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nativity/lib/libcxx/include/__pstl/internal/unseq_backend_simd.h
David Gonzalez Martin f7e0435931 Add libcxx and libunwind
2024-03-24 17:47:27 -06:00

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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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 _PSTL_UNSEQ_BACKEND_SIMD_H
#define _PSTL_UNSEQ_BACKEND_SIMD_H
#include <__config>
#include <__functional/operations.h>
#include <__iterator/iterator_traits.h>
#include <__type_traits/is_arithmetic.h>
#include <__type_traits/is_same.h>
#include <__utility/move.h>
#include <__utility/pair.h>
#include <cstddef>
#include <cstdint>
#include <__pstl/internal/utils.h>
// This header defines the minimum set of vector routines required
// to support parallel STL.
#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
namespace __pstl
{
namespace __unseq_backend
{
// Expect vector width up to 64 (or 512 bit)
const std::size_t __lane_size = 64;
template <class _Iterator, class _DifferenceType, class _Function>
_LIBCPP_HIDE_FROM_ABI _Iterator
__simd_walk_1(_Iterator __first, _DifferenceType __n, _Function __f) noexcept
{
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
__f(__first[__i]);
return __first + __n;
}
template <class _Iterator1, class _DifferenceType, class _Iterator2, class _Function>
_LIBCPP_HIDE_FROM_ABI _Iterator2
__simd_walk_2(_Iterator1 __first1, _DifferenceType __n, _Iterator2 __first2, _Function __f) noexcept
{
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
__f(__first1[__i], __first2[__i]);
return __first2 + __n;
}
template <class _Iterator1, class _DifferenceType, class _Iterator2, class _Iterator3, class _Function>
_LIBCPP_HIDE_FROM_ABI _Iterator3
__simd_walk_3(_Iterator1 __first1, _DifferenceType __n, _Iterator2 __first2, _Iterator3 __first3,
_Function __f) noexcept
{
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
__f(__first1[__i], __first2[__i], __first3[__i]);
return __first3 + __n;
}
// TODO: check whether __simd_first() can be used here
template <class _Index, class _DifferenceType, class _Pred>
_LIBCPP_HIDE_FROM_ABI bool
__simd_or(_Index __first, _DifferenceType __n, _Pred __pred) noexcept
{
_DifferenceType __block_size = 4 < __n ? 4 : __n;
const _Index __last = __first + __n;
while (__last != __first)
{
int32_t __flag = 1;
_PSTL_PRAGMA_SIMD_REDUCTION(& : __flag)
for (_DifferenceType __i = 0; __i < __block_size; ++__i)
if (__pred(*(__first + __i)))
__flag = 0;
if (!__flag)
return true;
__first += __block_size;
if (__last - __first >= __block_size << 1)
{
// Double the block _Size. Any unnecessary iterations can be amortized against work done so far.
