* lisp/emacs-lisp/byte-opt.el (byte-optimize-binary-predicate): Don't assume

there can't be more than 2 arguments.

Fixes: debbugs:17584

2 files changed, 15 insertions, 8 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 1b886000014..fe34854ab53 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-27  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * emacs-lisp/byte-opt.el (byte-optimize-binary-predicate): Don't assume
+        there can't be more than 2 arguments (bug#17584).
+
 2014-05-27  Glenn Morris  <rgm@gnu.org>
 
         * simple.el (filter-buffer-substring-functions)
diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index b1e06410da4..fe6640cc51e 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -859,14 +859,16 @@
 
 
 (defun byte-optimize-binary-predicate (form)
-  (if (macroexp-const-p (nth 1 form))
-      (if (macroexp-const-p (nth 2 form))
-          (condition-case ()
-              (list 'quote (eval form))
-            (error form))
-        ;; This can enable some lapcode optimizations.
-        (list (car form) (nth 2 form) (nth 1 form)))
-    form))
+  (cond
+   ((or (not (macroexp-const-p (nth 1 form)))
+        (nthcdr 3 form)) ;; In case there are more than 2 args.
+    form)
+   ((macroexp-const-p (nth 2 form))
+    (condition-case ()
+        (list 'quote (eval form))
+      (error form)))
+   (t ;; This can enable some lapcode optimizations.
+    (list (car form) (nth 2 form) (nth 1 form)))))
 
 (defun byte-optimize-predicate (form)
   (let ((ok t)