diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_5/extensions/regress-455380.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_5/extensions/regress-455380.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ * Contributor: Robert Sayre
+ */
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 455380;
+var summary = 'Do not assert with JIT: !lhs->isQuad() && !rhs->isQuad()';
+var actual = 'No Crash';
+var expect = 'No Crash';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+jit(true);
+
+const IS_TOKEN_ARRAY =
+  [0, 0, 0, 0, 0, 0, 0, 0, //   0
+   0, 0, 0, 0, 0, 0, 0, 0, //   8
+   0, 0, 0, 0, 0, 0, 0, 0, //  16
+   0, 0, 0, 0, 0, 0, 0, 0, //  24
+
+   0, 1, 0, 1, 1, 1, 1, 1, //  32
+   0, 0, 1, 1, 0, 1, 1, 0, //  40
+   1, 1, 1, 1, 1, 1, 1, 1, //  48
+   1, 1, 0, 0, 0, 0, 0, 0, //  56
+
+   0, 1, 1, 1, 1, 1, 1, 1, //  64
+   1, 1, 1, 1, 1, 1, 1, 1, //  72
+   1, 1, 1, 1, 1, 1, 1, 1, //  80
+   1, 1, 1, 0, 0, 0, 1, 1, //  88
+
+   1, 1, 1, 1, 1, 1, 1, 1, //  96
+   1, 1, 1, 1, 1, 1, 1, 1, // 104
+   1, 1, 1, 1, 1, 1, 1, 1, // 112
+   1, 1, 1, 0, 1, 0, 1];   // 120
+
+const headerUtils = {
+normalizeFieldName: function(fieldName)
+{
+  if (fieldName == "")
+    throw "error: empty string";
+
+  for (var i = 0, sz = fieldName.length; i < sz; i++)
+  {
+    if (!IS_TOKEN_ARRAY[fieldName.charCodeAt(i)])
+    {
+      throw (fieldName + " is not a valid header field name!");
+    }
+  }
+
+  return fieldName.toLowerCase();
+}
+};
+
+headerUtils.normalizeFieldName("Host");
+
+jit(false);
+
+reportCompare(expect, actual, summary);