27a062e9ca
The binary version is four times faster than current implementation in my setup, and generally considered a better implementation. Code inspired by https://en.algorithmica.org/hpc/algorithms/gcd/ which itself is inspired by https://lemire.me/blog/2013/12/26/fastest-way-to-compute-the-greatest-common-divisor/ Fix #77648
54 lines
1.7 KiB
C++
54 lines
1.7 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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#include <array>
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#include <benchmark/benchmark.h>
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#include <cstring>
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#include <numeric>
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#include <random>
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template <class T>
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static std::array<T, 1000> generate(std::uniform_int_distribution<T> distribution = std::uniform_int_distribution<T>{
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std::numeric_limits<T>::min() + 1, std::numeric_limits<T>::max()}) {
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std::mt19937 generator;
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std::array<T, 1000> result;
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std::generate_n(result.begin(), result.size(), [&] { return distribution(generator); });
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return result;
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}
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static void bm_gcd_random(benchmark::State& state) {
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std::array data = generate<int>();
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while (state.KeepRunningBatch(data.size()))
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for (auto v0 : data)
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for (auto v1 : data)
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benchmark::DoNotOptimize(std::gcd(v0, v1));
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}
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BENCHMARK(bm_gcd_random);
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static void bm_gcd_trivial(benchmark::State& state) {
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int lhs = ~static_cast<int>(0), rhs = 1;
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for (auto _ : state) {
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benchmark::DoNotOptimize(lhs);
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benchmark::DoNotOptimize(rhs);
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benchmark::DoNotOptimize(std::gcd(lhs, rhs));
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}
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}
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BENCHMARK(bm_gcd_trivial);
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static void bm_gcd_complex(benchmark::State& state) {
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int lhs = 2971215073, rhs = 1836311903;
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for (auto _ : state) {
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benchmark::DoNotOptimize(lhs);
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benchmark::DoNotOptimize(rhs);
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benchmark::DoNotOptimize(std::gcd(lhs, rhs));
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}
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}
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BENCHMARK(bm_gcd_complex);
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BENCHMARK_MAIN();
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