1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___MEMORY_ASSUME_ALIGNED_H 11 #define _LIBCPP___MEMORY_ASSUME_ALIGNED_H 12 13 #include <__assert> 14 #include <__config> 15 #include <__type_traits/is_constant_evaluated.h> 16 #include <cstddef> 17 #include <cstdint> 18 19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20 # pragma GCC system_header 21 #endif 22 23 _LIBCPP_BEGIN_NAMESPACE_STD 24 25 #if _LIBCPP_STD_VER > 17 26 27 template <size_t _Np, class _Tp> 28 [[nodiscard]] 29 _LIBCPP_HIDE_FROM_ABI 30 constexpr _Tp* assume_aligned(_Tp* __ptr) { 31 static_assert(_Np != 0 && (_Np & (_Np - 1)) == 0, 32 "std::assume_aligned<N>(p) requires N to be a power of two"); 33 34 if (is_constant_evaluated()) { 35 return __ptr; 36 } else { 37 _LIBCPP_ASSERT(reinterpret_cast<uintptr_t>(__ptr) % _Np == 0, "Alignment assumption is violated"); 38 return static_cast<_Tp*>(__builtin_assume_aligned(__ptr, _Np)); 39 } 40 } 41 42 #endif // _LIBCPP_STD_VER > 17 43 44 _LIBCPP_END_NAMESPACE_STD 45 46 #endif // _LIBCPP___MEMORY_ASSUME_ALIGNED_H 47