diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/auto-regress/bug691593.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/auto-regress/bug691593.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,18 @@
+// Binary: cache/js-dbg-64-acf3c1fb7c94-linux
+// Flags:
+//
+
+genexp = "x * x for (x in [])";
+genexpParened = "(" + genexp + ")";
+needParens(2, "if (1, xx) { }");
+function needParens(section, pat, exp) {
+  ft = pat.replace(/xx/, genexpParened);
+  try {
+    f = new Function(ft);
+  } catch(e) {  }
+  overParenTest(section, f, exp);
+}
+function overParenTest(section, f, exp) {
+  var uf = "" + f;
+  if (uf.indexOf(genexpParened) != -1) {  }
+}