better benchmark. It's now the same speed as abseil

Author: martinus

include/ankerl/unordered_dense.h

@@ -334,7 +334,7 @@ struct tuple_hash_helper {
     // If it isn't an integral we need to hash it.
     template <typename Arg>
     [[nodiscard]] constexpr static auto to64(Arg const& arg) -> uint64_t {
-        if constexpr (std::is_integral_v<Arg>) {
+        if constexpr (std::is_integral_v<Arg> || std::is_enum_v<Arg>) {
             return static_cast<uint64_t>(arg);
         } else {
             return hash<Arg>{}(arg);

scripts/build.py

@@ -7,10 +7,10 @@
 
 cmd_and_dir = [
     # needs honggfuzz installed
-    ['env', 'CXX_LD=mold', 'CXX=ccache g++',     'meson', 'setup', '--buildtype', 'release', '-Dcpp_std=c++17', 'builddir/gcc_cpp17_release'],
+    ['env', 'CXX_LD=mold', 'CXX=ccache clang++', 'meson', 'setup', '--buildtype', 'debug',   '-Dcpp_std=c++17', 'builddir/clang_cpp17_debug'],
     ['env', 'CXX_LD=mold', 'CXX=ccache clang++', 'meson', 'setup', '--buildtype', 'release', '-Dcpp_std=c++17', 'builddir/clang_cpp17_release'],
+    ['env', 'CXX_LD=mold', 'CXX=ccache g++',     'meson', 'setup', '--buildtype', 'release', '-Dcpp_std=c++17', 'builddir/gcc_cpp17_release'],
     ['env', 'CXX_LD=mold', 'CXX=ccache hfuzz-clang++ -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION', 'meson', 'setup', '--buildtype', 'release', '-Dcpp_std=c++17', 'builddir/hfuzz-clang_cpp17_release'],
-    ['env', 'CXX_LD=mold', 'CXX=ccache clang++', 'meson', 'setup', '--buildtype', 'debug',   '-Dcpp_std=c++17', 'builddir/clang_cpp17_debug'],
     ['env', 'CXX_LD=mold', 'CXX=ccache g++',     'meson', 'setup', '--buildtype', 'debug',   '-Dcpp_std=c++17', 'builddir/gcc_cpp17_debug'],
 
     # 32bit. Install lib32-clang

test/unit/tuple_hash.cpp

@@ -45,13 +45,26 @@ TEST_CASE("tuple_hash_with_stringview") {
     REQUIRE(h1 != h2);
 }
 
+// #include <absl/hash/hash.h>
+
 TEST_CASE("bench_tuple_hash" * doctest::test_suite("bench")) {
-    using T = std::tuple<char, int, uint16_t, std::byte, uint64_t>;
+    using T = std::tuple<uint8_t, int, uint16_t, uint64_t>;
+
+    auto vecs = std::vector<T>(100);
+    auto rng = ankerl::nanobench::Rng(123);
+    for (auto& v : vecs) {
+        std::get<0>(v) = static_cast<uint8_t>(rng());
+        std::get<1>(v) = static_cast<int>(rng());
+        std::get<2>(v) = static_cast<uint16_t>(rng());
+        std::get<3>(v) = static_cast<uint64_t>(rng());
+    }
 
-    auto h = uint64_t{};
-    auto t = std::tuple<char, int, uint16_t, std::byte, uint64_t>{};
-    ankerl::nanobench::Bench().run("ankerl hash", [&] {
-        h += ankerl::unordered_dense::hash<T>{}(t);
-        ++std::get<4>(t);
+    uint64_t h = 0;
+    ankerl::nanobench::Bench().batch(vecs.size()).run("ankerl hash", [&] {
+        for (auto const& v : vecs) {
+            h += ankerl::unordered_dense::hash<T>{}(v);
+            // h += absl::Hash<T>{}(v);
+        }
     });
+    ankerl::nanobench::doNotOptimizeAway(h);
 }