1 // Copyright 2022 The Abseil Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include <cstdint>
16 #include <vector>
17
18 #include "benchmark/benchmark.h"
19 #include "absl/base/optimization.h"
20 #include "absl/numeric/bits.h"
21 #include "absl/random/random.h"
22
23 namespace absl {
24 namespace {
25
26 template <typename T>
BM_bit_width(benchmark::State & state)27 static void BM_bit_width(benchmark::State& state) {
28 const auto count = static_cast<size_t>(state.range(0));
29
30 absl::BitGen rng;
31 std::vector<T> values;
32 values.reserve(count);
33 for (size_t i = 0; i < count; ++i) {
34 values.push_back(absl::Uniform<T>(rng, 0, std::numeric_limits<T>::max()));
35 }
36
37 while (state.KeepRunningBatch(static_cast<int64_t>(count))) {
38 for (size_t i = 0; i < count; ++i) {
39 benchmark::DoNotOptimize(absl::bit_width(values[i]));
40 }
41 }
42 }
43 BENCHMARK_TEMPLATE(BM_bit_width, uint8_t)->Range(1, 1 << 20);
44 BENCHMARK_TEMPLATE(BM_bit_width, uint16_t)->Range(1, 1 << 20);
45 BENCHMARK_TEMPLATE(BM_bit_width, uint32_t)->Range(1, 1 << 20);
46 BENCHMARK_TEMPLATE(BM_bit_width, uint64_t)->Range(1, 1 << 20);
47
48 template <typename T>
BM_bit_width_nonzero(benchmark::State & state)49 static void BM_bit_width_nonzero(benchmark::State& state) {
50 const auto count = static_cast<size_t>(state.range(0));
51
52 absl::BitGen rng;
53 std::vector<T> values;
54 values.reserve(count);
55 for (size_t i = 0; i < count; ++i) {
56 values.push_back(absl::Uniform<T>(rng, 1, std::numeric_limits<T>::max()));
57 }
58
59 while (state.KeepRunningBatch(static_cast<int64_t>(count))) {
60 for (size_t i = 0; i < count; ++i) {
61 const T value = values[i];
62 ABSL_ASSUME(value > 0);
63 benchmark::DoNotOptimize(absl::bit_width(value));
64 }
65 }
66 }
67 BENCHMARK_TEMPLATE(BM_bit_width_nonzero, uint8_t)->Range(1, 1 << 20);
68 BENCHMARK_TEMPLATE(BM_bit_width_nonzero, uint16_t)->Range(1, 1 << 20);
69 BENCHMARK_TEMPLATE(BM_bit_width_nonzero, uint32_t)->Range(1, 1 << 20);
70 BENCHMARK_TEMPLATE(BM_bit_width_nonzero, uint64_t)->Range(1, 1 << 20);
71
72 } // namespace
73 } // namespace absl
74