diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug916761.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug916761.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+if (typeof ParallelArray === "undefined")
+    quit();
+
+function toString(r) {
+    var result = "";
+    for (var i = 0; i < 5; i++)
+	result += r.get(i);
+    return result;
+}
+Array.prototype[2] = 'y';
+assertEq(toString(new ParallelArray(['x', 'x'])), "xxyundefinedundefined");