[patch] libstdc++/67707 Leave moved-from std::deque in a valid state

[Jonathan Wakely]

Apparently when adding allocator propagation to std::deque I didn't
read my own comment in this constructor:

     _Deque_base(const allocator_type& __a)
     : _M_impl(__a)
     { /* Caller must initialize map. */ }

This adds the missing initialization.

Tested ppc64le-linux, committed to trunk.

This needs to be backported to gcc-5-branch too.


commit 386b9e9d927e5d0bcca8815b6219581ea58723bf
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Thu Sep 24 16:10:27 2015 +0100

    Leave moved-from std::deque in a valid state
    
    	PR libstdc++/67707
    	* include/bits/stl_deque.h (_Deque_base::_M_move_impl): Initialize
    	empty object.
    	* testsuite/23_containers/deque/allocator/move.cc: Check moved-from
    	deque.

diff --git a/libstdc++-v3/include/bits/stl_deque.h b/libstdc++-v3/include/bits/stl_deque.h
index f674245..f81ffd9 100644
--- a/libstdc++-v3/include/bits/stl_deque.h
+++ b/libstdc++-v3/include/bits/stl_deque.h
@@ -644,6 +644,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 	_Tp_alloc_type __sink __attribute((__unused__)) {std::move(__alloc)};
 	// Create an empty map that allocates using the moved-from allocator.
 	_Deque_base __empty{__alloc};
+	__empty._M_initialize_map(0);
 	// Now safe to modify current allocator and perform non-throwing swaps.
 	_Deque_impl __ret{std::move(_M_get_Tp_allocator())};
 	_M_impl._M_swap_data(__ret);
diff --git a/libstdc++-v3/testsuite/23_containers/deque/allocator/move.cc b/libstdc++-v3/testsuite/23_containers/deque/allocator/move.cc
index c858437..1b8a0e4 100644
--- a/libstdc++-v3/testsuite/23_containers/deque/allocator/move.cc
+++ b/libstdc++-v3/testsuite/23_containers/deque/allocator/move.cc
@@ -36,6 +36,11 @@ void test01()
   VERIFY(1 == v1.get_allocator().get_personality());
   VERIFY(1 == v2.get_allocator().get_personality());
   VERIFY( it == v2.begin() );
+
+  // PR libstdc++/67707
+  VERIFY( v1.size() == 0 );
+  v1 = test_type();
+  VERIFY( v1.size() == 0 );
 }
 
 void test02()
@@ -47,6 +52,11 @@ void test02()
   test_type v2(std::move(v1), alloc_type(2));
   VERIFY(1 == v1.get_allocator().get_personality());
   VERIFY(2 == v2.get_allocator().get_personality());
+
+  // PR libstdc++/67707
+  VERIFY( v1.size() == 0 );
+  v1 = test_type();
+  VERIFY( v1.size() == 0 );
 }
 
 int main()