diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug641491.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug641491.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,19 @@
+function f1() {
+}
+function f2() {
+}
+function f3(o) {
+    f2 = Date.prototype;
+}
+var key = Object.getOwnPropertyNames(f1)[30];
+if(key) {
+    f3 = f1[key];
+}
+gc(); 
+gc();
+try {
+for(var i=0; i<10; i++) {
+    delete f2[1];
+    f3(function() {});
+}
+} catch (e) {}