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/size_t.h>
16#include <__type_traits/is_constant_evaluated.h>
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
25template <size_t _Np, class _Tp>
26[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp* __assume_aligned(_Tp* __ptr) {
27 static_assert(_Np != 0 && (_Np & (_Np - 1)) == 0, "std::assume_aligned<N>(p) requires N to be a power of two");
28
29 if (__libcpp_is_constant_evaluated()) {
30 (void)__builtin_assume_aligned(__ptr, _Np);
31 return __ptr;
32 } else {
33 _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(
34 reinterpret_cast<uintptr_t>(__ptr) % _Np == 0, "Alignment assumption is violated");
35 return static_cast<_Tp*>(__builtin_assume_aligned(__ptr, _Np));
36 }
37}
38
39#if _LIBCPP_STD_VER >= 20
40
41template <size_t _Np, class _Tp>
42[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp* assume_aligned(_Tp* __ptr) {
43 return std::__assume_aligned<_Np>(__ptr);
44}
45
46#endif // _LIBCPP_STD_VER >= 20
47
48_LIBCPP_END_NAMESPACE_STD
49
50#endif // _LIBCPP___MEMORY_ASSUME_ALIGNED_H
51