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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
#include <algorithm>
#include <cstddef>
#include <deque>
#include <list>
#include <ranges>
#include <string>
#include <vector>
#include <benchmark/benchmark.h>
int main(int argc, char** argv) {
auto std_for_each_n = [](auto first, auto n, auto f) { return std::for_each_n(first, n, f); };
// {std,ranges}::for_each_n
{
auto bm = []<class Container>(std::string name, auto for_each_n) {
using ElemType = typename Container::value_type;
benchmark::RegisterBenchmark(
name,
[for_each_n](auto& st) {
std::size_t const n = st.range(0);
Container c(n, 1);
auto first = c.begin();
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(c);
auto result = for_each_n(first, n, [](ElemType& x) { x = std::clamp<ElemType>(x, 10, 100); });
benchmark::DoNotOptimize(result);
}
})
->Arg(8)
->Arg(32)
->Arg(50) // non power-of-two
->Arg(8192);
};
bm.operator()<std::vector<int>>("std::for_each_n(vector<int>)", std_for_each_n);
bm.operator()<std::deque<int>>("std::for_each_n(deque<int>)", std_for_each_n);
bm.operator()<std::list<int>>("std::for_each_n(list<int>)", std_for_each_n);
bm.operator()<std::vector<int>>("rng::for_each_n(vector<int>)", std::ranges::for_each_n);
bm.operator()<std::deque<int>>("rng::for_each_n(deque<int>)", std::ranges::for_each_n);
bm.operator()<std::list<int>>("rng::for_each_n(list<int>)", std::ranges::for_each_n);
}
// {std,ranges}::for_each_n for join_view
{
auto bm = []<class Container>(std::string name, auto for_each_n) {
using C1 = typename Container::value_type;
using ElemType = typename C1::value_type;
benchmark::RegisterBenchmark(
name,
[for_each_n](auto& st) {
std::size_t const size = st.range(0);
std::size_t const seg_size = 256;
std::size_t const segments = (size + seg_size - 1) / seg_size;
Container c(segments);
for (std::size_t i = 0, n = size; i < segments; ++i, n -= seg_size) {
c[i].resize(std::min(seg_size, n), ElemType(1));
}
auto view = c | std::views::join;
auto first = view.begin();
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(c);
auto result = for_each_n(first, size, [](ElemType& x) { x = std::clamp<ElemType>(x, 10, 100); });
benchmark::DoNotOptimize(result);
}
})
->Arg(8)
->Arg(32)
->Arg(50) // non power-of-two
->Arg(8192);
};
bm.operator()<std::vector<std::vector<int>>>("std::for_each_n(join_view(vector<vector<int>>))", std_for_each_n);
bm.operator()<std::vector<std::vector<int>>>(
"rng::for_each_n(join_view(vector<vector<int>>)", std::ranges::for_each_n);
}
benchmark::Initialize(&argc, argv);
benchmark::RunSpecifiedBenchmarks();
benchmark::Shutdown();
return 0;
}
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