Make std::get constexpr

llvm-svn: 186525

1 files changed, 62 insertions, 0 deletions

diff --git a/libcxx/test/containers/sequences/array/front_back.pass.cpp b/libcxx/test/containers/sequences/array/front_back.pass.cpp
new file mode 100644
index 00000000000..45a963b9947
--- /dev/null
+++ b/libcxx/test/containers/sequences/array/front_back.pass.cpp
@@ -0,0 +1,62 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+
+// reference front();
+// reference back();
+// const_reference front(); // constexpr in C++14
+// const_reference back(); // constexpr in C++14
+
+#include <array>
+#include <cassert>
+
+int main()
+{
+    {
+        typedef double T;
+        typedef std::array<T, 3> C;
+        C c = {1, 2, 3.5};
+
+        C::reference r1 = c.front();
+        assert(r1 == 1);
+        r1 = 5.5;
+        assert(c[0] == 5.5);
+        
+        C::reference r2 = c.back();
+        assert(r2 == 3.5);
+        r2 = 7.5;
+        assert(c[2] == 7.5);
+    }
+    {
+        typedef double T;
+        typedef std::array<T, 3> C;
+        const C c = {1, 2, 3.5};
+        C::const_reference r1 = c.front();
+        assert(r1 == 1);
+
+        C::const_reference r2 = c.back();
+        assert(r2 == 3.5);
+    }
+
+#if _LIBCPP_STD_VER > 11 
+    {
+        typedef double T;
+        typedef std::array<T, 3> C;
+        constexpr C c = {1, 2, 3.5};
+        
+        constexpr T t1 = c.front();
+        static_assert (t1 == 1, "");
+
+        constexpr T t2 = c.back();
+        static_assert (t2 == 3.5, "");
+    }
+#endif
+
+}