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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___PSTL_CPU_ALGOS_TRANSFORM_REDUCE_H
#define _LIBCPP___PSTL_CPU_ALGOS_TRANSFORM_REDUCE_H
#include <__assert>
#include <__config>
#include <__iterator/concepts.h>
#include <__iterator/iterator_traits.h>
#include <__numeric/transform_reduce.h>
#include <__pstl/backend_fwd.h>
#include <__pstl/cpu_algos/cpu_traits.h>
#include <__type_traits/desugars_to.h>
#include <__type_traits/is_arithmetic.h>
#include <__type_traits/is_execution_policy.h>
#include <__utility/move.h>
#include <cstddef>
#include <new>
#include <optional>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
namespace __pstl {
template <typename _Backend,
typename _DifferenceType,
typename _Tp,
typename _BinaryOperation,
typename _UnaryOperation,
typename _UnaryResult = invoke_result_t<_UnaryOperation, _DifferenceType>,
__enable_if_t<__desugars_to_v<__plus_tag, _BinaryOperation, _Tp, _UnaryResult> && is_arithmetic_v<_Tp> &&
is_arithmetic_v<_UnaryResult>,
int> = 0>
_LIBCPP_HIDE_FROM_ABI _Tp
__simd_transform_reduce(_DifferenceType __n, _Tp __init, _BinaryOperation, _UnaryOperation __f) noexcept {
_PSTL_PRAGMA_SIMD_REDUCTION(+ : __init)
for (_DifferenceType __i = 0; __i < __n; ++__i)
__init += __f(__i);
return __init;
}
template <typename _Backend,
typename _Size,
typename _Tp,
typename _BinaryOperation,
typename _UnaryOperation,
typename _UnaryResult = invoke_result_t<_UnaryOperation, _Size>,
__enable_if_t<!(__desugars_to_v<__plus_tag, _BinaryOperation, _Tp, _UnaryResult> && is_arithmetic_v<_Tp> &&
is_arithmetic_v<_UnaryResult>),
int> = 0>
_LIBCPP_HIDE_FROM_ABI _Tp
__simd_transform_reduce(_Size __n, _Tp __init, _BinaryOperation __binary_op, _UnaryOperation __f) noexcept {
constexpr size_t __lane_size = __cpu_traits<_Backend>::__lane_size;
const _Size __block_size = __lane_size / sizeof(_Tp);
if (__n > 2 * __block_size && __block_size > 1) {
alignas(__lane_size) char __lane_buffer[__lane_size];
_Tp* __lane = reinterpret_cast<_Tp*>(__lane_buffer);
// initializer
_PSTL_PRAGMA_SIMD
for (_Size __i = 0; __i < __block_size; ++__i) {
::new (__lane + __i) _Tp(__binary_op(__f(__i), __f(__block_size + __i)));
}
// main loop
_Size __i = 2 * __block_size;
const _Size __last_iteration = __block_size * (__n / __block_size);
for (; __i < __last_iteration; __i += __block_size) {
_PSTL_PRAGMA_SIMD
for (_Size __j = 0; __j < __block_size; ++__j) {
__lane[__j] = __binary_op(std::move(__lane[__j]), __f(__i + __j));
}
}
// remainder
_PSTL_PRAGMA_SIMD
for (_Size __j = 0; __j < __n - __last_iteration; ++__j) {
__lane[__j] = __binary_op(std::move(__lane[__j]), __f(__last_iteration + __j));
}
// combiner
for (_Size __j = 0; __j < __block_size; ++__j) {
__init = __binary_op(std::move(__init), std::move(__lane[__j]));
}
// destroyer
_PSTL_PRAGMA_SIMD
for (_Size __j = 0; __j < __block_size; ++__j) {
__lane[__j].~_Tp();
}
} else {
for (_Size __i = 0; __i < __n; ++__i) {
__init = __binary_op(std::move(__init), __f(__i));
}
}
return __init;
}
template <class _Backend, class _RawExecutionPolicy>
struct __cpu_parallel_transform_reduce_binary {
template <class _Policy,
class _ForwardIterator1,
class _ForwardIterator2,
class _Tp,
class _BinaryOperation1,
class _BinaryOperation2>
_LIBCPP_HIDE_FROM_ABI optional<_Tp> operator()(
_Policy&& __policy,
_ForwardIterator1 __first1,
_ForwardIterator1 __last1,
_ForwardIterator2 __first2,
_Tp __init,
_BinaryOperation1 __reduce,
_BinaryOperation2 __transform) const noexcept {
