Remove redundant benchmark for search_n

Author: ldionne

libcxx/test/benchmarks/algorithms/nonmodifying/search_n.bench.cpp

@@ -38,7 +38,7 @@ int main(int argc, char** argv) {
     });
   };
 
-  // Benchmark {std,ranges}::search_n where the needle is never found
+  // Benchmark {std,ranges}::search_n where the needle is never found (worst case).
   {
     auto bm = []<class Container>(std::string name, auto search_n) {
       benchmark::RegisterBenchmark(
@@ -81,58 +81,6 @@ int main(int argc, char** argv) {
     bm.operator()<std::list<int>>("rng::search_n(list<int>, pred) (no match)", ranges_search_n_pred);
   }
 
-  // Benchmark {std,ranges}::search_n where we intersperse "near matches" inside the haystack
-  {
-    auto bm = []<class Container>(std::string name, auto search_n) {
-      benchmark::RegisterBenchmark(
-          name,
-          [search_n](auto& st) {
-            std::size_t const size = st.range(0);
-            using ValueType        = typename Container::value_type;
-            ValueType x            = Generate<ValueType>::random();
-            ValueType y            = random_different_from({x});
-            Container haystack(size, x);
-            std::size_t n = size / 10; // needle size is 10% of the haystack
-            assert(n > 0);
-
-            // intersperse near-matches inside the haystack
-            {
-              auto first = haystack.begin();
-              for (int i = 0; i != 10; ++i) {
-                first = std::fill_n(first, n - 1, y);
-                ++first; // this causes the subsequence not to match because it has length n-1
-              }
-            }
-
-            for ([[maybe_unused]] auto _ : st) {
-              benchmark::DoNotOptimize(haystack);
-              benchmark::DoNotOptimize(n);
-              benchmark::DoNotOptimize(y);
-              auto result = search_n(haystack.begin(), haystack.end(), n, y);
-              benchmark::DoNotOptimize(result);
-            }
-          })
-          ->Arg(1000) // non power-of-two
-          ->Arg(1024)
-          ->Arg(8192);
-    };
-    // {std,ranges}::search_n
-    bm.operator()<std::vector<int>>("std::search_n(vector<int>) (near matches)", std_search_n);
-    bm.operator()<std::deque<int>>("std::search_n(deque<int>) (near matches)", std_search_n);
-    bm.operator()<std::list<int>>("std::search_n(list<int>) (near matches)", std_search_n);
-    bm.operator()<std::vector<int>>("rng::search_n(vector<int>) (near matches)", std::ranges::search_n);
-    bm.operator()<std::deque<int>>("rng::search_n(deque<int>) (near matches)", std::ranges::search_n);
-    bm.operator()<std::list<int>>("rng::search_n(list<int>) (near matches)", std::ranges::search_n);
-
-    // {std,ranges}::search_n(pred)
-    bm.operator()<std::vector<int>>("std::search_n(vector<int>, pred) (near matches)", std_search_n_pred);
-    bm.operator()<std::deque<int>>("std::search_n(deque<int>, pred) (near matches)", std_search_n_pred);
-    bm.operator()<std::list<int>>("std::search_n(list<int>, pred) (near matches)", std_search_n_pred);
-    bm.operator()<std::vector<int>>("rng::search_n(vector<int>, pred) (near matches)", ranges_search_n_pred);
-    bm.operator()<std::deque<int>>("rng::search_n(deque<int>, pred) (near matches)", ranges_search_n_pred);
-    bm.operator()<std::list<int>>("rng::search_n(list<int>, pred) (near matches)", ranges_search_n_pred);
-  }
-
   benchmark::Initialize(&argc, argv);
   benchmark::RunSpecifiedBenchmarks();
   benchmark::Shutdown();