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 <list>
15#include <ranges>
16#include <string>
17#include <vector>
18
19#include <benchmark/benchmark.h>
20
21int main(int argc, char** argv) {
22 auto std_for_each = [](auto first, auto last, auto f) { return std::for_each(first, last, f); };
23
24 // {std,ranges}::for_each
25 {
26 auto bm = []<class Container>(std::string name, auto for_each) {
27 using ElemType = typename Container::value_type;
28 benchmark::RegisterBenchmark(
29 name,
30 [for_each](auto& st) {
31 std::size_t const size = st.range(0);
32 Container c(size, 1);
33 auto first = c.begin();
34 auto last = c.end();
35
36 for ([[maybe_unused]] auto _ : st) {
37 benchmark::DoNotOptimize(c);
38 auto result = for_each(first, last, [](ElemType& x) { x = std::clamp<ElemType>(x, 10, 100); });
39 benchmark::DoNotOptimize(result);
40 }
41 })
42 ->Arg(8)
43 ->Arg(32)
44 ->Arg(50) // non power-of-two
45 ->Arg(8192);
46 };
47 bm.operator()<std::vector<int>>("std::for_each(vector<int>)", std_for_each);
48 bm.operator()<std::deque<int>>("std::for_each(deque<int>)", std_for_each);
49 bm.operator()<std::list<int>>("std::for_each(list<int>)", std_for_each);
50 bm.operator()<std::vector<int>>("rng::for_each(vector<int>)", std::ranges::for_each);
51 bm.operator()<std::deque<int>>("rng::for_each(deque<int>)", std::ranges::for_each);
52 bm.operator()<std::list<int>>("rng::for_each(list<int>)", std::ranges::for_each);
53 }
54
55 // {std,ranges}::for_each for join_view
56 {
57 auto bm = []<class Container>(std::string name, auto for_each) {
58 using C1 = typename Container::value_type;
59 using ElemType = typename C1::value_type;
60
61 benchmark::RegisterBenchmark(
62 name,
63 [for_each](auto& st) {
64 std::size_t const size = st.range(0);
65 std::size_t const seg_size = 256;
66 std::size_t const segments = (size + seg_size - 1) / seg_size;
67 Container c(segments);
68 for (std::size_t i = 0, n = size; i < segments; ++i, n -= seg_size) {
69 c[i].resize(std::min(seg_size, n), ElemType(1));
70 }
71
72 auto view = c | std::views::join;
73 auto first = view.begin();
74 auto last = view.end();
75
76 for ([[maybe_unused]] auto _ : st) {
77 benchmark::DoNotOptimize(c);
78 auto result = for_each(first, last, [](ElemType& x) { x = std::clamp<ElemType>(x, 10, 100); });
79 benchmark::DoNotOptimize(result);
80 }
81 })
82 ->Arg(8)
83 ->Arg(32)
84 ->Arg(50) // non power-of-two
85 ->Arg(8192);
86 };
87 bm.operator()<std::vector<std::vector<int>>>("std::for_each(join_view(vector<vector<int>>))", std_for_each);
88 bm.operator()<std::vector<std::vector<int>>>("rng::for_each(join_view(vector<vector<int>>)", std::ranges::for_each);
89 }
90
91 benchmark::Initialize(&argc, argv);
92 benchmark::RunSpecifiedBenchmarks();
93 benchmark::Shutdown();
94 return 0;
95}
96

source code of libcxx/test/benchmarks/algorithms/nonmodifying/for_each.bench.cpp