diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug904315.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug904315.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+
+function g(o, idx, exp) {
+    for (var i=0; i<3000; i++) {
+	assertEq(o[idx], exp);
+    }
+}
+function f() {
+    var o = [];
+    for (var i=1; i<100; i++) {
+	o[-i] = 1;
+    }
+    g(o, 50, undefined);
+    g(o, -50, 1);
+}
+f();