| 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 <cstddef> |
| 16 | #include <cstdint> |
| 17 | #include <type_traits> // for is_constant_evaluated() |
| 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 |