if constexpr (__is_parallel_execution_policy_v<_RawExecutionPolicy> &&
__has_random_access_iterator_category_or_concept<_ForwardIterator1>::value &&
__has_random_access_iterator_category_or_concept<_ForwardIterator2>::value) {
return __cpu_traits<_Backend>::__transform_reduce(
__first1,
std::move(__last1),
[__first1, __first2, __transform](_ForwardIterator1 __iter) {
return __transform(*__iter, *(__first2 + (__iter - __first1)));
},
std::move(__init),
std::move(__reduce),
[&__policy, __first1, __first2, __reduce, __transform](
_ForwardIterator1 __brick_first, _ForwardIterator1 __brick_last, _Tp __brick_init) {
using _TransformReduceBinaryUnseq =
__pstl::__transform_reduce_binary<_Backend, __remove_parallel_policy_t<_RawExecutionPolicy>>;
return *_TransformReduceBinaryUnseq()(
std::__remove_parallel_policy(__policy),
__brick_first,
std::move(__brick_last),
__first2 + (__brick_first - __first1),
std::move(__brick_init),
std::move(__reduce),
std::move(__transform));
});
} else if constexpr (__is_unsequenced_execution_policy_v<_RawExecutionPolicy> &&
__has_random_access_iterator_category_or_concept<_ForwardIterator1>::value &&
__has_random_access_iterator_category_or_concept<_ForwardIterator2>::value) {
return __pstl::__simd_transform_reduce<_Backend>(
__last1 - __first1, std::move(__init), std::move(__reduce), [&](__iter_diff_t<_ForwardIterator1> __i) {
return __transform(__first1[__i], __first2[__i]);
});
} else {
return std::transform_reduce(
std::move(__first1),
std::move(__last1),
std::move(__first2),
std::move(__init),
std::move(__reduce),
std::move(__transform));
}
}
};
template <class _Backend, class _RawExecutionPolicy>
struct __cpu_parallel_transform_reduce {
template <class _Policy, class _ForwardIterator, class _Tp, class _BinaryOperation, class _UnaryOperation>
_LIBCPP_HIDE_FROM_ABI optional<_Tp>
operator()(_Policy&& __policy,
_ForwardIterator __first,
_ForwardIterator __last,
_Tp __init,
_BinaryOperation __reduce,
_UnaryOperation __transform) const noexcept {
if constexpr (__is_parallel_execution_policy_v<_RawExecutionPolicy> &&
__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
return __cpu_traits<_Backend>::__transform_reduce(
std::move(__first),
std::move(__last),
[__transform](_ForwardIterator __iter) { return __transform(*__iter); },
std::move(__init),
__reduce,
[&__policy, __transform, __reduce](auto __brick_first, auto __brick_last, _Tp __brick_init) {
using _TransformReduceUnseq =
__pstl::__transform_reduce<_Backend, __remove_parallel_policy_t<_RawExecutionPolicy>>;
auto __res = _TransformReduceUnseq()(
std::__remove_parallel_policy(__policy),
std::move(__brick_first),
std::move(__brick_last),
std::move(__brick_init),
std::move(__reduce),
std::move(__transform));
_LIBCPP_ASSERT_INTERNAL(__res, "unseq/seq should never try to allocate!");
return *std::move(__res);
});
} else if constexpr (__is_unsequenced_execution_policy_v<_RawExecutionPolicy> &&
__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
return __pstl::__simd_transform_reduce<_Backend>(
__last - __first,
std::move(__init),
std::move(__reduce),
[=, &__transform](__iter_diff_t<_ForwardIterator> __i) { return __transform(__first[__i]); });
} else {
return std::transform_reduce(
std::move(__first), std::move(__last), std::move(__init), std::move(__reduce), std::move(__transform));
}
}
};
} // namespace __pstl
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___PSTL_CPU_ALGOS_TRANSFORM_REDUCE_H
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