Skip chash computation in insert/emplace if the unconstrained hash matches.

llvm-svn: 276549

3 files changed, 77 insertions, 0 deletions

diff --git a/libcxx/benchmarks/ContainerBenchmarks.hpp b/libcxx/benchmarks/ContainerBenchmarks.hpp
index d6107f6228a..8321caf3385 100644
--- a/libcxx/benchmarks/ContainerBenchmarks.hpp
+++ b/libcxx/benchmarks/ContainerBenchmarks.hpp
@@ -34,6 +34,38 @@ void BM_InsertValueRehash(benchmark::State& st, Container c, GenInputs gen) {
     }
 }
 
+
+template <class Container, class GenInputs>
+void BM_InsertDuplicate(benchmark::State& st, Container c, GenInputs gen) {
+    auto in = gen(st.range_x());
+    const auto end = in.end();
+    c.insert(in.begin(), in.end());
+    benchmark::DoNotOptimize(&c);
+    benchmark::DoNotOptimize(&in);
+    while (st.KeepRunning()) {
+        for (auto it = in.begin(); it != end; ++it) {
+            benchmark::DoNotOptimize(&(*c.insert(*it).first));
+        }
+        benchmark::ClobberMemory();
+    }
+}
+
+
+template <class Container, class GenInputs>
+void BM_EmplaceDuplicate(benchmark::State& st, Container c, GenInputs gen) {
+    auto in = gen(st.range_x());
+    const auto end = in.end();
+    c.insert(in.begin(), in.end());
+    benchmark::DoNotOptimize(&c);
+    benchmark::DoNotOptimize(&in);
+    while (st.KeepRunning()) {
+        for (auto it = in.begin(); it != end; ++it) {
+            benchmark::DoNotOptimize(&(*c.emplace(*it).first));
+        }
+        benchmark::ClobberMemory();
+    }
+}
+
 template <class Container, class GenInputs>
 static void BM_Find(benchmark::State& st, Container c, GenInputs gen) {
     auto in = gen(st.range_x());
diff --git a/libcxx/benchmarks/GenerateInput.hpp b/libcxx/benchmarks/GenerateInput.hpp
index 5ddda76afc5..49fb48d9c9e 100644
--- a/libcxx/benchmarks/GenerateInput.hpp
+++ b/libcxx/benchmarks/GenerateInput.hpp
@@ -130,4 +130,11 @@ inline std::vector<std::string> getReverseSortedStringInputs(size_t N) {
     return inputs;
 }
 
+inline std::vector<const char*> getRandomCStringInputs(size_t N) {
+    static std::vector<std::string> inputs = getRandomStringInputs(N);
+    std::vector<const char*> cinputs;
+    for (auto const& str : inputs)
+        cinputs.push_back(str.c_str());
+    return cinputs;
+}
 #endif // BENCHMARK_GENERATE_INPUT_HPP
diff --git a/libcxx/benchmarks/unordered_set_operations.bench.cpp b/libcxx/benchmarks/unordered_set_operations.bench.cpp
index ab737c1ee7d..8c4463865d5 100644
--- a/libcxx/benchmarks/unordered_set_operations.bench.cpp
+++ b/libcxx/benchmarks/unordered_set_operations.bench.cpp
@@ -265,4 +265,42 @@ BENCHMARK_CAPTURE(BM_FindRehash,
     std::unordered_set<std::string>{},
     getRandomStringInputs)->Arg(TestNumInputs);
 
+///////////////////////////////////////////////////////////////////////////////
+BENCHMARK_CAPTURE(BM_InsertDuplicate,
+    unordered_set_int,
+    std::unordered_set<int>{},
+    getRandomIntegerInputs<int>)->Arg(TestNumInputs);
+BENCHMARK_CAPTURE(BM_InsertDuplicate,
+    unordered_set_string,
+    std::unordered_set<std::string>{},
+    getRandomStringInputs)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_EmplaceDuplicate,
+    unordered_set_int,
+    std::unordered_set<int>{},
+    getRandomIntegerInputs<int>)->Arg(TestNumInputs);
+BENCHMARK_CAPTURE(BM_EmplaceDuplicate,
+    unordered_set_string,
+    std::unordered_set<std::string>{},
+    getRandomStringInputs)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_InsertDuplicate,
+    unordered_set_int_insert_arg,
+    std::unordered_set<int>{},
+    getRandomIntegerInputs<int>)->Arg(TestNumInputs);
+BENCHMARK_CAPTURE(BM_InsertDuplicate,
+    unordered_set_string_insert_arg,
+    std::unordered_set<std::string>{},
+    getRandomStringInputs)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_EmplaceDuplicate,
+    unordered_set_int_insert_arg,
+    std::unordered_set<int>{},
+    getRandomIntegerInputs<unsigned>)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_EmplaceDuplicate,
+    unordered_set_string_arg,
+    std::unordered_set<std::string>{},
+    getRandomCStringInputs)->Arg(TestNumInputs);
+
 BENCHMARK_MAIN()