2 files changed, 87 insertions, 0 deletions
diff --git a/absl/numeric/BUILD.bazel b/absl/numeric/BUILD.bazel
index 1f9e0f20..eaa27dfd 100644
--- a/absl/numeric/BUILD.bazel
+++ b/absl/numeric/BUILD.bazel
@@ -37,6 +37,20 @@ cc_library(
     ],
 )
 
+cc_binary(
+    name = "bits_benchmark",
+    testonly = 1,
+    srcs = ["bits_benchmark.cc"],
+    copts = ABSL_DEFAULT_COPTS,
+    linkopts = ABSL_DEFAULT_LINKOPTS,
+    deps = [
+        ":bits",
+        "//absl/base:core_headers",
+        "//absl/random",
+        "@com_github_google_benchmark//:benchmark_main",
+    ],
+)
+
 cc_test(
     name = "bits_test",
     size = "small",
diff --git a/absl/numeric/bits_benchmark.cc b/absl/numeric/bits_benchmark.cc
new file mode 100644
index 00000000..3de1dbfa
--- /dev/null
+++ b/absl/numeric/bits_benchmark.cc
@@ -0,0 +1,73 @@
+// Copyright 2022 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cstdint>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+#include "absl/base/optimization.h"
+#include "absl/numeric/bits.h"
+#include "absl/random/random.h"
+
+namespace absl {
+namespace {
+
+template <typename T>
+static void BM_bitwidth(benchmark::State& state) {
+  const int count = state.range(0);
+
+  absl::BitGen rng;
+  std::vector<T> values;
+  values.reserve(count);
+  for (int i = 0; i < count; ++i) {
+    values.push_back(absl::Uniform<T>(rng, 0, std::numeric_limits<T>::max()));
+  }
+
+  while (state.KeepRunningBatch(count)) {
+    for (int i = 0; i < count; ++i) {
+      benchmark::DoNotOptimize(values[i]);
+    }
+  }
+}
+BENCHMARK_TEMPLATE(BM_bitwidth, uint8_t)->Range(1, 1 << 20);
+BENCHMARK_TEMPLATE(BM_bitwidth, uint16_t)->Range(1, 1 << 20);
+BENCHMARK_TEMPLATE(BM_bitwidth, uint32_t)->Range(1, 1 << 20);
+BENCHMARK_TEMPLATE(BM_bitwidth, uint64_t)->Range(1, 1 << 20);
+
+template <typename T>
+static void BM_bitwidth_nonzero(benchmark::State& state) {
+  const int count = state.range(0);
+
+  absl::BitGen rng;
+  std::vector<T> values;
+  values.reserve(count);
+  for (int i = 0; i < count; ++i) {
+    values.push_back(absl::Uniform<T>(rng, 1, std::numeric_limits<T>::max()));
+  }
+
+  while (state.KeepRunningBatch(count)) {
+    for (int i = 0; i < count; ++i) {
+      const T value = values[i];
+      ABSL_INTERNAL_ASSUME(value > 0);
+      benchmark::DoNotOptimize(value);
+    }
+  }
+}
+BENCHMARK_TEMPLATE(BM_bitwidth_nonzero, uint8_t)->Range(1, 1 << 20);
+BENCHMARK_TEMPLATE(BM_bitwidth_nonzero, uint16_t)->Range(1, 1 << 20);
+BENCHMARK_TEMPLATE(BM_bitwidth_nonzero, uint32_t)->Range(1, 1 << 20);
+BENCHMARK_TEMPLATE(BM_bitwidth_nonzero, uint64_t)->Range(1, 1 << 20);
+
+}  // namespace
+}  // namespace absl