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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 <cassert>
#include <cstddef>
#include <deque>
#include <forward_list>
#include <list>
#include <string>
#include <vector>
#include <benchmark/benchmark.h>
#include "../../GenerateInput.h"
int main(int argc, char** argv) {
auto std_find_end = [](auto first1, auto last1, auto first2, auto last2) {
return std::find_end(first1, last1, first2, last2);
};
auto std_find_end_pred = [](auto first1, auto last1, auto first2, auto last2) {
return std::find_end(first1, last1, first2, last2, [](auto x, auto y) {
benchmark::DoNotOptimize(x);
benchmark::DoNotOptimize(y);
return x == y;
});
};
auto ranges_find_end_pred = [](auto first1, auto last1, auto first2, auto last2) {
return std::ranges::find_end(first1, last1, first2, last2, [](auto x, auto y) {
benchmark::DoNotOptimize(x);
benchmark::DoNotOptimize(y);
return x == y;
});
};
auto register_benchmarks = [&](auto bm, std::string comment) {
// {std,ranges}::find_end(it1, it1, it2, it2)
bm.template operator()<std::vector<int>>("std::find_end(vector<int>) (" + comment + ")", std_find_end);
bm.template operator()<std::deque<int>>("std::find_end(deque<int>) (" + comment + ")", std_find_end);
bm.template operator()<std::list<int>>("std::find_end(list<int>) (" + comment + ")", std_find_end);
bm.template operator()<std::forward_list<int>>("std::find_end(forward_list<int>) (" + comment + ")", std_find_end);
bm.template operator()<std::vector<int>>("rng::find_end(vector<int>) (" + comment + ")", std::ranges::find_end);
bm.template operator()<std::deque<int>>("rng::find_end(deque<int>) (" + comment + ")", std::ranges::find_end);
bm.template operator()<std::list<int>>("rng::find_end(list<int>) (" + comment + ")", std::ranges::find_end);
bm.template operator()<std::forward_list<int>>(
"rng::find_end(forward_list<int>) (" + comment + ")", std::ranges::find_end);
// {std,ranges}::find_end(it1, it1, it2, it2, pred)
bm.template operator()<std::vector<int>>("std::find_end(vector<int>, pred) (" + comment + ")", std_find_end_pred);
bm.template operator()<std::deque<int>>("std::find_end(deque<int>, pred) (" + comment + ")", std_find_end_pred);
bm.template operator()<std::list<int>>("std::find_end(list<int>, pred) (" + comment + ")", std_find_end_pred);
bm.template operator()<std::forward_list<int>>(
"std::find_end(forward_list<int>, pred) (" + comment + ")", std_find_end_pred);
bm.template operator()<std::vector<int>>(
"rng::find_end(vector<int>, pred) (" + comment + ")", ranges_find_end_pred);
bm.template operator()<std::deque<int>>("rng::find_end(deque<int>, pred) (" + comment + ")", ranges_find_end_pred);
bm.template operator()<std::list<int>>("rng::find_end(list<int>, pred) (" + comment + ")", ranges_find_end_pred);
bm.template operator()<std::forward_list<int>>(
"rng::find_end(forward_list<int>, pred) (" + comment + ")", ranges_find_end_pred);
};
// Benchmark {std,ranges}::find_end where we never find the needle, which is the
// worst case.
{
auto bm = []<class Container>(std::string name, auto find_end) {
benchmark::RegisterBenchmark(
name,
[find_end](auto& st) {
std::size_t const size = st.range(0);
using ValueType = typename Container::value_type;
ValueType x = Generate<ValueType>::random();
ValueType y = random_different_from({x});
Container haystack(size, x);
std::size_t n = size / 10; // needle size is 10% of the haystack, but we'll never find it
assert(n > 0);
Container needle(n, y);
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(haystack);
benchmark::DoNotOptimize(needle);
auto result = find_end(haystack.begin(), haystack.end(), needle.begin(), needle.end());
benchmark::DoNotOptimize(result);
}
})
->Arg(1000) // non power-of-two
->Arg(1024)
->Arg(8192)
->Arg(1 << 20);
};
register_benchmarks(bm, "process all");
}
// Benchmark {std,ranges}::find_end where we intersperse "near matches" inside the haystack.
