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//===----------------------------------------------------------------------===//
//
// 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___ATOMIC_FLOATING_POINT_HELPER_H
#define _LIBCPP___ATOMIC_FLOATING_POINT_HELPER_H
#include <__config>
#include <__type_traits/is_floating_point.h>
#include <__type_traits/is_same.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool __is_fp80_long_double() {
// Only x87-fp80 long double has 64-bit mantissa
return __LDBL_MANT_DIG__ == 64 && std::is_same_v<_Tp, long double>;
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool __has_rmw_builtin() {
static_assert(std::is_floating_point_v<_Tp>);
# ifndef _LIBCPP_COMPILER_CLANG_BASED
return false;
# else
// The builtin __cxx_atomic_fetch_add errors during compilation for
// long double on platforms with fp80 format.
// For more details, see
// lib/Sema/SemaChecking.cpp function IsAllowedValueType
// LLVM Parser does not allow atomicrmw with x86_fp80 type.
// if (ValType->isSpecificBuiltinType(BuiltinType::LongDouble) &&
// &Context.getTargetInfo().getLongDoubleFormat() ==
// &llvm::APFloat::x87DoubleExtended())
// For more info
// https://llvm.org/PR68602
// https://reviews.llvm.org/D53965
return !std::__is_fp80_long_double<_Tp>();
# endif
}
#endif
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ATOMIC_FLOATING_POINT_HELPER_H
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