re PR libstdc++/87872 (debug list::splice should not call _M_transfer_from_if on self-splices)

2018-11-06  John Bytheway  <jbytheway@gmail.com>

	PR libstdc++/87872
	* include/debug/safe_sequence.tcc
	(_Safe_sequence<>::_M_transfer_from_if): Skip transfer to self.

From-SVN: r265851

libstdc++-v3/ChangeLog

+2018-11-06  John Bytheway  <jbytheway@gmail.com>
+
+	PR libstdc++/87872
+	* include/debug/safe_sequence.tcc
+	(_Safe_sequence<>::_M_transfer_from_if): Skip transfer to self.
+
 2018-10-31  Joseph Myers  <joseph@codesourcery.com>
 
 	PR bootstrap/82856

libstdc++-v3/include/debug/safe_sequence.tcc

@@ -68,6 +68,9 @@ namespace __gnu_debug
       _Safe_sequence<_Sequence>::
       _M_transfer_from_if(_Safe_sequence& __from, _Predicate __pred)
       {
+	if (this == std::__addressof(__from))
+	  return;
+
 	typedef typename _Sequence::iterator iterator;
 	typedef typename _Sequence::const_iterator const_iterator;