[libcxx-commits] [libcxx] [libc++] Add benchmarks for partitioning algorithms (PR #127324)

[Nikolas Klauser via libcxx-commits]

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@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <cstddef>
+#include <deque>
+#include <iterator>
+#include <list>
+#include <string>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+#include "../../GenerateInput.h"
+
+auto compute_median(auto first, auto last) {
+  std::vector v(first, last);
+  auto middle = v.begin() + v.size() / 2;
+  std::nth_element(v.begin(), middle, v.end());
+  return *middle;
+}
+
+int main(int argc, char** argv) {
+  auto std_partition = [](auto first, auto last, auto pred) { return std::partition(first, last, pred); };
+
+  auto bm = []<class Container>(std::string name, auto partition) {
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philnik777 wrote:

I think it could be interesting to add a sparse test case, i.e. cases where most of the elements are partitioned, except for a few (maybe 10%) of the elements. I don't know how expensive that will be. If it's too expensive we could leave it disabled for now and only enable it if we modify `partition` in any way.

https://github.com/llvm/llvm-project/pull/127324