defsubst, but let's not be self-referential...
 (defmacro byte-compile-trueconstp (form)
   ;; Returns non-nil if FORM is a non-nil constant.
-  (` (cond ((consp (, form)) (eq (car (, form)) 'quote))
-           ((not (symbolp (, form))))
-           ((eq (, form) t)))))
+  `(cond ((consp ,form) (eq (car ,form) 'quote))
+         ((not (symbolp ,form)))
+         ((eq ,form t))
+         ((keywordp ,form))))
 
 ;; If the function is being called with constant numeric args,
 ;; evaluate as much as possible at compile-time.  This optimizer 
@@ -895,7 +897,7 @@
 (defun byte-optimize-quote (form)
   (if (or (consp (nth 1 form))
           (and (symbolp (nth 1 form))
-               (not (memq (nth 1 form) '(nil t)))))
+               (not (byte-compile-const-symbol-p form))))
       form
     (nth 1 form)))
 
@@ -1116,6 +1118,14 @@
         ((= 1 (safe-length form))
          '(forward-char -1))
         (t form)))
+
+(put 'char-before 'byte-optimizer 'byte-optimize-char-before)
+(defun byte-optimize-char-before (form)
+  (cond ((= 2 (safe-length form))
+         `(char-after (1- ,(nth 1 form))))
+        ((= 1 (safe-length form))
+         '(char-after (1- (point))))
+        (t form)))
 
 ;;; enumerating those functions which need not be called if the returned 
 ;;; value is not used.  That is, something like
@@ -1132,7 +1142,8 @@
          assoc assq
          boundp buffer-file-name buffer-local-variables buffer-modified-p
          buffer-substring
-         capitalize car-less-than-car car cdr ceiling concat coordinates-in-window-p
+         capitalize car-less-than-car car cdr ceiling concat
+         coordinates-in-window-p
          char-width copy-marker cos count-lines
          default-boundp default-value documentation downcase
          elt exp expt fboundp featurep
@@ -1143,7 +1154,8 @@
          hash-table-count
          int-to-string
          keymap-parent
-         length local-variable-if-set-p local-variable-p log log10 logand logb logior lognot logxor lsh
+         length local-variable-if-set-p local-variable-p log log10 logand
+         logb logior lognot logxor lsh
          marker-buffer max member memq min mod
          next-window nth nthcdr number-to-string
          parse-colon-path prefix-numeric-value previous-window
@@ -1484,7 +1496,8 @@
                  (if (memq (car lap0) '(byte-constant byte-dup))
                      (progn
                        (setq tmp (if (or (not tmp)
-                                         (memq (car (cdr lap0)) '(nil t)))
+                                         (byte-compile-const-symbol-p
+                                          (car (cdr lap0))))
                                      (cdr lap0)
                                    (byte-compile-get-constant t)))
                        (byte-compile-log-lap "  %s %s %s\t-->\t%s %s %s"