__block_size <<= 1;
}
else
{
__block_size = __last - __first;
}
}
return false;
}
template <class _Index1, class _DifferenceType, class _Index2, class _Pred>
_LIBCPP_HIDE_FROM_ABI std::pair<_Index1, _Index2>
__simd_first(_Index1 __first1, _DifferenceType __n, _Index2 __first2, _Pred __pred) noexcept
{
const _Index1 __last1 = __first1 + __n;
const _Index2 __last2 = __first2 + __n;
// Experiments show good block sizes like this
const _DifferenceType __block_size = 8;
alignas(__lane_size) _DifferenceType __lane[__block_size] = {0};
while (__last1 - __first1 >= __block_size)
{
_DifferenceType __found = 0;
_DifferenceType __i;
_PSTL_PRAGMA_SIMD_REDUCTION(|
: __found) for (__i = 0; __i < __block_size; ++__i)
{
const _DifferenceType __t = __pred(__first1[__i], __first2[__i]);
__lane[__i] = __t;
__found |= __t;
}
if (__found)
{
_DifferenceType __i2;
// This will vectorize
for (__i2 = 0; __i2 < __block_size; ++__i2)
{
if (__lane[__i2])
break;
}
return std::make_pair(__first1 + __i2, __first2 + __i2);
}
__first1 += __block_size;
__first2 += __block_size;
}
//Keep remainder scalar
for (; __last1 != __first1; ++__first1, ++__first2)
if (__pred(*(__first1), *(__first2)))
return std::make_pair(__first1, __first2);
return std::make_pair(__last1, __last2);
}
template <class _Index, class _DifferenceType, class _Pred>
_LIBCPP_HIDE_FROM_ABI _DifferenceType
__simd_count(_Index __index, _DifferenceType __n, _Pred __pred) noexcept
{
_DifferenceType __count = 0;
_PSTL_PRAGMA_SIMD_REDUCTION(+ : __count)
for (_DifferenceType __i = 0; __i < __n; ++__i)
if (__pred(*(__index + __i)))
++__count;
return __count;
}
template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _BinaryPredicate>
_LIBCPP_HIDE_FROM_ABI _OutputIterator
__simd_unique_copy(_InputIterator __first, _DifferenceType __n, _OutputIterator __result,
_BinaryPredicate __pred) noexcept
{
if (__n == 0)
return __result;
_DifferenceType __cnt = 1;
__result[0] = __first[0];
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 1; __i < __n; ++__i)
{
if (!__pred(__first[__i], __first[__i - 1]))
{
__result[__cnt] = __first[__i];
++__cnt;
}
}
return __result + __cnt;
}
template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _Assigner>
_LIBCPP_HIDE_FROM_ABI _OutputIterator
__simd_assign(_InputIterator __first, _DifferenceType __n, _OutputIterator __result, _Assigner __assigner) noexcept
{
_PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
__assigner(__first + __i, __result + __i);
return __result + __n;
}
template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _UnaryPredicate>
_LIBCPP_HIDE_FROM_ABI _OutputIterator
__simd_copy_if(_InputIterator __first, _DifferenceType __n, _OutputIterator __result, _UnaryPredicate __pred) noexcept
{
_DifferenceType __cnt = 0;
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
{
if (__pred(__first[__i]))
{
__result[__cnt] = __first[__i];
++__cnt;
}
}
return __result + __cnt;
}
template <class _InputIterator, class _DifferenceType, class _BinaryPredicate>
_LIBCPP_HIDE_FROM_ABI _DifferenceType
__simd_calc_mask_2(_InputIterator __first, _DifferenceType __n, bool* __mask, _BinaryPredicate __pred) noexcept
{
_DifferenceType __count = 0;
_PSTL_PRAGMA_SIMD_REDUCTION(+ : __count)
for (_DifferenceType __i = 0; __i < __n; ++__i)
{
__mask[__i] = !__pred(__first[__i], __first[__i - 1]);
__count += __mask[__i];
}
return __count;
}
template <class _InputIterator, class _DifferenceType, class _UnaryPredicate>
