1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // UNSUPPORTED: c++03 10 11 #include <cstdint> 12 #include <cstddef> 13 #include <functional> 14 15 #include "benchmark/benchmark.h" 16 17 #include "GenerateInput.h" 18 #include "test_macros.h" 19 20 constexpr std::size_t TestNumInputs = 1024; 21 22 template <class HashFn, class GenInputs> 23 void BM_Hash(benchmark::State& st, HashFn fn, GenInputs gen) { 24 auto in = gen(st.range(0)); 25 const auto end = in.data() + in.size(); 26 std::size_t last_hash = 0; 27 benchmark::DoNotOptimize(&last_hash); 28 while (st.KeepRunning()) { 29 for (auto it = in.data(); it != end; ++it) { 30 benchmark::DoNotOptimize(last_hash += fn(*it)); 31 } 32 benchmark::ClobberMemory(); 33 } 34 } 35 36 BENCHMARK_CAPTURE(BM_Hash, uint32_random_std_hash, std::hash<uint32_t>{}, getRandomIntegerInputs<uint32_t>) 37 ->Arg(TestNumInputs); 38 39 BENCHMARK_CAPTURE(BM_Hash, uint32_top_std_hash, std::hash<uint32_t>{}, getSortedTopBitsIntegerInputs<uint32_t>) 40 ->Arg(TestNumInputs); 41 42 BENCHMARK_MAIN(); 43