diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/jaeger/bug663910.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/jaeger/bug663910.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,22 @@
+var otherGlobalSameCompartment = newGlobal("same-compartment");
+eval = otherGlobalSameCompartment.eval;
+doesNotNeedParens(1, "if (xx) { }");
+needParens(2, "if (1, xx) { }");
+function doesNotNeedParens(section, pat) {
+    try {
+        f = new Function
+    } catch (e) {}
+    roundTripTest(section, f)
+}
+function needParens(section, pat, exp) {
+    var f, ft;
+    roundTripTest(section, f, exp)
+}
+function roundTripTest(section, f, exp) {
+    uf = "" + f
+    var euf;
+    try {
+      euf = eval("(" + uf + ")");
+    } catch (e) { }
+    + euf
+}