| //===----------------------------------------------------------------------===// |
| // |
| // 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___BIT_BIT_CEIL_H |
| #define _LIBCPP___BIT_BIT_CEIL_H |
| |
| #include <__assert> |
| #include <__bit/countl.h> |
| #include <__concepts/arithmetic.h> |
| #include <__config> |
| #include <limits> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER >= 20 |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_ceil(_Tp __t) noexcept { |
| if (__t < 2) |
| return 1; |
| const unsigned __n = numeric_limits<_Tp>::digits - std::countl_zero((_Tp)(__t - 1u)); |
| _LIBCPP_ASSERT(__n != numeric_limits<_Tp>::digits, "Bad input to bit_ceil"); |
| |
| if constexpr (sizeof(_Tp) >= sizeof(unsigned)) |
| return _Tp{1} << __n; |
| else { |
| const unsigned __extra = numeric_limits<unsigned>::digits - numeric_limits<_Tp>::digits; |
| const unsigned __retVal = 1u << (__n + __extra); |
| return (_Tp)(__retVal >> __extra); |
| } |
| } |
| |
| #endif // _LIBCPP_STD_VER >= 20 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___BIT_BIT_CEIL_H |