[libcxx] Speeding up partition_point/lower_bound/upper_bound
This is a re-application of r345525, which had been reverted by fear of
a regression.
Reviewed as https://reviews.llvm.org/D53994.
Thanks to Denis Yaroshevskiy for the patch.
llvm-svn: 349358
diff --git a/libcxx/benchmarks/algorithms.partition_point.bench.cpp b/libcxx/benchmarks/algorithms.partition_point.bench.cpp
new file mode 100644
index 0000000..00a3bb2
--- /dev/null
+++ b/libcxx/benchmarks/algorithms.partition_point.bench.cpp
@@ -0,0 +1,124 @@
+#include <array>
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <tuple>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+
+#include "CartesianBenchmarks.hpp"
+#include "GenerateInput.hpp"
+
+namespace {
+
+template <typename I, typename N>
+std::array<I, 10> every_10th_percentile_N(I first, N n) {
+ N step = n / 10;
+ std::array<I, 10> res;
+
+ for (size_t i = 0; i < 10; ++i) {
+ res[i] = first;
+ std::advance(first, step);
+ }
+
+ return res;
+}
+
+template <class IntT>
+struct TestIntBase {
+ static std::vector<IntT> generateInput(size_t size) {
+ std::vector<IntT> Res(size);
+ std::generate(Res.begin(), Res.end(),
+ [] { return getRandomInteger<IntT>(); });
+ return Res;
+ }
+};
+
+struct TestInt32 : TestIntBase<std::int32_t> {
+ static constexpr const char* Name = "TestInt32";
+};
+
+struct TestInt64 : TestIntBase<std::int64_t> {
+ static constexpr const char* Name = "TestInt64";
+};
+
+struct TestUint32 : TestIntBase<std::uint32_t> {
+ static constexpr const char* Name = "TestUint32";
+};
+
+struct TestMediumString {
+ static constexpr const char* Name = "TestMediumString";
+ static constexpr size_t StringSize = 32;
+
+ static std::vector<std::string> generateInput(size_t size) {
+ std::vector<std::string> Res(size);
+ std::generate(Res.begin(), Res.end(), [] { return getRandomString(StringSize); });
+ return Res;
+ }
+};
+
+using AllTestTypes = std::tuple<TestInt32, TestInt64, TestUint32, TestMediumString>;
+
+struct LowerBoundAlg {
+ template <class I, class V>
+ I operator()(I first, I last, const V& value) const {
+ return std::lower_bound(first, last, value);
+ }
+
+ static constexpr const char* Name = "LowerBoundAlg";
+};
+
+struct UpperBoundAlg {
+ template <class I, class V>
+ I operator()(I first, I last, const V& value) const {
+ return std::upper_bound(first, last, value);
+ }
+
+ static constexpr const char* Name = "UpperBoundAlg";
+};
+
+struct EqualRangeAlg {
+ template <class I, class V>
+ std::pair<I, I> operator()(I first, I last, const V& value) const {
+ return std::equal_range(first, last, value);
+ }
+
+ static constexpr const char* Name = "EqualRangeAlg";
+};
+
+using AllAlgs = std::tuple<LowerBoundAlg, UpperBoundAlg, EqualRangeAlg>;
+
+template <class Alg, class TestType>
+struct PartitionPointBench {
+ size_t Quantity;
+
+ std::string name() const {
+ return std::string("PartitionPointBench_") + Alg::Name + "_" +
+ TestType::Name + '/' + std::to_string(Quantity);
+ }
+
+ void run(benchmark::State& state) const {
+ auto Data = TestType::generateInput(Quantity);
+ std::sort(Data.begin(), Data.end());
+ auto Every10Percentile = every_10th_percentile_N(Data.begin(), Data.size());
+
+ for (auto _ : state) {
+ for (auto Test : Every10Percentile)
+ benchmark::DoNotOptimize(Alg{}(Data.begin(), Data.end(), *Test));
+ }
+ }
+};
+
+} // namespace
+
+int main(int argc, char** argv) {
+ benchmark::Initialize(&argc, argv);
+ if (benchmark::ReportUnrecognizedArguments(argc, argv))
+ return 1;
+
+ const std::vector<size_t> Quantities = {1 << 8, 1 << 10, 1 << 20};
+ makeCartesianProductBenchmark<PartitionPointBench, AllAlgs, AllTestTypes>(
+ Quantities);
+ benchmark::RunSpecifiedBenchmarks();
+}