diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_3/RegExp/regress-334158.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_3/RegExp/regress-334158.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 334158;
+var summary = 'Parse error in control letter escapes (RegExp)';
+var actual = '';
+var expect = '';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+expect = true;
+actual = /\ca/.test( "\x01" ); 
+reportCompare(expect, actual, summary + ':/\ca/.test( "\x01" )');
+
+expect = false
+  actual = /\ca/.test( "\\ca" );
+reportCompare(expect, actual, summary + ': /\ca/.test( "\\ca" )');
+
+expect = false
+  actual = /\c[a/]/.test( "\x1ba/]" );
+reportCompare(expect, actual, summary + ': /\c[a/]/.test( "\x1ba/]" )');