swap_ranges benchmark (#4589)

Co-authored-by: Stephan T. Lavavej <stl@nuwen.net>

benchmarks/CMakeLists.txt

@@ -119,6 +119,7 @@ add_benchmark(priority_queue_push_range src/priority_queue_push_range.cpp)
 add_benchmark(random_integer_generation src/random_integer_generation.cpp)
 add_benchmark(replace src/replace.cpp)
 add_benchmark(std_copy src/std_copy.cpp)
+add_benchmark(swap_ranges src/swap_ranges.cpp)
 
 add_benchmark(vector_bool_copy src/std/containers/sequences/vector.bool/copy/test.cpp)
 add_benchmark(vector_bool_copy_n src/std/containers/sequences/vector.bool/copy_n/test.cpp)

benchmarks/src/swap_ranges.cpp

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include <algorithm>
+#include <benchmark/benchmark.h>
+#include <cstddef>
+#include <cstdint>
+#include <vector>
+
+using namespace std;
+
+template <class T>
+void bm(benchmark::State& state) {
+    vector<T> a(static_cast<size_t>(state.range(0)), T{'a'});
+    vector<T> b(static_cast<size_t>(state.range(0)), T{'b'});
+
+    for (auto _ : state) {
+        swap_ranges(a.begin(), a.end(), b.begin());
+        benchmark::DoNotOptimize(a);
+        benchmark::DoNotOptimize(b);
+    }
+}
+
+BENCHMARK(bm<uint8_t>)->Arg(1)->Arg(5)->Arg(15)->Arg(26)->Arg(38)->Arg(60)->Arg(125)->Arg(800)->Arg(3000)->Arg(9000);
+
+BENCHMARK_MAIN();