{
auto bm = []<class Container>(std::string name, auto find_end) {
benchmark::RegisterBenchmark(
name,
[find_end](auto& st) {
std::size_t const size = st.range(0);
using ValueType = typename Container::value_type;
ValueType x = Generate<ValueType>::random();
ValueType y = random_different_from({x});
Container haystack(size, x);
std::size_t n = size / 10; // needle size is 10% of the haystack
assert(n > 0);
Container needle(n, y);
// intersperse near-matches inside the haystack
{
auto first = haystack.begin();
for (int i = 0; i != 10; ++i) {
first = std::copy_n(needle.begin(), n - 1, first);
++first; // this causes the subsequence not to match because it has length n-1
}
}
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(haystack);
benchmark::DoNotOptimize(needle);
auto result = find_end(haystack.begin(), haystack.end(), needle.begin(), needle.end());
benchmark::DoNotOptimize(result);
}
})
->Arg(1000) // non power-of-two
->Arg(1024)
->Arg(8192);
};
register_benchmarks(bm, "near matches");
}
// Special case: the two ranges are the same length (and they are equal, which is the worst case).
{
auto bm = []<class Container>(std::string name, auto find_end) {
benchmark::RegisterBenchmark(
name,
[find_end](auto& st) {
std::size_t const size = st.range(0);
using ValueType = typename Container::value_type;
ValueType x = Generate<ValueType>::random();
Container haystack(size, x);
Container needle(size, x);
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(haystack);
benchmark::DoNotOptimize(needle);
auto result = find_end(haystack.begin(), haystack.end(), needle.begin(), needle.end());
benchmark::DoNotOptimize(result);
}
})
->Arg(1000) // non power-of-two
->Arg(1024)
->Arg(8192);
};
register_benchmarks(bm, "same length");
}
// Special case: the needle contains a single element (which we never find, i.e. the worst case).
{
auto bm = []<class Container>(std::string name, auto find_end) {
benchmark::RegisterBenchmark(
name,
[find_end](auto& st) {
std::size_t const size = st.range(0);
using ValueType = typename Container::value_type;
ValueType x = Generate<ValueType>::random();
ValueType y = random_different_from({x});
Container haystack(size, x);
Container needle(1, y);
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(haystack);
benchmark::DoNotOptimize(needle);
auto result = find_end(haystack.begin(), haystack.end(), needle.begin(), needle.end());
benchmark::DoNotOptimize(result);
}
})
->Arg(1000) // non power-of-two
->Arg(1024)
->Arg(8192);
};
register_benchmarks(bm, "single element");
}
// Special case: we have a match close to the end of the haystack (ideal case if we start searching from the end).
{
auto bm = []<class Container>(std::string name, auto find_end) {
benchmark::RegisterBenchmark(
name,
[find_end](auto& st) {
std::size_t const size = st.range(0);
using ValueType = typename Container::value_type;
ValueType x = Generate<ValueType>::random();
ValueType y = random_different_from({x});
Container haystack(size, x);
std::size_t n = size / 10; // needle size is 10% of the haystack
assert(n > 0);
Container needle(n, y);
// put the needle at 90% of the haystack
std::ranges::copy(needle, std::next(haystack.begin(), (9 * size) / 10));
for ([[maybe_unused]] auto _ : st) {
benchmark::DoNotOptimize(haystack);
benchmark::DoNotOptimize(needle);
auto result = find_end(haystack.begin(), haystack.end(), needle.begin(), needle.end());
benchmark::DoNotOptimize(result);
}
})
->Arg(1000) // non power-of-two
->Arg(1024)
->Arg(8192);
};
register_benchmarks(bm, "match near end");
}
benchmark::Initialize(&argc, argv);
benchmark::RunSpecifiedBenchmarks();
benchmark::Shutdown();
return 0;
}
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