[Bug libstdc++/108554] Warning "null pointer dereferece" raised when extracting a unique_ptr from a map and any "-O" flag

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108554

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-01-26
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This patch fixes it:

--- a/libstdc++-v3/include/bits/stl_tree.h
+++ b/libstdc++-v3/include/bits/stl_tree.h
@@ -405,12 +405,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _Base_ptr _M_node;
     };

+  __attribute__((__nonnull__))
   void
   _Rb_tree_insert_and_rebalance(const bool __insert_left,
                                _Rb_tree_node_base* __x,
                                _Rb_tree_node_base* __p,
                                _Rb_tree_node_base& __header) throw ();

+  __attribute__((__nonnull__,__returns_nonnull__))
   _Rb_tree_node_base*
   _Rb_tree_rebalance_for_erase(_Rb_tree_node_base* const __z,
                               _Rb_tree_node_base& __header) throw ();