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[libcxx] Added segmented iterator for count_if #105888

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[libcxx] Added segmented iterator for count_if #105888

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7e47590
[libcxx] Added segmented iterator for count_if
adeel10x Aug 23, 2024
f6e14b3
Added newline at the end of the file
adeel10x Aug 23, 2024
2aee251
[libcxx] Removed separate function templates for input and segmented …
adeel10x Aug 30, 2024
1234b4f
Merge branch 'llvm:main' into main
adeel10x Aug 31, 2024
b6268b0
[libcxx] Added benchmark for count_if algorithm's implemetation for s…
adeel10x Sep 2, 2024
d6842c2
Merge remote-tracking branch 'refs/remotes/origin/main'
adeel10x Sep 2, 2024
7b2ce11
[libc++] Changed parameter type of lambda to 'const auto&' and remove…
adeel10x Sep 3, 2024
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32 changes: 29 additions & 3 deletions libcxx/include/__algorithm/count_if.h
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Expand Up @@ -10,26 +10,52 @@
#ifndef _LIBCPP___ALGORITHM_COUNT_IF_H
#define _LIBCPP___ALGORITHM_COUNT_IF_H

#include <__algorithm/for_each.h>
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@philnik777 philnik777 Aug 30, 2024

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Not attached: This optimization should also be applied to ranges::count_if.

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@adeel10x adeel10x Sep 5, 2024 •
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@philnik777 I just want to confirm that you mean to say ranges::count_if and not std::count?
Also, Is ranges::for_each optimized for segmented iterators?

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@philnik777 philnik777 Sep 8, 2024

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I don't know whether ranges::for_each is optimized. If not, we should definitely do it.

#include <__config>
#include <__iterator/iterator_traits.h>
#include <__iterator/segmented_iterator.h>
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@philnik777 philnik777 Aug 30, 2024

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Not attached: Please add a benchmark to show that this actually improves performance.


#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _InputIterator, class _Predicate>
template <class _InputIterator,
class _Predicate,
__enable_if_t<!__is_segmented_iterator<_InputIterator>::value, int> = 0>
_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
typename iterator_traits<_InputIterator>::difference_type
count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
typename iterator_traits<_InputIterator>::difference_type
__count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
typename iterator_traits<_InputIterator>::difference_type __r(0);
for (; __first != __last; ++__first)
if (__pred(*__first))
++__r;
return __r;
}

template <class _SegmentedIterator,
class _Predicate,
__enable_if_t<__is_segmented_iterator<_SegmentedIterator>::value, int> = 0>
_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
typename iterator_traits<_SegmentedIterator>::difference_type
__count_if(_SegmentedIterator __first, _SegmentedIterator __last, _Predicate __pred) {
typename iterator_traits<_SegmentedIterator>::difference_type __r(0);
std::for_each(__first, __last, [&__r, __pred](auto& __val) mutable {
if (__pred(__val))
++__r;
});
return __r;
}

template <class _InputIterator, class _Predicate>
_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
typename iterator_traits<_InputIterator>::difference_type
count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
return __count_if(__first, __last, __pred);
}

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___ALGORITHM_COUNT_IF_H