[libc++] Add a benchmark for std::num_get

libcxx/test/benchmarks/locale/num_get.bench.cpp

@@ -0,0 +1,44 @@
+
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <ios>
+#include <locale>
+
+#include <benchmark/benchmark.h>
+
+struct num_get : std::num_get<char, std::string::iterator> {};
+
+template <class T>
+void BM_num_get(benchmark::State& state) {
+  auto val = std::string("123");
+  std::ios ios(nullptr);
+  num_get np;
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(val);
+    T out;
+    std::ios_base::iostate err = ios.goodbit;
+    benchmark::DoNotOptimize(np.get(val.begin(), val.end(), ios, err, out));
+    benchmark::DoNotOptimize(out);
+  }
+}
+
+BENCHMARK(BM_num_get<bool>);
+BENCHMARK(BM_num_get<long>);
+BENCHMARK(BM_num_get<long long>);
+BENCHMARK(BM_num_get<unsigned short>);
+BENCHMARK(BM_num_get<unsigned int>);
+BENCHMARK(BM_num_get<unsigned long>);
+BENCHMARK(BM_num_get<unsigned long long>);
+BENCHMARK(BM_num_get<float>);
+BENCHMARK(BM_num_get<double>);
+BENCHMARK(BM_num_get<long double>);
+BENCHMARK(BM_num_get<void*>);
+
+BENCHMARK_MAIN();