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// UNSUPPORTED: c++03, c++11, c++14, c++17
10
11#include <algorithm>
12#include <cstddef>
13#include <deque>
14#include <iterator>
15#include <list>
16#include <string>
17#include <vector>
18
19#include "benchmark/benchmark.h"
20#include "../../GenerateInput.h"
21
22auto compute_median(auto first, auto last) {
23 std::vector v(first, last);
24 auto middle = v.begin() + v.size() / 2;
25 std::nth_element(v.begin(), middle, v.end());
26 return *middle;
27}
28
29int main(int argc, char** argv) {
30 auto std_partition_copy = [](auto first, auto last, auto out_yes, auto out_no, auto pred) {
31 return std::partition_copy(first, last, out_yes, out_no, pred);
32 };
33
34 auto bm = []<class Container>(std::string name, auto partition_copy) {
35 benchmark::RegisterBenchmark(
36 name,
37 [partition_copy](auto& st) {
38 std::size_t const size = st.range(0);
39 using ValueType = typename Container::value_type;
40 Container c;
41 std::generate_n(std::back_inserter(c), size, [] { return Generate<ValueType>::random(); });
42
43 std::vector<ValueType> yes(size);
44 std::vector<ValueType> no(size);
45 ValueType median = compute_median(c.begin(), c.end());
46 auto pred = [median](auto const& element) { return element < median; };
47
48 for ([[maybe_unused]] auto _ : st) {
49 benchmark::DoNotOptimize(c);
50 benchmark::DoNotOptimize(yes);
51 benchmark::DoNotOptimize(no);
52 auto result = partition_copy(c.begin(), c.end(), yes.begin(), no.begin(), pred);
53 benchmark::DoNotOptimize(result);
54 }
55 })
56 ->Arg(32)
57 ->Arg(50) // non power-of-two
58 ->Arg(1024)
59 ->Arg(8192);
60 };
61
62 // std::partition_copy
63 bm.operator()<std::vector<int>>(name: "std::partition_copy(vector<int>)", partition_copy: std_partition_copy);
64 bm.operator()<std::deque<int>>(name: "std::partition_copy(deque<int>)", partition_copy: std_partition_copy);
65 bm.operator()<std::list<int>>(name: "std::partition_copy(list<int>)", partition_copy: std_partition_copy);
66
67 // ranges::partition_copy
68 bm.operator()<std::vector<int>>("rng::partition_copy(vector<int>)", std::ranges::partition_copy);
69 bm.operator()<std::deque<int>>("rng::partition_copy(deque<int>)", std::ranges::partition_copy);
70 bm.operator()<std::list<int>>("rng::partition_copy(list<int>)", std::ranges::partition_copy);
71
72 benchmark::Initialize(&argc, argv);
73 benchmark::RunSpecifiedBenchmarks();
74 benchmark::Shutdown();
75 return 0;
76}
77

source code of libcxx/test/benchmarks/algorithms/partitions/partition_copy.bench.cpp