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