Add benchmark tests

Author: winner245

libcxx/include/__vector/vector.h

@@ -1269,8 +1269,8 @@ vector<_Tp, _Allocator>::__insert_with_sentinel(const_iterator __position, _Inpu
     std::__uninitialized_allocator_relocate(
         __alloc_, std::__to_address(__v.__begin_), std::__to_address(__v.__end_), std::__to_address(__merged.__end_));
     __merged.__end_ += __v.size();
-    __v.__end_   = __v.__begin_;
-    __p          = __swap_out_circular_buffer(__merged, __p);
+    __v.__end_ = __v.__begin_;
+    __p        = __swap_out_circular_buffer(__merged, __p);
   }
   return __make_iter(__p);
 }

libcxx/test/benchmarks/GenerateInput.h

@@ -134,7 +134,14 @@ std::vector<std::vector<IntT>> getRandomIntegerInputsWithLength(std::size_t N, s
   return inputs;
 }
 
-inline std::vector<std::string> getPrefixedRandomStringInputs(std::size_t N) {
+inline std::vector<std::string> getSSORandomStringInputs(size_t N) {
+  std::vector<std::string> inputs;
+  for (size_t i = 0; i < N; ++i)
+    inputs.push_back(getRandomString(10)); // SSO
+  return inputs;
+}
+
+inline std::vector<std::string> getPrefixedRandomStringInputs(size_t N) {
   std::vector<std::string> inputs;
   inputs.reserve(N);
   constexpr int kSuffixLength = 32;

libcxx/test/benchmarks/containers/ContainerBenchmarks.h

@@ -135,6 +135,66 @@ void BM_InsertValueRehash(benchmark::State& st, Container c, GenInputs gen) {
   }
 }
 
+template <class Container, class GenInputs>
+void BM_Insert_InputIterIter_NoRealloc(benchmark::State& st, Container c, GenInputs gen) {
+  auto in = gen(st.range(0));
+  DoNotOptimizeData(in);
+  const auto size = c.size();
+  const auto beg  = cpp17_input_iterator(in.begin());
+  const auto end  = cpp17_input_iterator(in.end());
+  c.reserve(size + in.size()); // force no reallocation
+  for (auto _ : st) {
+    benchmark::DoNotOptimize(&(*c.insert(c.begin(), beg, end)));
+    st.PauseTiming();
+    c.erase(c.begin() + size, c.end()); // avoid the container to grow indefinitely
+    st.ResumeTiming();
+    DoNotOptimizeData(c);
+    benchmark::ClobberMemory();
+  }
+}
+
+template <class Container, class GenInputs>
+void BM_Insert_InputIterIter_Realloc_HalfFilled(benchmark::State& st, Container, GenInputs gen) {
+  const auto size = st.range(0);
+  Container a     = gen(size);
+  Container in    = gen(size + 10);
+  DoNotOptimizeData(a);
+  DoNotOptimizeData(in);
+  const auto beg = cpp17_input_iterator(in.begin());
+  const auto end = cpp17_input_iterator(in.end());
+  for (auto _ : st) {
+    st.PauseTiming();
+    Container c;
+    c.reserve(size * 2); // Reallocation with half-filled container
+    c = a;
+    st.ResumeTiming();
+    benchmark::DoNotOptimize(&(*c.insert(c.begin(), beg, end)));
+    DoNotOptimizeData(c);
+    benchmark::ClobberMemory();
+  }
+}
+
+template <class Container, class GenInputs>
+void BM_Insert_InputIterIter_Realloc_NearFull(benchmark::State& st, Container, GenInputs gen) {
+  const auto size = st.range(0);
+  Container a     = gen(size);
+  Container in    = gen(10);
+  DoNotOptimizeData(a);
+  DoNotOptimizeData(in);
+  const auto beg = cpp17_input_iterator(in.begin());
+  const auto end = cpp17_input_iterator(in.end());
+  for (auto _ : st) {
+    st.PauseTiming();
+    Container c;
+    c.reserve(size + 5); // Reallocation almost-full container
+    c = a;
+    st.ResumeTiming();
+    benchmark::DoNotOptimize(&(*c.insert(c.begin(), beg, end)));
+    DoNotOptimizeData(c);
+    benchmark::ClobberMemory();
+  }
+}
+
 template <class Container, class GenInputs>
 void BM_InsertDuplicate(benchmark::State& st, Container c, GenInputs gen) {
   auto in        = gen(st.range(0));

libcxx/test/benchmarks/containers/vector_operations.bench.cpp

@@ -91,4 +91,18 @@ BENCHMARK_CAPTURE(BM_AssignInputIterIter<100>,
                   getRandomIntegerInputsWithLength<int>)
     ->Args({TestNumInputs, TestNumInputs});
 
+BENCHMARK_CAPTURE(BM_Insert_InputIterIter_NoRealloc, vector_int, std::vector<int>(100, 1), getRandomIntegerInputs<int>)
+    ->Arg(514048);
+BENCHMARK_CAPTURE(
+    BM_Insert_InputIterIter_Realloc_HalfFilled, vector_int, std::vector<int>{}, getRandomIntegerInputs<int>)
+    ->Arg(514048);
+BENCHMARK_CAPTURE(BM_Insert_InputIterIter_Realloc_NearFull, vector_int, std::vector<int>{}, getRandomIntegerInputs<int>)
+    ->Arg(514048);
+BENCHMARK_CAPTURE(
+    BM_Insert_InputIterIter_Realloc_HalfFilled, vector_string, std::vector<std::string>{}, getSSORandomStringInputs)
+    ->Arg(514048);
+BENCHMARK_CAPTURE(
+    BM_Insert_InputIterIter_Realloc_NearFull, vector_string, std::vector<std::string>{}, getSSORandomStringInputs)
+    ->Arg(514048);
+
 BENCHMARK_MAIN();