_LIBCPP_HIDE_FROM_ABI _DifferenceType
__simd_calc_mask_1(_InputIterator __first, _DifferenceType __n, bool* __mask, _UnaryPredicate __pred) noexcept
{
_DifferenceType __count = 0;
_PSTL_PRAGMA_SIMD_REDUCTION(+ : __count)
for (_DifferenceType __i = 0; __i < __n; ++__i)
{
__mask[__i] = __pred(__first[__i]);
__count += __mask[__i];
}
return __count;
}
template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _Assigner>
_LIBCPP_HIDE_FROM_ABI void
__simd_copy_by_mask(_InputIterator __first, _DifferenceType __n, _OutputIterator __result, bool* __mask,
_Assigner __assigner) noexcept
{
_DifferenceType __cnt = 0;
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
{
if (__mask[__i])
{
{
__assigner(__first + __i, __result + __cnt);
++__cnt;
}
}
}
}
template <class _InputIterator, class _DifferenceType, class _OutputIterator1, class _OutputIterator2>
_LIBCPP_HIDE_FROM_ABI void
__simd_partition_by_mask(_InputIterator __first, _DifferenceType __n, _OutputIterator1 __out_true,
_OutputIterator2 __out_false, bool* __mask) noexcept
{
_DifferenceType __cnt_true = 0, __cnt_false = 0;
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
{
if (__mask[__i])
{
__out_true[__cnt_true] = __first[__i];
++__cnt_true;
}
else
{
__out_false[__cnt_false] = __first[__i];
++__cnt_false;
}
}
}
template <class _Index, class _DifferenceType, class _Generator>
_LIBCPP_HIDE_FROM_ABI _Index
__simd_generate_n(_Index __first, _DifferenceType __size, _Generator __g) noexcept
{
_PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __size; ++__i)
__first[__i] = __g();
return __first + __size;
}
template <class _Index, class _BinaryPredicate>
_LIBCPP_HIDE_FROM_ABI _Index
__simd_adjacent_find(_Index __first, _Index __last, _BinaryPredicate __pred, bool __or_semantic) noexcept
{
if (__last - __first < 2)
return __last;
typedef typename std::iterator_traits<_Index>::difference_type _DifferenceType;
_DifferenceType __i = 0;
// Experiments show good block sizes like this
//TODO: to consider tuning block_size for various data types
const _DifferenceType __block_size = 8;
alignas(__lane_size) _DifferenceType __lane[__block_size] = {0};
while (__last - __first >= __block_size)
{
_DifferenceType __found = 0;
_PSTL_PRAGMA_SIMD_REDUCTION(|
: __found) for (__i = 0; __i < __block_size - 1; ++__i)
{
//TODO: to improve SIMD vectorization
const _DifferenceType __t = __pred(*(__first + __i), *(__first + __i + 1));
__lane[__i] = __t;
__found |= __t;
}
//Process a pair of elements on a boundary of a data block
if (__first + __block_size < __last && __pred(*(__first + __i), *(__first + __i + 1)))
__lane[__i] = __found = 1;
if (__found)
{
if (__or_semantic)
return __first;
// This will vectorize
for (__i = 0; __i < __block_size; ++__i)
if (__lane[__i])
break;
return __first + __i; //As far as found is true a __result (__lane[__i] is true) is guaranteed
}
__first += __block_size;
}
//Process the rest elements
for (; __last - __first > 1; ++__first)
if (__pred(*__first, *(__first + 1)))
return __first;
return __last;
}
// It was created to reduce the code inside std::enable_if
template <typename _Tp, typename _BinaryOperation>
using is_arithmetic_plus = std::integral_constant<bool, std::is_arithmetic<_Tp>::value &&
std::is_same<_BinaryOperation, std::plus<_Tp>>::value>;
// Exclusive scan for "+" and arithmetic types
template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
class _BinaryOperation>
_LIBCPP_HIDE_FROM_ABI
typename std::enable_if<is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
