From 29669521665c5e82a8548ef0a7f642634a042d48 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 8 Nov 2019 00:37:08 +0000 Subject: [PATCH] libstdc++: define std::common_comparison_category for C++20 * libsupc++/compare (common_comparison_category) (common_comparison_category_t): Define for C++20. * testsuite/18_support/comparisons/common/1.cc: New test. From-SVN: r277943 --- libstdc++-v3/ChangeLog | 4 + libstdc++-v3/libsupc++/compare | 99 +++++++++++++++---- .../18_support/comparisons/common/1.cc | 48 +++++++++ 3 files changed, 133 insertions(+), 18 deletions(-) create mode 100644 libstdc++-v3/testsuite/18_support/comparisons/common/1.cc diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 31399142ab8..65e55d097a6 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,5 +1,9 @@ 2019-11-07 Jonathan Wakely + * libsupc++/compare (common_comparison_category) + (common_comparison_category_t): Define for C++20. + * testsuite/18_support/comparisons/common/1.cc: New test. + * include/bits/stl_algo.h (for_each_n): Handle negative count. * testsuite/25_algorithms/for_each/for_each_n_debug.cc: New test. diff --git a/libstdc++-v3/libsupc++/compare b/libstdc++-v3/libsupc++/compare index 84cc3f5c85f..94728e29de8 100644 --- a/libstdc++-v3/libsupc++/compare +++ b/libstdc++-v3/libsupc++/compare @@ -385,18 +385,81 @@ namespace std is_gteq(partial_ordering __cmp) noexcept { return __cmp >= 0; } +#if __cpp_lib_concepts + namespace __detail + { + template + inline constexpr unsigned __cmp_cat_id = 1; + template<> + inline constexpr unsigned __cmp_cat_id = 2; + template<> + inline constexpr unsigned __cmp_cat_id = 4; + template<> + inline constexpr unsigned __cmp_cat_id = 8; + + template + constexpr unsigned __cmp_cat_ids() + { return (__cmp_cat_id<_Ts> | ...); } + + template + struct __common_cmp_cat; + + // If any Ti is not a comparison category type, U is void. + template + requires ((_Bits & 1) == 1) + struct __common_cmp_cat<_Bits> { using type = void; }; + + // Otherwise, if at least one Ti is std::partial_ordering, + // U is std::partial_ordering. + template + requires ((_Bits & 0b1001) == 0b1000) + struct __common_cmp_cat<_Bits> { using type = partial_ordering; }; + + // Otherwise, if at least one Ti is std::weak_ordering, + // U is std::weak_ordering. + template + requires ((_Bits & 0b1101) == 0b0100) + struct __common_cmp_cat<_Bits> { using type = weak_ordering; }; + + // Otherwise, U is std::strong_ordering. + template<> + struct __common_cmp_cat<0b0010> { using type = strong_ordering; }; + } // namespace __detail + // [cmp.common], common comparison category type template struct common_comparison_category { - // using type = TODO + using type + = __detail::__common_cmp_cat<__detail::__cmp_cat_ids<_Ts...>()>::type; }; + // Partial specializations for one and zero argument cases. + + template + struct common_comparison_category<_Tp> + { using type = void; }; + + template<> + struct common_comparison_category + { using type = partial_ordering; }; + + template<> + struct common_comparison_category + { using type = weak_ordering; }; + + template<> + struct common_comparison_category + { using type = strong_ordering; }; + + template<> + struct common_comparison_category<> + { using type = strong_ordering; }; + template using common_comparison_category_t = typename common_comparison_category<_Ts...>::type; -#if __cpp_lib_concepts namespace __detail { template @@ -493,22 +556,22 @@ namespace std template requires (three_way_comparable_with<_Tp, _Up> || __detail::__3way_builtin_ptr_cmp<_Tp, _Up>) - constexpr auto - operator()(_Tp&& __t, _Up&& __u) const noexcept - { - if constexpr (__detail::__3way_builtin_ptr_cmp<_Tp, _Up>) - { - auto __pt = static_cast(__t); - auto __pu = static_cast(__u); - if (__builtin_is_constant_evaluated()) - return __pt <=> __pu; - auto __it = reinterpret_cast<__UINTPTR_TYPE__>(__pt); - auto __iu = reinterpret_cast<__UINTPTR_TYPE__>(__pu); - return __it <=> __iu; - } - else - return static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u); - } + constexpr auto + operator()(_Tp&& __t, _Up&& __u) const noexcept + { + if constexpr (__detail::__3way_builtin_ptr_cmp<_Tp, _Up>) + { + auto __pt = static_cast(__t); + auto __pu = static_cast(__u); + if (__builtin_is_constant_evaluated()) + return __pt <=> __pu; + auto __it = reinterpret_cast<__UINTPTR_TYPE__>(__pt); + auto __iu = reinterpret_cast<__UINTPTR_TYPE__>(__pu); + return __it <=> __iu; + } + else + return static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u); + } using is_transparent = void; }; diff --git a/libstdc++-v3/testsuite/18_support/comparisons/common/1.cc b/libstdc++-v3/testsuite/18_support/comparisons/common/1.cc new file mode 100644 index 00000000000..015a8acae97 --- /dev/null +++ b/libstdc++-v3/testsuite/18_support/comparisons/common/1.cc @@ -0,0 +1,48 @@ +// 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 +// . + +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } + +#include + +template +constexpr bool check() +{ + return std::same_as>; +} + +using std::partial_ordering; +using std::weak_ordering; +using std::strong_ordering; + +static_assert(check()); +static_assert(check()); +static_assert(check()); +static_assert(check()); +static_assert(check()); +static_assert(check()); +static_assert(check()); + +using PO = std::partial_ordering; +using WO = std::weak_ordering; +using SO = std::strong_ordering; + +static_assert(check()); +static_assert(check()); +static_assert(check()); +static_assert(check());