[libcxx-commits] [libcxx] [libc++] Optimize __tree copy/move constructor/assignment with allocator (PR #163558)

[Nikolas Klauser via libcxx-commits]

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@@ -1426,46 +1417,85 @@ private:
     return __new_node_ptr;
   }
 
+  _LIBCPP_HIDE_FROM_ABI __node_pointer __copy_construct_tree(__node_pointer __src) {
+    return __construct_from_tree(__src, [this](const value_type& __val) { return __construct_node(__val); });
+  }
+
+  template <class _ValueT = _Tp, __enable_if_t<__is_tree_value_type_v<_ValueT>, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI __node_pointer __move_construct_tree(__node_pointer __src) {
+    return __construct_from_tree(__src, [this](value_type& __val) {
+      return __construct_node(const_cast<key_type&&>(__val.first), std::move(__val.second));
+    });
+  }
+
+  template <class _ValueT = _Tp, __enable_if_t<!__is_tree_value_type_v<_ValueT>, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI __node_pointer __move_construct_tree(__node_pointer __src) {
+    return __construct_from_tree(__src, [this](value_type& __val) { return __construct_node(std::move(__val)); });
+  }
+
+  template <class _Assignment, class _ConstructionAlg>
   // This copy assignment will always produce a correct red-black-tree assuming the incoming tree is correct, since our
   // own tree is a red-black-tree and the incoming tree is a red-black-tree. The invariants of a red-black-tree are
   // temporarily not met until all of the incoming red-black tree is copied.
 #ifdef _LIBCPP_COMPILER_CLANG_BASED // FIXME: GCC complains about not being able to always_inline a recursive function
   _LIBCPP_HIDE_FROM_ABI
 #endif
-  __node_pointer
-  __copy_assign_tree(__node_pointer __dest, __node_pointer __src) {
+  __node_pointer __assign_from_tree(
+      __node_pointer __dest, __node_pointer __src, _Assignment __assign, _ConstructionAlg __continue_with_construct) {
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philnik777 wrote:

I continue the copy by constructing the elements instead of assigning. Not sure if there is a better name

https://github.com/llvm/llvm-project/pull/163558