[perf] Add set ieration and lookup benchmarks.

perf/benchmark-set.cc

@@ -18,6 +18,7 @@ void RandomSet(unsigned size, unsigned max_value, hb_set_t* out) {
   }
 }
 
+/* Insert a single value into set of varying sizes. */
 static void BM_SetInsert(benchmark::State& state) {
   unsigned set_size = state.range(0);
   unsigned max_value = state.range(0) * state.range(1);
@@ -46,4 +47,51 @@ BENCHMARK(BM_SetInsert)
         benchmark::CreateDenseRange(2, 8, /*step=*/2) // Density
       });
 
+/* Single value lookup on sets of various sizes. */
+static void BM_SetLookup(benchmark::State& state) {
+  unsigned set_size = state.range(0);
+  unsigned max_value = state.range(0) * state.range(1);
+
+  hb_set_t* original = hb_set_create ();
+  RandomSet(set_size, max_value, original);
+  assert(hb_set_get_population(original) == set_size);
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(
+        hb_set_has (original, rand() % max_value));
+  }
+
+  hb_set_destroy(original);
+}
+BENCHMARK(BM_SetLookup)
+    ->ArgsProduct({
+        benchmark::CreateRange(1 << 10, 1 << 16, 8), // Set size
+        benchmark::CreateDenseRange(2, 8, /*step=*/2) // Density
+      });
+
+/* Full iteration of sets of varying sizes. */
+static void BM_SetIteration(benchmark::State& state) {
+  unsigned set_size = state.range(0);
+  unsigned max_value = state.range(0) * state.range(1);
+
+  hb_set_t* original = hb_set_create ();
+  RandomSet(set_size, max_value, original);
+  assert(hb_set_get_population(original) == set_size);
+
+  for (auto _ : state) {
+    hb_codepoint_t cp = HB_SET_VALUE_INVALID;
+    while (hb_set_next (original, &cp)) {
+      continue;
+    }
+  }
+
+  hb_set_destroy(original);
+}
+BENCHMARK(BM_SetIteration)
+    ->Unit(benchmark::kMicrosecond)
+    ->ArgsProduct({
+        benchmark::CreateRange(1 << 10, 1 << 16, 8), // Set size
+        benchmark::CreateDenseRange(2, 8, /*step=*/2) // Density
+      });
+
 BENCHMARK_MAIN();