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1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___ALGORITHM_SIMD_UTILS_H
10#define _LIBCPP___ALGORITHM_SIMD_UTILS_H
11
12#include <__algorithm/min.h>
13#include <__bit/bit_cast.h>
14#include <__bit/countl.h>
15#include <__bit/countr.h>
16#include <__config>
17#include <__cstddef/size_t.h>
18#include <__utility/integer_sequence.h>
19#include <cstdint>
20
21#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22# pragma GCC system_header
23#endif
24
25_LIBCPP_PUSH_MACROS
26#include <__undef_macros>
27
28// TODO: Find out how altivec changes things and allow vectorizations there too.
29// TODO: Simplify this condition once we stop building with AppleClang 15 in the CI.
30#if _LIBCPP_STD_VER >= 14 && defined(_LIBCPP_COMPILER_CLANG_BASED) && !defined(__ALTIVEC__) && \
31 !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1600)
32# define _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS 1
33#else
34# define _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS 0
35#endif
36
37#if _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS && !defined(__OPTIMIZE_SIZE__)
38# define _LIBCPP_VECTORIZE_ALGORITHMS 1
39#else
40# define _LIBCPP_VECTORIZE_ALGORITHMS 0
41#endif
42
43#if _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS
44
45_LIBCPP_BEGIN_NAMESPACE_STD
46
47template <class _Tp>
48inline constexpr bool __can_map_to_integer_v =
49 sizeof(_Tp) == alignof(_Tp) && (sizeof(_Tp) == 1 || sizeof(_Tp) == 2 || sizeof(_Tp) == 4 || sizeof(_Tp) == 8);
50
51template <size_t _TypeSize>
52struct __get_as_integer_type_impl;
53
54template <>
55struct __get_as_integer_type_impl<1> {
56 using type _LIBCPP_NODEBUG = uint8_t;
57};
58
59template <>
60struct __get_as_integer_type_impl<2> {
61 using type _LIBCPP_NODEBUG = uint16_t;
62};
63template <>
64struct __get_as_integer_type_impl<4> {
65 using type _LIBCPP_NODEBUG = uint32_t;
66};
67template <>
68struct __get_as_integer_type_impl<8> {
69 using type _LIBCPP_NODEBUG = uint64_t;
70};
71
72template <class _Tp>
73using __get_as_integer_type_t _LIBCPP_NODEBUG = typename __get_as_integer_type_impl<sizeof(_Tp)>::type;
74
75// This isn't specialized for 64 byte vectors on purpose. They have the potential to significantly reduce performance
76// in mixed simd/non-simd workloads and don't provide any performance improvement for currently vectorized algorithms
77// as far as benchmarks are concerned.
78# if defined(__AVX__) || defined(__MVS__)
79template <class _Tp>
80inline constexpr size_t __native_vector_size = 32 / sizeof(_Tp);
81# elif defined(__SSE__) || defined(__ARM_NEON)
82template <class _Tp>
83inline constexpr size_t __native_vector_size = 16 / sizeof(_Tp);
84# elif defined(__MMX__)
85template <class _Tp>
86inline constexpr size_t __native_vector_size = 8 / sizeof(_Tp);
87# else
88template <class _Tp>
89inline constexpr size_t __native_vector_size = 1;
90# endif
91
92template <class _ArithmeticT, size_t _Np>
93using __simd_vector __attribute__((__ext_vector_type__(_Np))) _LIBCPP_NODEBUG = _ArithmeticT;
94
95template <class _VecT>
96inline constexpr size_t __simd_vector_size_v = []<bool _False = false>() -> size_t {
97 static_assert(_False, "Not a vector!");
98}();
99
100template <class _Tp, size_t _Np>
101inline constexpr size_t __simd_vector_size_v<__simd_vector<_Tp, _Np>> = _Np;
102
103template <class _Tp, size_t _Np>
104_LIBCPP_HIDE_FROM_ABI _Tp __simd_vector_underlying_type_impl(__simd_vector<_Tp, _Np>) {
105 return _Tp{};
106}
107
108template <class _VecT>
109using __simd_vector_underlying_type_t _LIBCPP_NODEBUG = decltype(std::__simd_vector_underlying_type_impl(_VecT{}));
110
111// This isn't inlined without always_inline when loading chars.
112template <class _VecT, class _Iter>
113[[__nodiscard__]] _LIBCPP_ALWAYS_INLINE _LIBCPP_HIDE_FROM_ABI _VecT __load_vector(_Iter __iter) noexcept {
114 return [=]<size_t... _Indices>(index_sequence<_Indices...>) _LIBCPP_ALWAYS_INLINE noexcept {
115 return _VecT{__iter[_Indices]...};
116 }(make_index_sequence<__simd_vector_size_v<_VecT>>{});
117}
118
119template <class _Tp, size_t _Np>
120[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool __all_of(__simd_vector<_Tp, _Np> __vec) noexcept {
121 return __builtin_reduce_and(__builtin_convertvector(__vec, __simd_vector<bool, _Np>));
122}
123
124template <class _Tp, size_t _Np>
125[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_t __find_first_set(__simd_vector<_Tp, _Np> __vec) noexcept {
126 using __mask_vec = __simd_vector<bool, _Np>;
127
128 // This has MSan disabled du to https://github.com/llvm/llvm-project/issues/85876
129 auto __impl = [&]<class _MaskT>(_MaskT) _LIBCPP_NO_SANITIZE("memory") noexcept {
130# if defined(_LIBCPP_BIG_ENDIAN)
131 return std::min<size_t>(
132 _Np, std::__countl_zero(__builtin_bit_cast(_MaskT, __builtin_convertvector(__vec, __mask_vec))));
133# else
134 return std::min<size_t>(
135 _Np, std::__countr_zero(__builtin_bit_cast(_MaskT, __builtin_convertvector(__vec, __mask_vec))));
136# endif
137 };
138
139 if constexpr (sizeof(__mask_vec) == sizeof(uint8_t)) {
140 return __impl(uint8_t{});
141 } else if constexpr (sizeof(__mask_vec) == sizeof(uint16_t)) {
142 return __impl(uint16_t{});
143 } else if constexpr (sizeof(__mask_vec) == sizeof(uint32_t)) {
144 return __impl(uint32_t{});
145 } else if constexpr (sizeof(__mask_vec) == sizeof(uint64_t)) {
146 return __impl(uint64_t{});
147 } else {
148 static_assert(sizeof(__mask_vec) == 0, "unexpected required size for mask integer type");
149 return 0;
150 }
151}
152
153template <class _Tp, size_t _Np>
154[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_t __find_first_not_set(__simd_vector<_Tp, _Np> __vec) noexcept {
155 return std::__find_first_set(~__vec);
156}
157
158_LIBCPP_END_NAMESPACE_STD
159
160#endif // _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS
161
162_LIBCPP_POP_MACROS
163
164#endif // _LIBCPP___ALGORITHM_SIMD_UTILS_H