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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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10 changes: 6 additions & 4 deletions libcxx/include/__algorithm/count_if.h
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Expand Up @@ -10,6 +10,7 @@
#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>

Expand All @@ -21,12 +22,13 @@ _LIBCPP_BEGIN_NAMESPACE_STD

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) {
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))
std::for_each(__first, __last, [&__r, &__pred](const auto& __val) mutable {
if (__pred(__val))
++__r;
});
return __r;
}

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1 change: 1 addition & 0 deletions libcxx/test/benchmarks/CMakeLists.txt
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Expand Up @@ -110,6 +110,7 @@ endfunction()
set(BENCHMARK_TESTS
algorithms.partition_point.bench.cpp
algorithms/count.bench.cpp
algorithms/count_if.bench.cpp
algorithms/equal.bench.cpp
algorithms/find.bench.cpp
algorithms/fill.bench.cpp
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22 changes: 22 additions & 0 deletions libcxx/test/benchmarks/algorithms/count_if.bench.cpp
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@@ -0,0 +1,22 @@
//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include <algorithm>
#include <benchmark/benchmark.h>
#include <deque>

static void bm_deque_count_if(benchmark::State& state) {
std::deque<char> deque1(state.range(), '1');
for (auto _ : state) {
benchmark::DoNotOptimize(deque1);
benchmark::DoNotOptimize(std::count_if(deque1.begin(), deque1.end(), [](char& v) { return v == '0'; }));
}
}
BENCHMARK(bm_deque_count_if)->DenseRange(1, 8)->Range(16, 1 << 20);

BENCHMARK_MAIN();