From 79f31e3d18c959c70dc2dd4076f695eca88b5383 Mon Sep 17 00:00:00 2001
From: Edward Smith-Rowland <3dw4rd@verizon.net>
Date: Sat, 8 Jun 2019 22:18:36 +0000
Subject: [PATCH] Test for C++20 p0858 - ConstexprIterator requirements.

2019-06-08  Edward Smith-Rowland  <3dw4rd@verizon.net>

	Test for C++20 p0858 - ConstexprIterator requirements.
	* testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:
	New test.
	* testsuite/23_containers/array/requirements/constexpr_iter.cc:
	New test.

From-SVN: r272085
---
 libstdc++-v3/ChangeLog                        |  8 ++++
 .../requirements/constexpr_iter.cc            | 42 +++++++++++++++++++
 .../array/requirements/constexpr_iter.cc      | 41 ++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc
 create mode 100644 libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index e20d0b654c3..0abbaa92c93 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,11 @@
+2019-06-08  Edward Smith-Rowland  <3dw4rd@verizon.net>
+
+	Test for C++20 p0858 - ConstexprIterator requirements.
+	* testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:
+	New test.
+	* testsuite/23_containers/array/requirements/constexpr_iter.cc:
+	New test.
+
 2019-06-07  Thomas Rodgers  <trodgers@redhat.com>
 
 	Rename PSTL macro's consistent with libstdc++ (and llvm upstream
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc
new file mode 100644
index 00000000000..24ab502372a
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc
@@ -0,0 +1,42 @@
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+//
+// 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/>.
+
+#include <string_view>
+#include <array>
+
+constexpr char
+test()
+{
+  constexpr std::string_view hw("Hello, World!");
+  static_assert('H' == *hw.begin());
+  auto ch = hw[4];
+  static_assert('W' == *(hw.cbegin() + 7));
+
+  std::array<int, hw.size()> a2{{0,0,0,0,0,0,0,0,0,0,0,0,0}};
+  std::copy(hw.begin(), hw.end(), a2.begin());
+
+  return *(hw.cbegin() + 3);
+}
+
+void
+run_test()
+{
+  constexpr char ch = test();
+}
diff --git a/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc b/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc
new file mode 100644
index 00000000000..88d69d2f8c7
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc
@@ -0,0 +1,41 @@
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+//
+// 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/>.
+
+#include <array>
+
+constexpr int
+test()
+{
+  constexpr std::array<int, 3> a1{{1, 2, 3}};
+  static_assert(1 == *a1.begin());
+  auto n = a1[0] * a1[1]* a1[2];
+  static_assert(1 == *a1.cbegin());
+
+  std::array<int, 3> a2{{0, 0, 0}};
+  std::copy(a1.begin(), a1.end(), a2.begin());
+
+  return n;
+}
+
+void
+run_test()
+{
+  constexpr int n = test();
+}
-- 
2.30.2