libcxx/test/benchmarks/algorithms/modifying/transform.unary.bench.cpp

//===----------------------------------------------------------------------===//
//
// 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 <iterator>
#include <list>
#include <string>
#include <vector>

#include "benchmark/benchmark.h"
#include "../../GenerateInput.h"

int main(int argc, char** argv) {
  auto std_transform = [](auto first, auto last, auto out, auto f) { return std::transform(first, last, out, f); };

  // {std,ranges}::transform(normal container)
  {
    auto bm = []<class Container>(std::string name, auto transform) {
      benchmark::RegisterBenchmark(
          name,
          [transform](auto& st) {
            std::size_t const size = st.range(0);
            using ValueType        = typename Container::value_type;
            Container c;
            std::generate_n(std::back_inserter(c), size, [] { return Generate<ValueType>::random(); });

            std::vector<ValueType> out(size);

            auto f = [](auto element) {
              benchmark::DoNotOptimize(element);
              return element;
            };

            for ([[maybe_unused]] auto _ : st) {
              benchmark::DoNotOptimize(c);
              benchmark::DoNotOptimize(out);
              auto result = transform(c.begin(), c.end(), out.begin(), f);
              benchmark::DoNotOptimize(result);
            }
          })
          ->Arg(32)
          ->Arg(50) // non power-of-two
          ->Arg(1024)
          ->Arg(8192);
    };
    bm.operator()<std::vector<int>>("std::transform(vector<int>) (identity transform)", std_transform);
    bm.operator()<std::deque<int>>("std::transform(deque<int>) (identity transform)", std_transform);
    bm.operator()<std::list<int>>("std::transform(list<int>) (identity transform)", std_transform);
    bm.operator()<std::vector<int>>("rng::transform(vector<int>) (identity transform)", std::ranges::transform);
    bm.operator()<std::deque<int>>("rng::transform(deque<int>) (identity transform)", std::ranges::transform);
    bm.operator()<std::list<int>>("rng::transform(list<int>) (identity transform)", std::ranges::transform);
  }

  benchmark::Initialize(&argc, argv);
  benchmark::RunSpecifiedBenchmarks();
  benchmark::Shutdown();
  return 0;
}