diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug913749.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug913749.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,20 @@
+y = new Float32Array(11);
+x = [];
+
+Object.defineProperty(x, 18, {
+    get: (function() {
+        y.length;
+    }),
+});
+this.toSource();
+
+y = undefined;
+
+for (var i = 0; i < 3; i++) {
+    try {
+	x.toString();
+	assertEq(0, 1);
+    } catch (e) {
+	assertEq(e.message, "y is undefined");
+    }
+}