diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug820124-4.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug820124-4.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+// Don't assert.
+eval("\
+    r = RegExp(\"(?!()(((!))))\", \"g\");\
+    \"^\".replace(r, '');\
+    r = (\"1+\")\
+")
+gc()
+RegExp.$8