Skip chash computation in insert/emplace if the unconstrained hash matches.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@276549 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/benchmarks/ContainerBenchmarks.hpp b/benchmarks/ContainerBenchmarks.hpp
index d6107f6..8321caf 100644
--- a/benchmarks/ContainerBenchmarks.hpp
+++ b/benchmarks/ContainerBenchmarks.hpp
@@ -34,6 +34,38 @@
}
}
+
+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/benchmarks/GenerateInput.hpp b/benchmarks/GenerateInput.hpp
index 5ddda76..49fb48d 100644
--- a/benchmarks/GenerateInput.hpp
+++ b/benchmarks/GenerateInput.hpp
@@ -130,4 +130,11 @@
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/benchmarks/unordered_set_operations.bench.cpp b/benchmarks/unordered_set_operations.bench.cpp
index ab737c1..8c44638 100644
--- a/benchmarks/unordered_set_operations.bench.cpp
+++ b/benchmarks/unordered_set_operations.bench.cpp
@@ -265,4 +265,42 @@
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()
diff --git a/include/__hash_table b/include/__hash_table
index 0210c6f..6a0e6fe 100644
--- a/include/__hash_table
+++ b/include/__hash_table
@@ -1961,7 +1961,7 @@
if (__nd != nullptr)
{
for (__nd = __nd->__next_; __nd != nullptr &&
- __constrain_hash(__nd->__hash(), __bc) == __chash;
+ (__nd->__hash() == __hash || __constrain_hash(__nd->__hash(), __bc) == __chash);
__nd = __nd->__next_)
{
if (key_eq()(__nd->__upcast()->__value_, __k))