forward_list.h (_Fwd_list_base(const _Node_alloc_type&)): Change parameter to rvalue-reference.

* include/bits/forward_list.h
	(_Fwd_list_base(const _Node_alloc_type&)): Change parameter to
	rvalue-reference.
	(_Fwd_list_base(_Fwd_list_base&&, const _Node_alloc_type&)): Likewise.
	(forward_list(const _Alloc&)): Split default constructor out to
	separate function.
	(forward_list(forward_list&&, const _Alloc&)): Move elements if base
	class didn't do so.
	(forward_list::_M_move_assign(forward_list&&, true_type)): Replace
	swap call with two assignments.
	* include/bits/forward_list.tcc
	(_Fwd_list_base(_Fwd_list_base&&, const _Node_alloc_type&)): Don't
	move elements when allocators are not equal.
	* include/debug/forward_list (forward_list(const allocator_type&)):
	Split default constructor out to separate function.
	* include/profile/forward_list (forward_list(const _Alloc&)):
	Likewise.

From-SVN: r224566

libstdc++-v3/ChangeLog

@@ -1,5 +1,23 @@
 2015-06-17  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/bits/forward_list.h
+	(_Fwd_list_base(const _Node_alloc_type&)): Change parameter to
+	rvalue-reference.
+	(_Fwd_list_base(_Fwd_list_base&&, const _Node_alloc_type&)): Likewise.
+	(forward_list(const _Alloc&)): Split default constructor out to
+	separate function.
+	(forward_list(forward_list&&, const _Alloc&)): Move elements if base
+	class didn't do so.
+	(forward_list::_M_move_assign(forward_list&&, true_type)): Replace
+	swap call with two assignments.
+	* include/bits/forward_list.tcc
+	(_Fwd_list_base(_Fwd_list_base&&, const _Node_alloc_type&)): Don't
+	move elements when allocators are not equal.
+	* include/debug/forward_list (forward_list(const allocator_type&)):
+	Split default constructor out to separate function.
+	* include/profile/forward_list (forward_list(const _Alloc&)):
+	Likewise.
+
 	* include/bits/forward_list.h (forward_list::_M_get_Node_allocator):
 	Remove unnecessary uses of operator& and static_cast.
 	* include/bits/forward_list.tcc

libstdc++-v3/include/bits/forward_list.h

@@ -314,10 +314,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       _Fwd_list_base()
       : _M_impl() { }
 
-      _Fwd_list_base(const _Node_alloc_type& __a)
+      _Fwd_list_base(_Node_alloc_type&& __a)
-      : _M_impl(__a) { }
+      : _M_impl(std::move(__a)) { }
 
-      _Fwd_list_base(_Fwd_list_base&& __lst, const _Node_alloc_type& __a);
+      _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a);
 
       _Fwd_list_base(_Fwd_list_base&& __lst)
       : _M_impl(std::move(__lst._M_get_Node_allocator()))
@@ -433,15 +433,24 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
       // 23.3.4.2 construct/copy/destroy:
 
+      /**
+       *  @brief  Creates a %forward_list with no elements.
+       */
+      forward_list()
+      noexcept(is_nothrow_default_constructible<_Node_alloc_type>::value)
+      : _Base()
+      { }
+
       /**
        *  @brief  Creates a %forward_list with no elements.
        *  @param  __al  An allocator object.
        */
       explicit
-      forward_list(const _Alloc& __al = _Alloc())
+      forward_list(const _Alloc& __al) noexcept
       : _Base(_Node_alloc_type(__al))
       { }
 
+
       /**
        *  @brief  Copy constructor with allocator argument.
        *  @param  __list  Input list to copy.
@@ -459,7 +468,13 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       forward_list(forward_list&& __list, const _Alloc& __al)
       noexcept(_Node_alloc_traits::_S_always_equal())
       : _Base(std::move(__list), _Node_alloc_type(__al))
-      { }
+      {
+	// If __list is not empty it means its allocator is not equal to __a,
+	// so we need to move from each element individually.
+	insert_after(cbefore_begin(),
+		     std::__make_move_if_noexcept_iterator(__list.begin()),
+		     std::__make_move_if_noexcept_iterator(__list.end()));
+      }
 
       /**
        *  @brief  Creates a %forward_list with default constructed elements.
@@ -1248,8 +1263,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       _M_move_assign(forward_list&& __list, std::true_type) noexcept
       {
         clear();
-        std::swap(this->_M_impl._M_head._M_next,
+        this->_M_impl._M_head._M_next = __list._M_impl._M_head._M_next;
-                  __list._M_impl._M_head._M_next);
+        __list._M_impl._M_head._M_next = nullptr;
         std::__alloc_on_move(this->_M_get_Node_allocator(),
                              __list._M_get_Node_allocator());
       }

libstdc++-v3/include/bits/forward_list.tcc

@@ -36,28 +36,16 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
   template<typename _Tp, typename _Alloc>
     _Fwd_list_base<_Tp, _Alloc>::
-    _Fwd_list_base(_Fwd_list_base&& __lst, const _Node_alloc_type& __a)
+    _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a)
-    : _M_impl(__a)
+    : _M_impl(std::move(__a))
     {
-      if (__lst._M_get_Node_allocator() == __a)
+      if (__lst._M_get_Node_allocator() == _M_get_Node_allocator())
 	{
 	  this->_M_impl._M_head._M_next = __lst._M_impl._M_head._M_next;
 	  __lst._M_impl._M_head._M_next = 0;
 	}
       else
-        {
+	this->_M_impl._M_head._M_next = 0;
-          this->_M_impl._M_head._M_next = 0;
-          _Fwd_list_node_base* __to = &this->_M_impl._M_head;
-          _Node* __curr = static_cast<_Node*>(__lst._M_impl._M_head._M_next);
-
-          while (__curr)
-            {
-              __to->_M_next =
-                _M_create_node(std::move_if_noexcept(*__curr->_M_valptr()));
-              __to = __to->_M_next;
-              __curr = static_cast<_Node*>(__curr->_M_next);
-            }
-        }
     }
 
   template<typename _Tp, typename _Alloc>

libstdc++-v3/include/debug/forward_list

@@ -204,8 +204,11 @@ namespace __debug
       typedef typename _Base::const_pointer	const_pointer;
 
       // 23.2.3.1 construct/copy/destroy:
+
+      forward_list() = default;
+
       explicit
-      forward_list(const allocator_type& __al = allocator_type())
+      forward_list(const allocator_type& __al) noexcept
       : _Base(__al) { }
 
       forward_list(const forward_list& __list, const allocator_type& __al)

libstdc++-v3/include/profile/forward_list

@@ -51,8 +51,11 @@ namespace __profile
       typedef typename _Base::const_iterator	const_iterator;
 
       // 23.2.3.1 construct/copy/destroy:
+
+      forward_list() = default;
+
       explicit
-      forward_list(const _Alloc& __al = _Alloc())
+      forward_list(const _Alloc& __al) noexcept
       : _Base(__al) { }
 
       forward_list(const forward_list& __list, const _Alloc& __al)