c++: Add test for PR91607.

     PR c++/91607
     * g++.dg/cpp0x/constexpr-const3.C: New.

diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-const3.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-const3.C
new file mode 100644 (file)
index 0000000..83e3155
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-const3.C
@@ -0,0 +1,12 @@
+// PR c++/91607
+// { dg-do compile { target c++11 } }
+
+enum A { a };
+constexpr A f(const A x) { return x; }
+
+int main()
+{
+  constexpr A a0 = f(a);
+  constexpr A a1 {};
+  constexpr A a2 = f(a1);
+}