diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testConvertibleObjectEqUndefined.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testConvertibleObjectEqUndefined.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,30 @@
+function x4(v) { return "" + v + v + v + v; }
+function testConvertibleObjectEqUndefined()
+{
+  var compares =
+    [
+     false, false, false, false,
+     undefined, undefined, undefined, undefined,
+     false, false, false, false,
+     undefined, undefined, undefined, undefined,
+     false, false, false, false,
+     undefined, undefined, undefined, undefined,
+     false, false, false, false,
+     undefined, undefined, undefined, undefined,
+     false, false, false, false,
+     undefined, undefined, undefined, undefined,
+    ];
+  var count = 0;
+  var obj = { valueOf: function() { count++; return 1; } };
+  var results = compares.map(function(v) { return "unwritten"; });
+
+  for (var i = 0, sz = compares.length; i < sz; i++)
+    results[i] = compares[i] == obj;
+
+  return results.join("") + count;
+}
+
+assertEq(testConvertibleObjectEqUndefined(),  
+	 x4(false) + x4(false) + x4(false) + x4(false) + x4(false) + x4(false) +
+	 x4(false) + x4(false) + x4(false) + x4(false) + "20");
+