_BinaryOperation, /*Inclusive*/ std::false_type)
{
_PSTL_PRAGMA_SIMD_SCAN(+ : __init)
for (_Size __i = 0; __i < __n; ++__i)
{
__result[__i] = __init;
_PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(__init)
__init += __unary_op(__first[__i]);
}
return std::make_pair(__result + __n, __init);
}
// As soon as we cannot call __binary_op in "combiner" we create a wrapper over _Tp to encapsulate __binary_op
template <typename _Tp, typename _BinaryOp>
struct _Combiner
{
_Tp __value_;
_BinaryOp* __bin_op_; // Here is a pointer to function because of default ctor
_LIBCPP_HIDE_FROM_ABI _Combiner() : __value_{}, __bin_op_(nullptr) {}
_LIBCPP_HIDE_FROM_ABI
_Combiner(const _Tp& __value, const _BinaryOp* __bin_op)
: __value_(__value), __bin_op_(const_cast<_BinaryOp*>(__bin_op)) {}
_LIBCPP_HIDE_FROM_ABI _Combiner(const _Combiner& __obj) : __value_{}, __bin_op_(__obj.__bin_op) {}
_LIBCPP_HIDE_FROM_ABI void
operator()(const _Combiner& __obj)
{
__value_ = (*__bin_op_)(__value_, __obj.__value_);
}
};
// Exclusive scan for other binary operations and types
template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
class _BinaryOperation>
_LIBCPP_HIDE_FROM_ABI
typename std::enable_if<!is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
_BinaryOperation __binary_op, /*Inclusive*/ std::false_type)
{
typedef _Combiner<_Tp, _BinaryOperation> _CombinerType;
_CombinerType __combined_init{__init, &__binary_op};
_PSTL_PRAGMA_DECLARE_REDUCTION(__bin_op, _CombinerType)
_PSTL_PRAGMA_SIMD_SCAN(__bin_op : __combined_init)
for (_Size __i = 0; __i < __n; ++__i)
{
__result[__i] = __combined_init.__value_;
_PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(__combined_init)
__combined_init.__value_ = __binary_op(__combined_init.__value_, __unary_op(__first[__i]));
}
return std::make_pair(__result + __n, __combined_init.__value_);
}
// Inclusive scan for "+" and arithmetic types
template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
class _BinaryOperation>
_LIBCPP_HIDE_FROM_ABI
typename std::enable_if<is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
_BinaryOperation, /*Inclusive*/ std::true_type)
{
_PSTL_PRAGMA_SIMD_SCAN(+ : __init)
for (_Size __i = 0; __i < __n; ++__i)
{
__init += __unary_op(__first[__i]);
_PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(__init)
__result[__i] = __init;
}
return std::make_pair(__result + __n, __init);
}
// Inclusive scan for other binary operations and types
template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
class _BinaryOperation>
_LIBCPP_HIDE_FROM_ABI
typename std::enable_if<!is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
_BinaryOperation __binary_op, std::true_type)
{
typedef _Combiner<_Tp, _BinaryOperation> _CombinerType;
_CombinerType __combined_init{__init, &__binary_op};
_PSTL_PRAGMA_DECLARE_REDUCTION(__bin_op, _CombinerType)
_PSTL_PRAGMA_SIMD_SCAN(__bin_op : __combined_init)
for (_Size __i = 0; __i < __n; ++__i)
{
__combined_init.__value_ = __binary_op(__combined_init.__value_, __unary_op(__first[__i]));
_PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(__combined_init)
__result[__i] = __combined_init.__value_;
}
return std::make_pair(__result + __n, __combined_init.__value_);
}
// [restriction] - std::iterator_traits<_ForwardIterator>::value_type should be DefaultConstructible.
// complexity [violation] - We will have at most (__n-1 + number_of_lanes) comparisons instead of at most __n-1.
