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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 <iterator>
#include <list>
#include <string>
#include <utility>
#include <vector>
#include "benchmark/benchmark.h"
#include "../../GenerateInput.h"
int main(int argc, char** argv) {
auto std_shift_left = [](auto first, auto last, auto n) { return std::shift_left(first, last, n); };
// Benchmark std::shift_left where we shift exactly one element, which is the worst case.
{
auto bm = []<class Container>(std::string name, auto shift_left) {
benchmark::RegisterBenchmark(
name,
[shift_left](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::size_t n = 1;
// To avoid ending up with a fully moved-from range, restore the element that gets
// overwritten by the shift after performing the shift.
auto first_element = c.begin();
auto last_element = std::next(c.begin(), size - 1);
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(c);
benchmark::DoNotOptimize(n);
ValueType tmp = *first_element;
auto result = shift_left(c.begin(), c.end(), n);
*last_element = std::move(tmp);
benchmark::DoNotOptimize(result);
}
})
->Arg(32)
->Arg(50) // non power-of-two
->Arg(1024)
->Arg(8192);
};
bm.operator()<std::vector<int>>("std::shift_left(vector<int>)", std_shift_left);
bm.operator()<std::deque<int>>("std::shift_left(deque<int>)", std_shift_left);
bm.operator()<std::list<int>>("std::shift_left(list<int>)", std_shift_left);
// ranges::shift_left not implemented yet
}
benchmark::Initialize(&argc, argv);
benchmark::RunSpecifiedBenchmarks();
benchmark::Shutdown();
return 0;
}
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