diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testBug504520.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testBug504520.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+function testBug504520() {
+    // A bug involving comparisons.
+    var arr = [1/0, 1/0, 1/0, 1/0, 1/0, 1/0, 1/0, 1/0, 1/0, 0];
+    assertEq(arr.length > 9, true);
+
+    var s = '';
+    for (var i = 0; i < arr.length; i++)
+        arr[i] >= 1/0 ? null : (s += i);
+    assertEq(s, '9');
+}
+testBug504520();