template <typename _ForwardIterator, typename _Size, typename _Compare>
_LIBCPP_HIDE_FROM_ABI _ForwardIterator
__simd_min_element(_ForwardIterator __first, _Size __n, _Compare __comp) noexcept
{
if (__n == 0)
{
return __first;
}
typedef typename std::iterator_traits<_ForwardIterator>::value_type _ValueType;
struct _ComplexType
{
_ValueType __min_val_;
_Size __min_ind_;
_Compare* __min_comp_;
_LIBCPP_HIDE_FROM_ABI _ComplexType() : __min_val_{}, __min_ind_{}, __min_comp_(nullptr) {}
_LIBCPP_HIDE_FROM_ABI _ComplexType(const _ValueType& __val, const _Compare* __comp)
: __min_val_(__val), __min_ind_(0), __min_comp_(const_cast<_Compare*>(__comp))
{
}
_LIBCPP_HIDE_FROM_ABI _ComplexType(const _ComplexType& __obj)
: __min_val_(__obj.__min_val_), __min_ind_(__obj.__min_ind_), __min_comp_(__obj.__min_comp_)
{
}
_PSTL_PRAGMA_DECLARE_SIMD
_LIBCPP_HIDE_FROM_ABI void
operator()(const _ComplexType& __obj)
{
if (!(*__min_comp_)(__min_val_, __obj.__min_val_) &&
((*__min_comp_)(__obj.__min_val_, __min_val_) || __obj.__min_ind_ - __min_ind_ < 0))
{
__min_val_ = __obj.__min_val_;
__min_ind_ = __obj.__min_ind_;
}
}
};
_ComplexType __init{*__first, &__comp};
_PSTL_PRAGMA_DECLARE_REDUCTION(__min_func, _ComplexType)
_PSTL_PRAGMA_SIMD_REDUCTION(__min_func : __init)
for (_Size __i = 1; __i < __n; ++__i)
{
const _ValueType __min_val = __init.__min_val_;
const _ValueType __current = __first[__i];
if (__comp(__current, __min_val))
{
__init.__min_val_ = __current;
__init.__min_ind_ = __i;
}
}
return __first + __init.__min_ind_;
}
// [restriction] - std::iterator_traits<_ForwardIterator>::value_type should be DefaultConstructible.
// complexity [violation] - We will have at most (2*(__n-1) + 4*number_of_lanes) comparisons instead of at most [1.5*(__n-1)].
template <typename _ForwardIterator, typename _Size, typename _Compare>
_LIBCPP_HIDE_FROM_ABI std::pair<_ForwardIterator, _ForwardIterator>
__simd_minmax_element(_ForwardIterator __first, _Size __n, _Compare __comp) noexcept
{
if (__n == 0)
{
return std::make_pair(__first, __first);
}
typedef typename std::iterator_traits<_ForwardIterator>::value_type _ValueType;
struct _ComplexType
{
_ValueType __min_val_;
_ValueType __max_val_;
_Size __min_ind_;
_Size __max_ind_;
_Compare* __minmax_comp;
_LIBCPP_HIDE_FROM_ABI _ComplexType()
: __min_val_{}, __max_val_{}, __min_ind_{}, __max_ind_{}, __minmax_comp(nullptr) {}
_LIBCPP_HIDE_FROM_ABI _ComplexType(
const _ValueType& __min_val, const _ValueType& __max_val, const _Compare* __comp)
: __min_val_(__min_val), __max_val_(__max_val), __min_ind_(0), __max_ind_(0),
__minmax_comp(const_cast<_Compare*>(__comp))
{
}
_LIBCPP_HIDE_FROM_ABI _ComplexType(const _ComplexType& __obj)
: __min_val_(__obj.__min_val_), __max_val_(__obj.__max_val_), __min_ind_(__obj.__min_ind_),
__max_ind_(__obj.__max_ind_), __minmax_comp(__obj.__minmax_comp)
{
}
_LIBCPP_HIDE_FROM_ABI void
operator()(const _ComplexType& __obj)
{
// min
if ((*__minmax_comp)(__obj.__min_val_, __min_val_))
{
__min_val_ = __obj.__min_val_;
__min_ind_ = __obj.__min_ind_;
}
else if (!(*__minmax_comp)(__min_val_, __obj.__min_val_))
{
__min_val_ = __obj.__min_val_;
__min_ind_ = (__min_ind_ - __obj.__min_ind_ < 0) ? __min_ind_ : __obj.__min_ind_;
}
// max
if ((*__minmax_comp)(__max_val_, __obj.__max_val_))
{
__max_val_ = __obj.__max_val_;
__max_ind_ = __obj.__max_ind_;
}
else if (!(*__minmax_comp)(__obj.__max_val_, __max_val_))
{
__max_val_ = __obj.__max_val_;
__max_ind_ = (__max_ind_ - __obj.__max_ind_ < 0) ? __obj.__max_ind_ : __max_ind_;
}
