diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/auto-regress/bug783421.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/auto-regress/bug783421.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,30 @@
+// Binary: cache/js-dbg-64-50e4ff05741e-linux
+// Flags: -m -n -a
+//
+gc()
+var p = n
+function m() {
+  return function(f, code, t) {
+	try {
+	  evalcx(code, newGlobal())
+	} catch (e) {}
+  }
+}
+function n() {
+	f()
+}
+function h(code) {
+	f = Function(code)
+	p(f, code, true)
+}
+h("\
+  p=m();\
+  gcPreserveCode();\
+  gcslice(7);\
+")
+h("\"\"")
+h("")
+h("gc()")
+h("")
+h("")
+h("gczeal(4,2)")