[libcxx-commits] [libcxx] [libc++] Optimize ranges::copy{, _n} for vector<bool>::iterator (PR #121013)

[Peng Liu via libcxx-commits]

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@@ -0,0 +1,89 @@
+//===----------------------------------------------------------------------===//
+//
+// 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, c++20
+
+#include <algorithm>
+#include <benchmark/benchmark.h>
+#include <vector>
+
+static void bm_ranges_copy(benchmark::State& state, bool aligned) {
+  auto n = state.range();
+  std::vector<bool> in(n, true);
+  std::vector<bool> out(aligned ? n : n + 8);
+  benchmark::DoNotOptimize(&in);
+  auto dst = aligned ? out.begin() : out.begin() + 4;
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(std::ranges::copy(in, dst));
+    benchmark::DoNotOptimize(&out);
+  }
+}
+
+static void bm_ranges_copy_n(benchmark::State& state, bool aligned) {
+  auto n = state.range();
+  std::vector<bool> in(n, true);
+  std::vector<bool> out(aligned ? n : n + 8);
+  benchmark::DoNotOptimize(&in);
+  auto src = in.begin();
+  auto dst = aligned ? out.begin() : out.begin() + 4;
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(std::ranges::copy_n(src, n, dst));
+    benchmark::DoNotOptimize(&out);
+  }
+}
+
+static void bm_copy(benchmark::State& state, bool aligned) {
+  auto n = state.range();
+  std::vector<bool> in(n, true);
+  std::vector<bool> out(aligned ? n : n + 8);
+  benchmark::DoNotOptimize(&in);
+  auto beg = in.begin();
+  auto end = in.end();
+  auto dst = aligned ? out.begin() : out.begin() + 4;
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(std::copy(beg, end, dst));
+    benchmark::DoNotOptimize(&out);
+  }
+}
+
+static void bm_copy_n(benchmark::State& state, bool aligned) {
+  auto n = state.range();
+  std::vector<bool> in(n, true);
+  std::vector<bool> out(aligned ? n : n + 8);
+  benchmark::DoNotOptimize(&in);
+  auto src = in.begin();
+  auto dst = aligned ? out.begin() : out.begin() + 4;
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(std::copy_n(src, n, dst));
+    benchmark::DoNotOptimize(&out);
+  }
+}
+
+static void bm_ranges_copy_aligned(benchmark::State& state) { bm_ranges_copy(state, true); }
+static void bm_ranges_copy_unaligned(benchmark::State& state) { bm_ranges_copy(state, false); }
+static void bm_ranges_copy_n_aligned(benchmark::State& state) { bm_ranges_copy_n(state, true); }
+static void bm_ranges_copy_n_unaligned(benchmark::State& state) { bm_ranges_copy_n(state, false); }
+
+static void bm_copy_aligned(benchmark::State& state) { bm_copy(state, true); }
+static void bm_copy_unaligned(benchmark::State& state) { bm_copy(state, false); }
+static void bm_copy_n_aligned(benchmark::State& state) { bm_copy_n(state, true); }
+static void bm_copy_n_unaligned(benchmark::State& state) { bm_copy_n(state, false); }
+
+// Test the range version of std::copy for vector<bool>::iterator
+BENCHMARK(bm_ranges_copy_aligned)->Range(8, 1 << 16)->DenseRange(102400, 204800, 4096);
+BENCHMARK(bm_ranges_copy_n_aligned)->Range(8, 1 << 20);
+BENCHMARK(bm_ranges_copy_unaligned)->Range(8, 1 << 20);
+BENCHMARK(bm_ranges_copy_n_unaligned)->Range(8, 1 << 20);
+
+// Test the iterator-pair version of std::copy for vector<bool>::iterator
+BENCHMARK(bm_copy_aligned)->Range(8, 1 << 20);
+BENCHMARK(bm_copy_n_aligned)->Range(8, 1 << 20);
+BENCHMARK(bm_copy_unaligned)->Range(8, 1 << 20);
+BENCHMARK(bm_copy_n_unaligned)->Range(8, 1 << 20);
----------------
winner245 wrote:

Yes, I have renamed the benchmarks to include `_vb_` to make it clear that they are measuring `vector<bool>` operations. For example, `bm_ranges_copy_aligned` is renamed to `bm_ranges_copy_vb_aligned`.


https://github.com/llvm/llvm-project/pull/121013