1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef BENCHMARK_VARIANT_BENCHMARKS_H
11#define BENCHMARK_VARIANT_BENCHMARKS_H
12
13#include <array>
14#include <cstddef>
15#include <tuple>
16#include <type_traits>
17#include <variant>
18
19#include "benchmark/benchmark.h"
20
21#include "GenerateInput.h"
22
23namespace VariantBenchmarks {
24
25template <std::size_t I>
26struct S {
27  static constexpr size_t v = I;
28};
29
30template <std::size_t N, std::size_t... Is>
31static auto genVariants(std::index_sequence<Is...>) {
32  using V = std::variant<S<Is>...>;
33  using F = V (*)();
34  static constexpr F fs[] = {[] { return V(std::in_place_index<Is>); }...};
35
36  std::array<V, N> result = {};
37  for (auto& v : result) {
38    v = fs[getRandomInteger(0ul, sizeof...(Is) - 1)]();
39  }
40
41  return result;
42}
43
44template <std::size_t N, std::size_t Alts>
45static void BM_Visit(benchmark::State& state) {
46  auto args = genVariants<N>(std::make_index_sequence<Alts>{});
47  for (auto _ : state) {
48    benchmark::DoNotOptimize(std::apply(
49        [](auto... vs) {
50          return std::visit([](auto... is) { return (is.v + ... + 0); }, vs...);
51        },
52        args));
53  }
54}
55
56} // end namespace VariantBenchmarks
57
58#endif // BENCHMARK_VARIANT_BENCHMARKS_H
59