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re PR libstdc++/61667 (setting max_load_factor of unordered_map cause buckets shrink)

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2014-08-09  François Dumont  <fdumont@gcc.gnu.org>

	PR libstdc++/61667
	* include/bits/hashtable.h (_Hashtable<>::__rehash_policy): Use
	_M_need_rehash to initialize the rehash policy and check if a rehash is
	needed.
	* testsuite/23_containers/unordered_map/modifiers/61667.cc: New.

From-SVN: r213775
This commit is contained in:
François Dumont 2014-08-09 08:00:59 +00:00
parent b5bdf598f9
commit 013078982d
3 changed files with 56 additions and 4 deletions
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8
libstdc++-v3/ChangeLog
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@ -1,3 +1,11 @@
2014-08-09 François Dumont <fdumont@gcc.gnu.org>
PR libstdc++/61667
* include/bits/hashtable.h (_Hashtable<>::__rehash_policy): Use
_M_need_rehash to initialize the rehash policy and check if a rehash is
needed.
* testsuite/23_containers/unordered_map/modifiers/61667.cc: New.
2014-08-07 Jonathan Wakely <jwakely@redhat.com>
* include/bits/stl_list.h (_List_base::_List_base(_List_base&&)):

8
libstdc++-v3/include/bits/hashtable.h
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@ -1281,10 +1281,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
__rehash_policy(const _RehashPolicy& __pol)
{
size_type __n_bkt = __pol._M_bkt_for_elements(_M_element_count);
__n_bkt = __pol._M_next_bkt(__n_bkt);
if (__n_bkt != _M_bucket_count)
_M_rehash(__n_bkt, _M_rehash_policy._M_state());
auto __do_rehash =
__pol._M_need_rehash(_M_bucket_count, _M_element_count, 0);
if (__do_rehash.first)
_M_rehash(__do_rehash.second, _M_rehash_policy._M_state());
_M_rehash_policy = __pol;
}

44
libstdc++-v3/testsuite/23_containers/unordered_map/modifiers/61667.cc Normal file
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@ -0,0 +1,44 @@
// { dg-options "-std=gnu++11" }
// Copyright (C) 2011-2014 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/>.
#include <unordered_map>
#include <testsuite_hooks.h>
bool test __attribute__((unused)) = true;
void test01()
{
std::unordered_map<int, int> um(20);
std::size_t bkt_count = um.bucket_count();
um.max_load_factor(um.max_load_factor());
VERIFY( um.bucket_count() >= bkt_count );
um.max_load_factor(um.max_load_factor() * 2.f);
VERIFY( um.bucket_count() >= bkt_count );
}
int main()
{
test01();
return 0;
}