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Re: [Bug libstdc++/63500] [4.9/5 Regression] bug in debug version of std::make_move_iterator?


On 15/10/14 22:06 +0200, François Dumont wrote:
On 15/10/2014 13:10, Jonathan Wakely wrote:

I find this much easier to read:

#if __cplusplus < 201103L
    typedef _Is_contiguous_sequence<_Sequence> __tag;
#else
    using __lvalref = std::is_lvalue_reference<
      typename std::iterator_traits<_InputIterator>::reference>;
    using __contiguous = _Is_contiguous_sequence<_Sequence>;
using __tag = typename std::conditional<__lvalref::value, __contiguous,
std::__false_type>::type;
#endif
    return __foreign_iterator_aux3(__it, __other, __other_end, __tag());

It only has one preprocessor condition and it avoids mismatched
parentheses caused by opening the function parameter list once but
closing it twice in two different branches.


That's much better indeed.

Shall we go with this ? Of course we are simply considering that we can't check for foreign iterators when some iterator adapters comes in-between. I hope one day to detect invalid usages even in this context.

2014-10-16  François Dumont  <fdumont@gcc.gnu.org>

   PR libstdc++/63500
   * include/debug/functions.h (__foreign_iterator_aux2): Do not check for
   foreign iterators if input iterators returns rvalue reference.
   * testsuite/23_containers/vector/63500.cc: New.

François


As this is a regression it should go on the 4.9 branch too.

Index: include/debug/functions.h
===================================================================
--- include/debug/functions.h	(revision 216279)
+++ include/debug/functions.h	(working copy)
@@ -34,7 +34,7 @@
					  // _Iter_base
#include <bits/cpp_type_traits.h>	  // for __is_integer
#include <bits/move.h>                    // for __addressof and addressof
-# include <bits/stl_function.h>		  // for less
+#include <bits/stl_function.h>		  // for less
#if __cplusplus >= 201103L
# include <type_traits>			  // for is_lvalue_reference and __and_
#endif
@@ -252,8 +252,16 @@
			    const _InputIterator& __other,
			    const _InputIterator& __other_end)
    {
-      return __foreign_iterator_aux3(__it, __other, __other_end,
-				     _Is_contiguous_sequence<_Sequence>());
+#if __cplusplus < 201103L
+      typedef _Is_contiguous_sequence<_Sequence> __tag;
+#else
+      using __lvalref = std::is_lvalue_reference<
+	typename std::iterator_traits<_InputIterator>::reference>;
+      using __contiguous = _Is_contiguous_sequence<_Sequence>;
+      using __tag = typename std::conditional<__lvalref::value, __contiguous,
+					      std::__false_type>::type;
+#endif
+      return __foreign_iterator_aux3(__it, __other, __other_end, __tag());
    }

  /* Handle the case where we aren't really inserting a range after all */
Index: testsuite/23_containers/vector/63500.cc
===================================================================
--- testsuite/23_containers/vector/63500.cc	(revision 0)
+++ testsuite/23_containers/vector/63500.cc	(working copy)
@@ -0,0 +1,39 @@
+// -*- C++ -*-
+
+// Copyright (C) 2014 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++11" }
+// { dg-do compile }
+
+#include <memory>
+#include <iterator>
+#include <debug/vector>
+
+class Foo
+{};
+
+void
+test01()
+{
+  __gnu_debug::vector<std::unique_ptr<Foo>> v;
+  __gnu_debug::vector<std::unique_ptr<Foo>> w;
+
+  v.insert(end(v),
+	   make_move_iterator(begin(w)),
+	   make_move_iterator(end(w)));
+}


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