Index: canonical.php
===================================================================
--- canonical.php	(revision 21566)
+++ canonical.php	(working copy)
@@ -405,7 +405,7 @@
 			$redirect_url .= '?' . $redirect['query'];
 	}
 
-	if ( !$redirect_url || $redirect_url == $requested_url )
+	if ( !$redirect_url || strcasecmp($redirect_url, $requested_url) == 0 )
 		return false;
 
 	// Hex encoded octets are case-insensitive.
@@ -421,7 +421,7 @@
 	// Note that you can use the "redirect_canonical" filter to cancel a canonical redirect for whatever reason by returning false
 	$redirect_url = apply_filters('redirect_canonical', $redirect_url, $requested_url);
 
-	if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
+	if ( !$redirect_url || strcasecmp($redirect_url, $requested_url) == 0 ) // yes, again -- in case the filter aborted the request
 		return false;
 
 	if ( $do_redirect ) {