Minor optimization in vector<>::make_space_for_insert().

psiha · Sep 17, 2024 · 510fc09 · 510fc09
1 parent cb49c28
commit 510fc09
Showing 1 changed file with 12 additions and 5 deletions.
diff --git a/include/psi/vm/vector.hpp b/include/psi/vm/vector.hpp
@@ -1185,11 +1185,18 @@ class vector
         auto const current_size  { size() };
         auto const new_size      { current_size + n };
         storage_.expand( to_byte_sz( new_size ) );
-        auto const elements_to_move                       { static_cast<size_type>( current_size - position_index ) };
-        auto const elements_to_move_to_uninitialized_space{ n };
-        auto const elements_to_move_to_the_current_end    { static_cast<size_type>( elements_to_move - elements_to_move_to_uninitialized_space ) };
-        std::uninitialized_move_n( nth( current_size - elements_to_move_to_uninitialized_space ),                       elements_to_move_to_uninitialized_space, nth( current_size       ) );
-        std::move                ( nth( position_index                                         ), nth( position_index + elements_to_move_to_the_current_end )  , nth( position_index + n ) );
+        if constexpr ( is_trivially_moveable<T> )
+        {
+            std::move( nth( position_index ), nth( position_index + n ), nth( position_index + n ) );
+        }
+        else // future support for generic types
+        {
+            auto const elements_to_move                       { static_cast<size_type>( current_size - position_index ) };
+            auto const elements_to_move_to_uninitialized_space{ n };
+            auto const elements_to_move_to_the_current_end    { static_cast<size_type>( elements_to_move - elements_to_move_to_uninitialized_space ) };
+            std::uninitialized_move_n( nth( current_size - elements_to_move_to_uninitialized_space ),                       elements_to_move_to_uninitialized_space, nth( current_size       ) );
+            std::move                ( nth( position_index                                         ), nth( position_index + elements_to_move_to_the_current_end )  , nth( position_index + n ) );
+        }
         return nth( position_index );
     }
 }; // class vector