}
};
_ComplexType __init{*__first, *__first, &__comp};
_PSTL_PRAGMA_DECLARE_REDUCTION(__min_func, _ComplexType);
_PSTL_PRAGMA_SIMD_REDUCTION(__min_func : __init)
for (_Size __i = 1; __i < __n; ++__i)
{
auto __min_val = __init.__min_val_;
auto __max_val = __init.__max_val_;
auto __current = __first + __i;
if (__comp(*__current, __min_val))
{
__init.__min_val_ = *__current;
__init.__min_ind_ = __i;
}
else if (!__comp(*__current, __max_val))
{
__init.__max_val_ = *__current;
__init.__max_ind_ = __i;
}
}
return std::make_pair(__first + __init.__min_ind_, __first + __init.__max_ind_);
}
template <class _InputIterator, class _DifferenceType, class _OutputIterator1, class _OutputIterator2,
class _UnaryPredicate>
_LIBCPP_HIDE_FROM_ABI std::pair<_OutputIterator1, _OutputIterator2>
__simd_partition_copy(_InputIterator __first, _DifferenceType __n, _OutputIterator1 __out_true,
_OutputIterator2 __out_false, _UnaryPredicate __pred) noexcept
{
_DifferenceType __cnt_true = 0, __cnt_false = 0;
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 0; __i < __n; ++__i)
{
if (__pred(__first[__i]))
{
__out_true[__cnt_true] = __first[__i];
++__cnt_true;
}
else
{
__out_false[__cnt_false] = __first[__i];
++__cnt_false;
}
}
return std::make_pair(__out_true + __cnt_true, __out_false + __cnt_false);
}
template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
_LIBCPP_HIDE_FROM_ABI _ForwardIterator1
__simd_find_first_of(_ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
_ForwardIterator2 __s_last, _BinaryPredicate __pred) noexcept
{
typedef typename std::iterator_traits<_ForwardIterator1>::difference_type _DifferencType;
const _DifferencType __n1 = __last - __first;
const _DifferencType __n2 = __s_last - __s_first;
if (__n1 == 0 || __n2 == 0)
{
return __last; // according to the standard
}
// Common case
// If first sequence larger than second then we'll run simd_first with parameters of first sequence.
// Otherwise, vice versa.
if (__n1 < __n2)
{
for (; __first != __last; ++__first)
{
if (__unseq_backend::__simd_or(
__s_first, __n2,
__internal::__equal_value_by_pred<decltype(*__first), _BinaryPredicate>(*__first, __pred)))
{
return __first;
}
}
}
else
{
for (; __s_first != __s_last; ++__s_first)
{
const auto __result = __unseq_backend::__simd_first(
__first, _DifferencType(0), __n1, [__s_first, &__pred](_ForwardIterator1 __it, _DifferencType __i) {
return __pred(__it[__i], *__s_first);
});
if (__result != __last)
{
return __result;
}
}
}
return __last;
}
template <class _RandomAccessIterator, class _DifferenceType, class _UnaryPredicate>
_LIBCPP_HIDE_FROM_ABI _RandomAccessIterator
__simd_remove_if(_RandomAccessIterator __first, _DifferenceType __n, _UnaryPredicate __pred) noexcept
{
// find first element we need to remove
auto __current = __unseq_backend::__simd_first(
__first, _DifferenceType(0), __n,
[&__pred](_RandomAccessIterator __it, _DifferenceType __i) { return __pred(__it[__i]); });
__n -= __current - __first;
// if we have in sequence only one element that pred(__current[1]) != false we can exit the function
if (__n < 2)
{
return __current;
}
_DifferenceType __cnt = 0;
_PSTL_PRAGMA_SIMD
for (_DifferenceType __i = 1; __i < __n; ++__i)
{
if (!__pred(__current[__i]))
{
__current[__cnt] = std::move(__current[__i]);
++__cnt;
}
}
return __current + __cnt;
}
} // namespace __unseq_backend
} // namespace __pstl
#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
#endif /* _PSTL_UNSEQ_BACKEND_SIMD_H */
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