diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 42d7d7837..c6d4be111 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -1,8 +1,6 @@
 ;;; -*- mode: scheme; coding: utf-8; -*-
 
-;;;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
-;;;;   2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014
-;;;;   Free Software Foundation, Inc.
+;;;; Copyright (C) 1995-2014  Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -409,13 +407,15 @@ If there is no handler at all, Guile prints an error and then exits."
   (syntax-rules ()
     ((_) #t)
     ((_ x) x)
-    ((_ x y ...) (if x (and y ...) #f))))
+    ;; Avoid ellipsis, which would lead to quadratic expansion time.
+    ((_ x . y) (if x (and . y) #f))))
 
 (define-syntax or
   (syntax-rules ()
     ((_) #f)
     ((_ x) x)
-    ((_ x y ...) (let ((t x)) (if t t (or y ...))))))
+    ;; Avoid ellipsis, which would lead to quadratic expansion time.
+    ((_ x . y) (let ((t x)) (if t t (or . y))))))
 
 (include-from-path "ice-9/quasisyntax")