edc3dc6abd
As a follow-up to #121013 (which focused on `std::ranges::copy`), this PR optimizes the performance of `std::ranges::copy_backward` for `vector<bool>::iterator`, addressing a subtask outlined in issue #64038. The optimizations yield performance improvements of up to 2000x for aligned copies and 60x for unaligned copies.
56 lines
2.2 KiB
C++
56 lines
2.2 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, c++20
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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_copy_backward_vb(benchmark::State& state, bool aligned) {
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auto n = state.range();
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std::vector<bool> in(n, true);
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std::vector<bool> out(aligned ? n : n + 8);
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benchmark::DoNotOptimize(&in);
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auto dst = aligned ? out.end() : out.end() - 4;
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for (auto _ : state) {
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benchmark::DoNotOptimize(std::ranges::copy_backward(in, dst));
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benchmark::DoNotOptimize(&out);
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}
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}
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static void bm_copy_backward_vb(benchmark::State& state, bool aligned) {
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auto n = state.range();
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std::vector<bool> in(n, true);
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std::vector<bool> out(aligned ? n : n + 8);
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benchmark::DoNotOptimize(&in);
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auto beg = in.begin();
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auto end = in.end();
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auto dst = aligned ? out.end() : out.end() - 4;
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for (auto _ : state) {
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benchmark::DoNotOptimize(std::copy_backward(beg, end, dst));
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benchmark::DoNotOptimize(&out);
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}
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}
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static void bm_ranges_copy_backward_vb_aligned(benchmark::State& state) { bm_ranges_copy_backward_vb(state, true); }
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static void bm_ranges_copy_backward_vb_unaligned(benchmark::State& state) { bm_ranges_copy_backward_vb(state, false); }
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static void bm_copy_backward_vb_aligned(benchmark::State& state) { bm_copy_backward_vb(state, true); }
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static void bm_copy_backward_vb_unaligned(benchmark::State& state) { bm_copy_backward_vb(state, false); }
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// Test std::ranges::copy_backward for vector<bool>::iterator
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BENCHMARK(bm_ranges_copy_backward_vb_aligned)->Range(8, 1 << 16)->DenseRange(102400, 204800, 4096);
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BENCHMARK(bm_ranges_copy_backward_vb_unaligned)->Range(8, 1 << 20);
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// Test std::copy_backward for vector<bool>::iterator
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BENCHMARK(bm_copy_backward_vb_aligned)->Range(8, 1 << 20);
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BENCHMARK(bm_copy_backward_vb_unaligned)->Range(8, 1 << 20);
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BENCHMARK_MAIN();
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