66fa2f9a14
The variant benchmarks are incredibly slow to compile and run currently. This is due to them being incredibly exhaustive. This is usually a good thing, but the exhaustiveness makes it prohibitive to actually run the benchmarks. Even the new, incredibly reduced, set still requires almost 40 seconds to just compile on my system.
56 lines
2.0 KiB
C++
56 lines
2.0 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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#include <array>
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#include <variant>
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#include "benchmark/benchmark.h"
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#include "GenerateInput.h"
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template <std::size_t I>
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struct S {
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static constexpr size_t v = I;
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};
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template <std::size_t N, std::size_t... Is>
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static auto genVariants(std::index_sequence<Is...>) {
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using V = std::variant<S<Is>...>;
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using F = V (*)();
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static constexpr F fs[] = {[] { return V(std::in_place_index<Is>); }...};
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std::array<V, N> result = {};
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for (auto& v : result) {
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v = fs[getRandomInteger(std::size_t(0), sizeof...(Is) - 1)]();
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}
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return result;
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}
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template <std::size_t N, std::size_t Alts>
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static void BM_Visit(benchmark::State& state) {
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auto args = genVariants<N>(std::make_index_sequence<Alts>{});
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for (auto _ : state) {
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benchmark::DoNotOptimize(
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std::apply([](auto... vs) { return std::visit([](auto... is) { return (is.v + ... + 0); }, vs...); }, args));
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}
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}
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BENCHMARK(BM_Visit<1, 1>)->Name("std::variant<1-alt>::visit() (1 variant)");
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BENCHMARK(BM_Visit<1, 8>)->Name("std::variant<8-alts>::visit() (1 variant)");
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BENCHMARK(BM_Visit<1, 100>)->Name("std::variant<100-alts>::visit() (1 variant)");
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BENCHMARK(BM_Visit<2, 1>)->Name("std::variant<1-alt>::visit() (2 variants)");
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BENCHMARK(BM_Visit<2, 8>)->Name("std::variant<8-alts>::visit() (2 variants)");
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BENCHMARK(BM_Visit<2, 50>)->Name("std::variant<50-alts>::visit() (2 variants)");
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BENCHMARK(BM_Visit<3, 1>)->Name("std::variant<1-alt>::visit() (3 variants)");
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BENCHMARK(BM_Visit<3, 8>)->Name("std::variant<8-alts>::visit() (3 variants)");
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BENCHMARK(BM_Visit<3, 20>)->Name("std::variant<20-alts>::visit() (3 variants)");
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BENCHMARK_MAIN();
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