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Diffstat (limited to 'contrib/llvm-project/libcxx/include/__algorithm/half_positive.h')
-rw-r--r-- | contrib/llvm-project/libcxx/include/__algorithm/half_positive.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__algorithm/half_positive.h b/contrib/llvm-project/libcxx/include/__algorithm/half_positive.h new file mode 100644 index 000000000000..b03efc495b1a --- /dev/null +++ b/contrib/llvm-project/libcxx/include/__algorithm/half_positive.h @@ -0,0 +1,54 @@ +//===----------------------------------------------------------------------===// +// +// 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___ALGORITHM_HALF_POSITIVE_H +#define _LIBCPP___ALGORITHM_HALF_POSITIVE_H + +#include <__config> +#include <type_traits> + +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +#pragma GCC system_header +#endif + +_LIBCPP_PUSH_MACROS +#include <__undef_macros> + +_LIBCPP_BEGIN_NAMESPACE_STD + +// Perform division by two quickly for positive integers (llvm.org/PR39129) + +template <typename _Integral> +_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR +typename enable_if +< + is_integral<_Integral>::value, + _Integral +>::type +__half_positive(_Integral __value) +{ + return static_cast<_Integral>(static_cast<typename make_unsigned<_Integral>::type>(__value) / 2); +} + +template <typename _Tp> +_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR +typename enable_if +< + !is_integral<_Tp>::value, + _Tp +>::type +__half_positive(_Tp __value) +{ + return __value / 2; +} + +_LIBCPP_END_NAMESPACE_STD + +_LIBCPP_POP_MACROS + +#endif // _LIBCPP___ALGORITHM_HALF_POSITIVE_H |