Implement C++20 p0879 - Constexpr for swap and swap related functions.

[thirdparty/gcc.git] / libstdc++-v3 / testsuite / 25_algorithms / iter_swap / constexpr.cc

diff --git a/libstdc++-v3/testsuite/25_algorithms/iter_swap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/iter_swap/constexpr.cc
new file mode 100644 (file)
index 0000000..9444bf4
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/iter_swap/constexpr.cc
@@ -0,0 +1,42 @@
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <algorithm>
+#include <array>
+
+#ifndef __cpp_lib_constexpr_swap_algorithms
+# error "Feature-test macro for constexpr swap algorithms missing"
+#elif __cpp_lib_constexpr_swap_algorithms < 201806L
+# error "Feature-test macro for constexpr swap algorithms has wrong value"
+#endif
+
+constexpr bool
+test()
+{
+  auto ok = true;
+
+  std::array<int, 12> ar0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
+
+  std::iter_swap(ar0.begin() + 2, ar0.begin() + 5);
+
+  return ok = ar0[2] == 5 && ar0[5] == 2;
+}
+
+static_assert(test());