zig/lib/libcxx/include/__compare/synth_three_way.h
Andrew Kelley 5d4439cc3e libcxx: update to LLVM 17
release/17.x branch, commit 8f4dd44097c9ae25dd203d5ac87f3b48f854bba8

This adds the flag `-D_LIBCPP_PSTL_CPU_BACKEND_SERIAL`. A future
enhancement could possibly pass something different if there is a
compelling parallel implementation. That libdispatch one might be worth
looking into.
2023-09-19 09:37:31 -07:00

57 lines
1.7 KiB
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Vendored

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___COMPARE_SYNTH_THREE_WAY_H
#define _LIBCPP___COMPARE_SYNTH_THREE_WAY_H
#include <__compare/ordering.h>
#include <__compare/three_way_comparable.h>
#include <__concepts/boolean_testable.h>
#include <__config>
#include <__utility/declval.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
// [expos.only.func]
// TODO MODULES restore the lamba to match the Standard.
// See https://github.com/llvm/llvm-project/issues/57222
//_LIBCPP_HIDE_FROM_ABI inline constexpr auto __synth_three_way =
// []<class _Tp, class _Up>(const _Tp& __t, const _Up& __u)
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr auto __synth_three_way(const _Tp& __t, const _Up& __u)
requires requires {
{ __t < __u } -> __boolean_testable;
{ __u < __t } -> __boolean_testable;
}
{
if constexpr (three_way_comparable_with<_Tp, _Up>) {
return __t <=> __u;
} else {
if (__t < __u)
return weak_ordering::less;
if (__u < __t)
return weak_ordering::greater;
return weak_ordering::equivalent;
}
}
template <class _Tp, class _Up = _Tp>
using __synth_three_way_result = decltype(std::__synth_three_way(std::declval<_Tp&>(), std::declval<_Up&>()));
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___COMPARE_SYNTH_THREE_WAY_H