diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testObjectToNumber.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testObjectToNumber.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+function testObjectToNumber() {
+    var o = {valueOf: function()-3};
+    var x = 0;
+    for (var i = 0; i < 10; i++)
+        x -= o;
+    return x;
+}
+assertEq(testObjectToNumber(), 30);