xref: /freebsd/contrib/llvm-project/libcxx/include/__pstl/cpu_algos/for_each.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
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___PSTL_CPU_ALGOS_FOR_EACH_H
10 #define _LIBCPP___PSTL_CPU_ALGOS_FOR_EACH_H
11 
12 #include <__algorithm/for_each.h>
13 #include <__assert>
14 #include <__config>
15 #include <__iterator/concepts.h>
16 #include <__pstl/backend_fwd.h>
17 #include <__pstl/cpu_algos/cpu_traits.h>
18 #include <__type_traits/is_execution_policy.h>
19 #include <__utility/empty.h>
20 #include <optional>
21 
22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23 #  pragma GCC system_header
24 #endif
25 
26 _LIBCPP_BEGIN_NAMESPACE_STD
27 namespace __pstl {
28 
29 template <class _Iterator, class _DifferenceType, class _Function>
__simd_for_each(_Iterator __first,_DifferenceType __n,_Function __f)30 _LIBCPP_HIDE_FROM_ABI _Iterator __simd_for_each(_Iterator __first, _DifferenceType __n, _Function __f) noexcept {
31   _PSTL_PRAGMA_SIMD
32   for (_DifferenceType __i = 0; __i < __n; ++__i)
33     __f(__first[__i]);
34 
35   return __first + __n;
36 }
37 
38 template <class _Backend, class _RawExecutionPolicy>
39 struct __cpu_parallel_for_each {
40   template <class _Policy, class _ForwardIterator, class _Function>
41   _LIBCPP_HIDE_FROM_ABI optional<__empty>
operator__cpu_parallel_for_each42   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Function __func) const noexcept {
43     if constexpr (__is_parallel_execution_policy_v<_RawExecutionPolicy> &&
44                   __has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
45       return __cpu_traits<_Backend>::__for_each(
46           __first, __last, [&__policy, __func](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
47             using _ForEachUnseq = __pstl::__for_each<_Backend, __remove_parallel_policy_t<_RawExecutionPolicy>>;
48             [[maybe_unused]] auto __res =
49                 _ForEachUnseq()(std::__remove_parallel_policy(__policy), __brick_first, __brick_last, __func);
50             _LIBCPP_ASSERT_INTERNAL(__res, "unseq/seq should never try to allocate!");
51           });
52     } else if constexpr (__is_unsequenced_execution_policy_v<_RawExecutionPolicy> &&
53                          __has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
54       __pstl::__simd_for_each(__first, __last - __first, __func);
55       return __empty{};
56     } else {
57       std::for_each(__first, __last, __func);
58       return __empty{};
59     }
60   }
61 };
62 
63 } // namespace __pstl
64 _LIBCPP_END_NAMESPACE_STD
65 
66 #endif // _LIBCPP___PSTL_CPU_ALGOS_FOR_EACH_H
67