Adding Google benchmarking library.

third_party/google_benchmark/test/multiple_ranges_test.cc

+#include "benchmark/benchmark.h"
+
+#include <cassert>
+#include <set>
+
+class MultipleRangesFixture : public ::benchmark::Fixture {
+ public:
+  MultipleRangesFixture()
+      : expectedValues({{1, 3, 5},
+                        {1, 3, 8},
+                        {1, 3, 15},
+                        {2, 3, 5},
+                        {2, 3, 8},
+                        {2, 3, 15},
+                        {1, 4, 5},
+                        {1, 4, 8},
+                        {1, 4, 15},
+                        {2, 4, 5},
+                        {2, 4, 8},
+                        {2, 4, 15},
+                        {1, 7, 5},
+                        {1, 7, 8},
+                        {1, 7, 15},
+                        {2, 7, 5},
+                        {2, 7, 8},
+                        {2, 7, 15},
+                        {7, 6, 3}}) {}
+
+  void SetUp(const ::benchmark::State& state) {
+    std::vector<int> ranges = {state.range(0), state.range(1), state.range(2)};
+
+    assert(expectedValues.find(ranges) != expectedValues.end());
+
+    actualValues.insert(ranges);
+  }
+
+  virtual ~MultipleRangesFixture() {
+    assert(actualValues.size() == expectedValues.size());
+  }
+
+  std::set<std::vector<int>> expectedValues;
+  std::set<std::vector<int>> actualValues;
+};
+
+BENCHMARK_DEFINE_F(MultipleRangesFixture, Empty)(benchmark::State& state) {
+  while (state.KeepRunning()) {
+    int product = state.range(0) * state.range(1) * state.range(2);
+    for (int x = 0; x < product; x++) {
+      benchmark::DoNotOptimize(x);
+    }
+  }
+}
+
+BENCHMARK_REGISTER_F(MultipleRangesFixture, Empty)
+    ->RangeMultiplier(2)
+    ->Ranges({{1, 2}, {3, 7}, {5, 15}})
+    ->Args({7, 6, 3});
+
+void BM_CheckDefaultArgument(benchmark::State& state) {
+  // Test that the 'range()' without an argument is the same as 'range(0)'.
+  assert(state.range() == state.range(0));
+  assert(state.range() != state.range(1));
+  while (state.KeepRunning()) {
+  }
+}
+BENCHMARK(BM_CheckDefaultArgument)->Ranges({{1, 5}, {6, 10}});
+
+static void BM_MultipleRanges(benchmark::State& st) {
+  while (st.KeepRunning()) {
+  }
+}
+BENCHMARK(BM_MultipleRanges)->Ranges({{5, 5}, {6, 6}});
+
+BENCHMARK_MAIN()