First half of LWG#2354: 'Unnecessary copying when inserting into maps with braced-init syntax'

llvm-svn: 256859
diff --git a/libcxx/include/__tree b/libcxx/include/__tree
index cb58a90..94565bc 100644
--- a/libcxx/include/__tree
+++ b/libcxx/include/__tree
@@ -909,6 +909,13 @@
     iterator __insert_multi(const value_type& __v);
     iterator __insert_multi(const_iterator __p, const value_type& __v);
 
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    pair<iterator, bool> __insert_unique(        value_type&& __v);
+    iterator __insert_unique(const_iterator __p, value_type&& __v);
+    iterator __insert_multi(                    value_type&& __v);
+    iterator __insert_multi(const_iterator __p, value_type&& __v);
+#endif
+
     pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
     iterator             __node_insert_unique(const_iterator __p,
                                               __node_pointer __nd);
@@ -1730,6 +1737,28 @@
 #endif  // _LIBCPP_HAS_NO_VARIADICS
 
 template <class _Tp, class _Compare, class _Allocator>
+pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
+__tree<_Tp, _Compare, _Allocator>::__insert_unique(value_type&& __v)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<value_type>(__v));
+    pair<iterator, bool> __r = __node_insert_unique(__h.get());
+    if (__r.second)
+        __h.release();
+    return __r;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__insert_unique(const_iterator __p, value_type&& __v)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<value_type>(__v));
+    iterator __r = __node_insert_unique(__p, __h.get());
+    if (__r.__ptr_ == __h.get())
+        __h.release();
+    return __r;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
 template <class _Vp>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__insert_unique(_Vp&& __v)
@@ -1754,6 +1783,28 @@
 }
 
 template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__insert_multi(value_type&& __v)
+{
+    __node_base_pointer __parent;
+    __node_base_pointer& __child = __find_leaf_high(__parent, __v);
+    __node_holder __h = __construct_node(_VSTD::forward<value_type>(__v));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+    return iterator(__h.release());
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__insert_multi(const_iterator __p, value_type&& __v)
+{
+    __node_base_pointer __parent;
+    __node_base_pointer& __child = __find_leaf(__p, __parent, __v);
+    __node_holder __h = __construct_node(_VSTD::forward<value_type>(__v));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+    return iterator(__h.release());
+}
+
+template <class _Tp, class _Compare, class _Allocator>
 template <class _Vp>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__insert_multi(_Vp&& __v)
diff --git a/libcxx/include/map b/libcxx/include/map
index 2416205..87add43 100644
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -126,9 +126,11 @@
     template <class... Args>
         iterator emplace_hint(const_iterator position, Args&&... args);
     pair<iterator, bool> insert(const value_type& v);
+    pair<iterator, bool> insert(      value_type&& v);                                // C++17
     template <class P>
         pair<iterator, bool> insert(P&& p);
     iterator insert(const_iterator position, const value_type& v);
+    iterator insert(const_iterator position,       value_type&& v);                   // C++17
     template <class P>
         iterator insert(const_iterator position, P&& p);
     template <class InputIterator>
@@ -336,9 +338,11 @@
     template <class... Args>
         iterator emplace_hint(const_iterator position, Args&&... args);
     iterator insert(const value_type& v);
+    iterator insert(      value_type&& v);                                            // C++17
     template <class P>
         iterator insert(P&& p);
     iterator insert(const_iterator position, const value_type& v);
+    iterator insert(const_iterator position,       value_type&& v);                   // C++17
     template <class P>
         iterator insert(const_iterator position, P&& p);
     template <class InputIterator>
@@ -1089,6 +1093,17 @@
         insert(const_iterator __p, const value_type& __v)
             {return __tree_.__insert_unique(__p.__i_, __v);}
 
+#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+        insert(     value_type&& __v) {return __tree_.__insert_unique(_VSTD::forward<value_type>(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator
+        insert(const_iterator __p,       value_type&& __v)
+            {return __tree_.__insert_unique(__p.__i_, _VSTD::forward<value_type>(__v));}
+#endif
+
     template <class _InputIterator>
         _LIBCPP_INLINE_VISIBILITY
         void insert(_InputIterator __f, _InputIterator __l)
@@ -1940,6 +1955,15 @@
     iterator insert(const_iterator __p, const value_type& __v)
             {return __tree_.__insert_multi(__p.__i_, __v);}
 
+#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert( value_type&& __v) {return __tree_.__insert_multi(_VSTD::forward<value_type>(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, value_type&& __v)
+            {return __tree_.__insert_multi(__p.__i_, _VSTD::forward<value_type>(__v));}
+#endif
+
     template <class _InputIterator>
         _LIBCPP_INLINE_VISIBILITY
         void insert(_InputIterator __f, _InputIterator __l)