Make sure the return value of malloc_allocator::allocate is zero-initialized so...

	Make sure the return value of malloc_allocator::allocate
	is zero-initialized so that checking it for non-zero works
	later.
	* include/ext/malloc_allocator.h (malloc_allocator::allocate):
	Initialize the return value.
	* testsuite/ext/malloc_allocator/sanity.cc: New.

From-SVN: r241212

libstdc++-v3/ChangeLog

+2016-10-16  Ville Voutilainen  <ville.voutilainen@gmail.com>
+
+	Make sure the return value of malloc_allocator::allocate
+	is zero-initialized so that checking it for non-zero works
+	later.
+	* include/ext/malloc_allocator.h (malloc_allocator::allocate):
+	Initialize the return value.
+	* testsuite/ext/malloc_allocator/sanity.cc: New.
+
 2016-10-14  Eelis van der Weegen  <eelis@eelis.net>
 
 	* include/bits/stl_algo.h (shuffle): Extract two random numbers from

libstdc++-v3/include/ext/malloc_allocator.h

@@ -101,7 +101,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	if (__n > this->max_size())
 	  std::__throw_bad_alloc();
 
-	pointer __ret;
+	pointer __ret = 0;
 #if __cpp_aligned_new
 #if __cplusplus > 201402L && _GLIBCXX_HAVE_ALIGNED_ALLOC
 	if (alignof(_Tp) > alignof(std::max_align_t))

libstdc++-v3/testsuite/ext/malloc_allocator/sanity.cc

+// Copyright (C) 2016 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-do run { target c++11 } }
+
+#include <map>
+#include <vector>
+#include <ext/malloc_allocator.h>
+
+int main()
+{
+  std::map<int, int, std::less<int>,
+	   __gnu_cxx::malloc_allocator<std::pair<int, int> > > allocs;
+  allocs[9] = 3;
+  std::vector<int, __gnu_cxx::malloc_allocator<int>> vec(10);
+  vec[5] = 42;
+}