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
22int main(int argc, char** argv) {
23 auto std_copy_if = [](auto first, auto last, auto out, auto pred) { return std::copy_if(first, last, out, pred); };
24
25 // Benchmark {std,ranges}::copy_if where we copy one out of two element, in alternance.
26 // This is basically the worst case for this algorithm, I don't think there are many
27 // optimizations that can be applied in this case.
28 {
29 auto bm = []<class Container>(std::string name, auto copy_if) {
30 benchmark::RegisterBenchmark(name, [copy_if](auto& st) {
31 std::size_t const n = st.range(0);
32 using ValueType = typename Container::value_type;
33 Container c;
34 std::generate_n(std::back_inserter(c), n, [] { return Generate<ValueType>::random(); });
35
36 std::vector<ValueType> out(n);
37
38 for ([[maybe_unused]] auto _ : st) {
39 bool do_copy = false;
40 auto pred = [&do_copy](auto& element) {
41 benchmark::DoNotOptimize(element);
42 do_copy = !do_copy;
43 return do_copy;
44 };
45 benchmark::DoNotOptimize(c);
46 benchmark::DoNotOptimize(out);
47 auto result = copy_if(c.begin(), c.end(), out.begin(), pred);
48 benchmark::DoNotOptimize(result);
49 }
50 })->Range(8, 1 << 20);
51 };
52 bm.operator()<std::vector<int>>(name: "std::copy_if(vector<int>) (every other)", copy_if: std_copy_if);
53 bm.operator()<std::deque<int>>(name: "std::copy_if(deque<int>) (every other)", copy_if: std_copy_if);
54 bm.operator()<std::list<int>>(name: "std::copy_if(list<int>) (every other)", copy_if: std_copy_if);
55
56 bm.operator()<std::vector<int>>("rng::copy_if(vector<int>) (every other)", std::ranges::copy_if);
57 bm.operator()<std::deque<int>>("rng::copy_if(deque<int>) (every other)", std::ranges::copy_if);
58 bm.operator()<std::list<int>>("rng::copy_if(list<int>) (every other)", std::ranges::copy_if);
59 }
60
61 // Benchmark {std,ranges}::copy_if where we copy the full range.
62 // Copy the full range.
63 {
64 auto bm = []<class Container>(std::string name, auto copy_if) {
65 benchmark::RegisterBenchmark(name, [copy_if](auto& st) {
66 std::size_t const n = st.range(0);
67 using ValueType = typename Container::value_type;
68 Container c;
69 std::generate_n(std::back_inserter(c), n, [] { return Generate<ValueType>::random(); });
70
71 std::vector<ValueType> out(n);
72
73 for ([[maybe_unused]] auto _ : st) {
74 auto pred = [](auto& element) {
75 benchmark::DoNotOptimize(element);
76 return true;
77 };
78 benchmark::DoNotOptimize(c);
79 benchmark::DoNotOptimize(out);
80 auto result = copy_if(c.begin(), c.end(), out.begin(), pred);
81 benchmark::DoNotOptimize(result);
82 }
83 })->Range(8, 1 << 20);
84 };
85 bm.operator()<std::vector<int>>(name: "std::copy_if(vector<int>) (entire range)", copy_if: std_copy_if);
86 bm.operator()<std::deque<int>>(name: "std::copy_if(deque<int>) (entire range)", copy_if: std_copy_if);
87 bm.operator()<std::list<int>>(name: "std::copy_if(list<int>) (entire range)", copy_if: std_copy_if);
88
89 bm.operator()<std::vector<int>>("rng::copy_if(vector<int>) (entire range)", std::ranges::copy_if);
90 bm.operator()<std::deque<int>>("rng::copy_if(deque<int>) (entire range)", std::ranges::copy_if);
91 bm.operator()<std::list<int>>("rng::copy_if(list<int>) (entire range)", std::ranges::copy_if);
92 }
93
94 benchmark::Initialize(&argc, argv);
95 benchmark::RunSpecifiedBenchmarks();
96 benchmark::Shutdown();
97 return 0;
98}
99

source code of libcxx/test/benchmarks/algorithms/modifying/copy_if.bench.cpp