94 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++14, c++1710 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_n = [](auto first, auto n, auto f) { return std::for_each_n(first, n, f); };23 24 // {std,ranges}::for_each_n25 {26 auto bm = []<class Container>(std::string name, auto for_each_n) {27 using ElemType = typename Container::value_type;28 benchmark::RegisterBenchmark(29 name,30 [for_each_n](auto& st) {31 std::size_t const n = st.range(0);32 Container c(n, 1);33 auto first = c.begin();34 35 for ([[maybe_unused]] auto _ : st) {36 benchmark::DoNotOptimize(c);37 auto result = for_each_n(first, n, [](ElemType& x) { x = std::clamp<ElemType>(x, 10, 100); });38 benchmark::DoNotOptimize(result);39 }40 })41 ->Arg(8)42 ->Arg(32)43 ->Arg(50) // non power-of-two44 ->Arg(8192);45 };46 bm.operator()<std::vector<int>>("std::for_each_n(vector<int>)", std_for_each_n);47 bm.operator()<std::deque<int>>("std::for_each_n(deque<int>)", std_for_each_n);48 bm.operator()<std::list<int>>("std::for_each_n(list<int>)", std_for_each_n);49 bm.operator()<std::vector<int>>("rng::for_each_n(vector<int>)", std::ranges::for_each_n);50 bm.operator()<std::deque<int>>("rng::for_each_n(deque<int>)", std::ranges::for_each_n);51 bm.operator()<std::list<int>>("rng::for_each_n(list<int>)", std::ranges::for_each_n);52 }53 54 // {std,ranges}::for_each_n for join_view55 {56 auto bm = []<class Container>(std::string name, auto for_each_n) {57 using C1 = typename Container::value_type;58 using ElemType = typename C1::value_type;59 benchmark::RegisterBenchmark(60 name,61 [for_each_n](auto& st) {62 std::size_t const size = st.range(0);63 std::size_t const seg_size = 256;64 std::size_t const segments = (size + seg_size - 1) / seg_size;65 Container c(segments);66 for (std::size_t i = 0, n = size; i < segments; ++i, n -= seg_size) {67 c[i].resize(std::min(seg_size, n), ElemType(1));68 }69 70 auto view = c | std::views::join;71 auto first = view.begin();72 73 for ([[maybe_unused]] auto _ : st) {74 benchmark::DoNotOptimize(c);75 auto result = for_each_n(first, size, [](ElemType& x) { x = std::clamp<ElemType>(x, 10, 100); });76 benchmark::DoNotOptimize(result);77 }78 })79 ->Arg(8)80 ->Arg(32)81 ->Arg(50) // non power-of-two82 ->Arg(8192);83 };84 bm.operator()<std::vector<std::vector<int>>>("std::for_each_n(join_view(vector<vector<int>>))", std_for_each_n);85 bm.operator()<std::vector<std::vector<int>>>(86 "rng::for_each_n(join_view(vector<vector<int>>)", std::ranges::for_each_n);87 }88 89 benchmark::Initialize(&argc, argv);90 benchmark::RunSpecifiedBenchmarks();91 benchmark::Shutdown();92 return 0;93}94