diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug734383.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug734383.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+function foo(a, b) {
+    var s = "foo";
+    for (var j = 0; j < 5; j++)
+        s += a[b[j]];
+    return s;
+}
+
+var a = {a:"zero", b:"one", c:"two", d:"three", e:"four"};
+var b = ["a", "b", "c", "d", "e"];
+
+for (var i=0; i<9; i++)
+    assertEq(foo(a, b), "foozeroonetwothreefour");
+
+a.e = 4;
+assertEq(foo(a, b), "foozeroonetwothree4");