testsuite: add infinite recursion test case [PR63388]

gcc/testsuite/ChangeLog:
	PR c++/63388
	* g++.dg/analyzer/infinite-recursion-pr63388.C: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

gcc/testsuite/g++.dg/analyzer/infinite-recursion-pr63388.C

@@ -0,0 +1,21 @@
+// { dg-do compile { target c++11 } }
+
+namespace std
+{
+  class ostream;
+  extern ostream cout;
+}
+
+enum class Month {jan=1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec};
+
+std::ostream& operator<<(std::ostream& os, Month m)
+{
+  return os << m; // { dg-warning "infinite recursion" }
+}
+
+int main()
+{
+  Month m = Month::may;
+  std::cout << m;
+  return 0;
+}