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a12744ff05
This PR optimizes the performance of `std::ranges::swap_ranges` for `vector<bool>::iterator`, addressing a subtask outlined in issue #64038. The optimizations yield performance improvements of up to **611x** for aligned range swap and **78x** for unaligned range swap comparison. Additionally, comprehensive tests covering up to 4 storage words (256 bytes) with odd and even bit sizes are provided, which validate the proposed optimizations in this patch.
67 lines
2.4 KiB
C++
67 lines
2.4 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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#include <algorithm>
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#include <benchmark/benchmark.h>
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#include <vector>
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static void bm_ranges_swap_ranges_vb_aligned(benchmark::State& state) {
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auto n = state.range();
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std::vector<bool> vec1(n, true);
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std::vector<bool> vec2(n, false);
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for (auto _ : state) {
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benchmark::DoNotOptimize(std::ranges::swap_ranges(vec1, vec2));
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benchmark::DoNotOptimize(&vec1);
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benchmark::DoNotOptimize(&vec2);
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}
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}
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static void bm_ranges_swap_ranges_vb_unaligned(benchmark::State& state) {
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auto n = state.range();
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std::vector<bool> vec1(n, true);
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std::vector<bool> vec2(n + 8, true);
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auto beg1 = std::ranges::begin(vec1);
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auto end1 = std::ranges::end(vec1);
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auto beg2 = std::ranges::begin(vec2) + 4;
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auto end2 = std::ranges::end(vec2) - 4;
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for (auto _ : state) {
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benchmark::DoNotOptimize(std::ranges::swap_ranges(beg1, end1, beg2, end2));
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benchmark::DoNotOptimize(&vec1);
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benchmark::DoNotOptimize(&vec2);
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}
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}
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// Test std::ranges::swap_ranges for vector<bool>::iterator
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BENCHMARK(bm_ranges_swap_ranges_vb_aligned)->RangeMultiplier(2)->Range(8, 1 << 20);
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BENCHMARK(bm_ranges_swap_ranges_vb_unaligned)->Range(8, 1 << 20);
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static void bm_swap_ranges_vb(benchmark::State& state, bool aligned) {
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auto n = state.range();
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std::vector<bool> vec1(n, true);
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std::vector<bool> vec2(aligned ? n : n + 8, true);
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auto beg1 = vec1.begin();
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auto end1 = vec1.end();
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auto beg2 = aligned ? vec2.begin() : vec2.begin() + 4;
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for (auto _ : state) {
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benchmark::DoNotOptimize(std::swap_ranges(beg1, end1, beg2));
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benchmark::DoNotOptimize(&vec1);
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benchmark::DoNotOptimize(&vec2);
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}
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}
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static void bm_swap_ranges_vb_aligned(benchmark::State& state) { bm_swap_ranges_vb(state, true); }
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static void bm_swap_ranges_vb_unaligned(benchmark::State& state) { bm_swap_ranges_vb(state, false); }
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// Test std::swap_ranges for vector<bool>::iterator
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BENCHMARK(bm_swap_ranges_vb_aligned)->Range(8, 1 << 20);
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BENCHMARK(bm_swap_ranges_vb_unaligned)->Range(8, 1 << 20);
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BENCHMARK_MAIN();
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