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1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___COMPARE_SYNTH_THREE_WAY_H10#define _LIBCPP___COMPARE_SYNTH_THREE_WAY_H11 12#include <__compare/ordering.h>13#include <__compare/three_way_comparable.h>14#include <__concepts/boolean_testable.h>15#include <__config>16#include <__utility/declval.h>17 18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)19# pragma GCC system_header20#endif21 22_LIBCPP_BEGIN_NAMESPACE_STD23 24#if _LIBCPP_STD_VER >= 2025 26// [expos.only.func]27 28_LIBCPP_HIDE_FROM_ABI inline constexpr auto __synth_three_way = []<class _Tp, class _Up>(const _Tp& __t, const _Up& __u)29 requires requires {30 { __t < __u } -> __boolean_testable;31 { __u < __t } -> __boolean_testable;32 }33{34 if constexpr (three_way_comparable_with<_Tp, _Up>) {35 return __t <=> __u;36 } else {37 if (__t < __u)38 return weak_ordering::less;39 if (__u < __t)40 return weak_ordering::greater;41 return weak_ordering::equivalent;42 }43};44 45template <class _Tp, class _Up = _Tp>46using __synth_three_way_result _LIBCPP_NODEBUG =47 decltype(std::__synth_three_way(std::declval<_Tp&>(), std::declval<_Up&>()));48 49#endif // _LIBCPP_STD_VER >= 2050 51_LIBCPP_END_NAMESPACE_STD52 53#endif // _LIBCPP___COMPARE_SYNTH_THREE_WAY_H54