[libcxx-commits] [libcxx] [libc++] Add benchmarks for copy algorithms (PR #127328)

[Nikolas Klauser via libcxx-commits]

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@@ -0,0 +1,87 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <algorithm>
+#include <deque>
+#include <iterator>
+#include <list>
+#include <string>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+#include "../../GenerateInput.h"
+#include "test_macros.h"
+
+template <class Container, class Operation>
+void bm_general(std::string operation_name, Operation copy) {
+  auto bench = [copy](auto& st) {
+    auto const size = st.range(0);
+    using ValueType = typename Container::value_type;
+    Container c;
+    std::generate_n(std::back_inserter(c), size, [] { return Generate<ValueType>::random(); });
+
+    std::vector<ValueType> out(size);
+
+    for ([[maybe_unused]] auto _ : st) {
+      auto result = copy(c.begin(), c.end(), out.begin());
+      benchmark::DoNotOptimize(result);
+      benchmark::DoNotOptimize(out);
+      benchmark::DoNotOptimize(c);
+      benchmark::ClobberMemory();
+    }
+  };
+  benchmark::RegisterBenchmark(operation_name, bench)->Range(8, 1 << 20);
+}
+
+template <bool Aligned, class Operation>
+static void bm_vector_bool(std::string operation_name, Operation copy) {
+  auto bench = [copy](auto& st) {
+    auto n = st.range();
+    std::vector<bool> in(n, true);
+    std::vector<bool> out(Aligned ? n : n + 8);
+    benchmark::DoNotOptimize(&in);
+    auto first = in.begin();
+    auto last  = in.end();
+    auto dst   = Aligned ? out.begin() : out.begin() + 4;
+    for ([[maybe_unused]] auto _ : st) {
+      auto result = copy(first, last, dst);
+      benchmark::DoNotOptimize(result);
+      benchmark::DoNotOptimize(out);
+      benchmark::ClobberMemory();
+    }
+  };
+  benchmark::RegisterBenchmark(operation_name, bench)->Range(64, 1 << 20);
+}
+
+int main(int argc, char** argv) {
+  auto std_copy    = [](auto first, auto last, auto out) { return std::copy(first, last, out); };
+  auto ranges_copy = [](auto first, auto last, auto out) { return std::ranges::copy(first, last, out); };
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philnik777 wrote:

I don't think we need a wrapper for the `ranges` version, since they are CPOs.

https://github.com/llvm/llvm-project/pull/127328