[libcxx] r294165 - Implement LWG 2773 - std::ignore should be constexpr.
Eric Fiselier via cfe-commits
cfe-commits at lists.llvm.org
Sun Feb 5 17:25:32 PST 2017
Author: ericwf
Date: Sun Feb 5 19:25:31 2017
New Revision: 294165
URL: http://llvm.org/viewvc/llvm-project?rev=294165&view=rev
Log:
Implement LWG 2773 - std::ignore should be constexpr.
In addition to the PR for LWG 2773 this patch also ensures
that each of std::ignores constructors or assignment operators
are constexpr.
Added:
libcxx/trunk/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
Modified:
libcxx/trunk/include/tuple
libcxx/trunk/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
libcxx/trunk/www/cxx1z_status.html
Modified: libcxx/trunk/include/tuple
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/tuple?rev=294165&r1=294164&r2=294165&view=diff
==============================================================================
--- libcxx/trunk/include/tuple (original)
+++ libcxx/trunk/include/tuple Sun Feb 5 19:25:31 2017
@@ -1064,11 +1064,13 @@ template <class _Up>
struct __ignore_t
{
template <class _Tp>
- _LIBCPP_INLINE_VISIBILITY
- const __ignore_t& operator=(_Tp&&) const {return *this;}
+ _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+ const __ignore_t& operator=(_Tp&&) const {return *this;}
};
-namespace { const __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>(); }
+namespace {
+ constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
+}
template <class _Tp>
struct __make_tuple_return_impl
Added: libcxx/trunk/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/utilities/tuple/tuple.general/ignore.pass.cpp?rev=294165&view=auto
==============================================================================
--- libcxx/trunk/test/std/utilities/tuple/tuple.general/ignore.pass.cpp (added)
+++ libcxx/trunk/test/std/utilities/tuple/tuple.general/ignore.pass.cpp Sun Feb 5 19:25:31 2017
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// 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.
+//
+//===----------------------------------------------------------------------===//
+
+// <tuple>
+
+// constexpr unspecified ignore;
+
+// UNSUPPORTED: c++98, c++03
+
+#include <tuple>
+#include <cassert>
+
+#include "test_macros.h"
+
+constexpr bool test_ignore_constexpr()
+{
+#if TEST_STD_VER > 11
+ { // Test that std::ignore provides constexpr converting assignment.
+ auto& res = (std::ignore = 42);
+ assert(&res == &std::ignore);
+ }
+ { // Test that std::ignore provides constexpr copy/move constructors
+ auto copy = std::ignore;
+ auto moved = std::move(copy);
+ ((void)moved);
+ }
+ { // Test that std::ignore provides constexpr copy/move assignment
+ auto copy = std::ignore;
+ copy = std::ignore;
+ auto moved = std::ignore;
+ moved = std::move(copy);
+ }
+#endif
+ return true;
+}
+
+int main() {
+ {
+ constexpr auto& ignore_v = std::ignore;
+ ((void)ignore_v);
+ }
+ {
+ static_assert(test_ignore_constexpr(), "");
+ }
+#if defined(_LIBCPP_VERSION)
+ {
+ static_assert(std::is_trivial<decltype(std::ignore)>::value, "");
+ }
+#endif
+}
Modified: libcxx/trunk/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp?rev=294165&r1=294164&r2=294165&view=diff
==============================================================================
--- libcxx/trunk/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp (original)
+++ libcxx/trunk/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp Sun Feb 5 19:25:31 2017
@@ -22,6 +22,24 @@
#include "test_macros.h"
+#if TEST_STD_VER > 11
+constexpr bool test_tie_constexpr() {
+ {
+ int i = 42;
+ double f = 1.1;
+ using ExpectT = std::tuple<int&, decltype(std::ignore)&, double&>;
+ auto res = std::tie(i, std::ignore, f);
+ static_assert(std::is_same<ExpectT, decltype(res)>::value, "");
+ assert(&std::get<0>(res) == &i);
+ assert(&std::get<1>(res) == &std::ignore);
+ assert(&std::get<2>(res) == &f);
+ // FIXME: If/when tuple gets constexpr assignment
+ //res = std::make_tuple(101, nullptr, -1.0);
+ }
+ return true;
+}
+#endif
+
int main()
{
{
@@ -39,5 +57,8 @@ int main()
static_assert ( std::get<0>(t) == 42, "" );
static_assert ( std::get<1>(t) == 1.1, "" );
}
+ {
+ static_assert(test_tie_constexpr(), "");
+ }
#endif
}
Modified: libcxx/trunk/www/cxx1z_status.html
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/www/cxx1z_status.html?rev=294165&r1=294164&r2=294165&view=diff
==============================================================================
--- libcxx/trunk/www/cxx1z_status.html (original)
+++ libcxx/trunk/www/cxx1z_status.html Sun Feb 5 19:25:31 2017
@@ -407,7 +407,7 @@
<tr><td><a href="http://wg21.link/LWG2767">2767</a></td><td>not_fn call_wrapper can form invalid types</td><td>Issaquah</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2769">2769</a></td><td>Redundant const in the return type of any_cast(const any&)</td><td>Issaquah</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2771">2771</a></td><td>Broken Effects of some basic_string::compare functions in terms of basic_string_view</td><td>Issaquah</td><td>Complete</td></tr>
- <tr><td><a href="http://wg21.link/LWG2773">2773</a></td><td>Making std::ignore constexpr</td><td>Issaquah</td><td></td></tr>
+ <tr><td><a href="http://wg21.link/LWG2773">2773</a></td><td>Making std::ignore constexpr</td><td>Issaquah</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2777">2777</a></td><td>basic_string_view::copy should use char_traits::copy</td><td>Issaquah</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2778">2778</a></td><td>basic_string_view is missing constexpr</td><td>Issaquah</td><td>Complete</td></tr>
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