diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug608980.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug608980.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+
+/* Don't trip bogus assert. */
+
+function foo()
+{
+  var x;
+  while (x = 0) {
+    x = 1;
+  }
+}
+foo();