re PR libstdc++/71181 (Reserving in unordered_map doesn't reserve enough)
2016-06-20 François Dumont <fdumont@gcc.gnu.org> PR libstdc++/71181 * include/tr1/hashtable_policy.h (_Prime_rehash_policy::_M_next_bkt): Make past-the-end iterator dereferenceable to avoid check on lower_bound result. (_Prime_rehash_policy::_M_bkt_for_elements): Call latter. (_Prime_rehash_policy::_M_need_rehash): Likewise. * src/c++11/hashtable_c++0x.cc (_Prime_rehash_policy::_M_next_bkt): Always return a value greater than input value. Set _M_next_resize to max value when reaching highest prime number. * src/shared/hashtable-aux.cc (__prime_list): Add comment about sentinel being now useless. * testsuite/23_containers/unordered_set/hash_policy/71181.cc: New. * testsuite/23_containers/unordered_set/hash_policy/power2_rehash.cc (test02): New. * testsuite/23_containers/unordered_set/hash_policy/prime_rehash.cc: New. * testsuite/23_containers/unordered_set/hash_policy/rehash.cc: Fix indentation. From-SVN: r237617
This commit is contained in:
François Dumont
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3947cf1919
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29dbb034cb
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@ -1,3 +1,23 @@
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2016-06-20 François Dumont <fdumont@gcc.gnu.org>
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PR libstdc++/71181
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* include/tr1/hashtable_policy.h
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(_Prime_rehash_policy::_M_next_bkt): Make past-the-end iterator
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dereferenceable to avoid check on lower_bound result.
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(_Prime_rehash_policy::_M_bkt_for_elements): Call latter.
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(_Prime_rehash_policy::_M_need_rehash): Likewise.
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* src/c++11/hashtable_c++0x.cc (_Prime_rehash_policy::_M_next_bkt):
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Always return a value greater than input value. Set _M_next_resize to
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max value when reaching highest prime number.
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* src/shared/hashtable-aux.cc (__prime_list): Add comment about sentinel
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being now useless.
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* testsuite/23_containers/unordered_set/hash_policy/71181.cc: New.
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* testsuite/23_containers/unordered_set/hash_policy/power2_rehash.cc
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(test02): New.
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* testsuite/23_containers/unordered_set/hash_policy/prime_rehash.cc: New.
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* testsuite/23_containers/unordered_set/hash_policy/rehash.cc:
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Fix indentation.
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2016-06-17 Jonathan Wakely <jwakely@redhat.com>
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PR libstdc++/71545
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@ -420,8 +420,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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_Prime_rehash_policy::
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_M_next_bkt(std::size_t __n) const
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{
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const unsigned long* __p = std::lower_bound(__prime_list, __prime_list
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+ _S_n_primes, __n);
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// Don't include the last prime in the search, so that anything
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// higher than the second-to-last prime returns a past-the-end
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// iterator that can be dereferenced to get the last prime.
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const unsigned long* __p
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= std::lower_bound(__prime_list, __prime_list + _S_n_primes - 1, __n);
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_M_next_resize =
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static_cast<std::size_t>(__builtin_ceil(*__p * _M_max_load_factor));
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return *__p;
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@ -434,11 +437,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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_M_bkt_for_elements(std::size_t __n) const
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{
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const float __min_bkts = __n / _M_max_load_factor;
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const unsigned long* __p = std::lower_bound(__prime_list, __prime_list
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+ _S_n_primes, __min_bkts);
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_M_next_resize =
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static_cast<std::size_t>(__builtin_ceil(*__p * _M_max_load_factor));
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return *__p;
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return _M_next_bkt(__builtin_ceil(__min_bkts));
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}
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// Finds the smallest prime p such that alpha p > __n_elt + __n_ins.
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@ -462,12 +461,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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if (__min_bkts > __n_bkt)
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{
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__min_bkts = std::max(__min_bkts, _M_growth_factor * __n_bkt);
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const unsigned long* __p =
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std::lower_bound(__prime_list, __prime_list + _S_n_primes,
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__min_bkts);
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_M_next_resize = static_cast<std::size_t>
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(__builtin_ceil(*__p * _M_max_load_factor));
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return std::make_pair(true, *__p);
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return std::make_pair(true,
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_M_next_bkt(__builtin_ceil(__min_bkts)));
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}
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else
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{
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@ -46,22 +46,38 @@ namespace __detail
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{
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// Optimize lookups involving the first elements of __prime_list.
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// (useful to speed-up, eg, constructors)
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static const unsigned char __fast_bkt[12]
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= { 2, 2, 2, 3, 5, 5, 7, 7, 11, 11, 11, 11 };
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static const unsigned char __fast_bkt[13]
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= { 2, 2, 3, 5, 5, 7, 7, 11, 11, 11, 11, 13, 13 };
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if (__n <= 11)
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if (__n <= 12)
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{
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_M_next_resize =
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__builtin_ceil(__fast_bkt[__n] * (long double)_M_max_load_factor);
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return __fast_bkt[__n];
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}
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// Number of primes (without sentinel).
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constexpr auto __n_primes
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= sizeof(__prime_list) / sizeof(unsigned long) - 1;
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// Don't include the last prime in the search, so that anything
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// higher than the second-to-last prime returns a past-the-end
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// iterator that can be dereferenced to get the last prime.
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constexpr auto __last_prime = __prime_list + __n_primes - 1;
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// Look for 'n + 1' to make sure returned value will be greater than n.
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const unsigned long* __next_bkt =
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std::lower_bound(__prime_list + 5, __prime_list + __n_primes, __n);
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_M_next_resize =
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__builtin_ceil(*__next_bkt * (long double)_M_max_load_factor);
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std::lower_bound(__prime_list + 6, __last_prime, __n + 1);
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if (__next_bkt == __last_prime)
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// Set next resize to the max value so that we never try to rehash again
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// as we already reach the biggest possible bucket number.
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// Note that it might result in max_load_factor not being respected.
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_M_next_resize = std::size_t(-1);
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else
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_M_next_resize =
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__builtin_ceil(*__next_bkt * (long double)_M_max_load_factor);
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return *__next_bkt;
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}
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@ -25,6 +25,7 @@
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namespace __detail
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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// The sentinel value is kept only for abi backward compatibility.
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extern const unsigned long __prime_list[] = // 256 + 1 or 256 + 48 + 1
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{
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2ul, 3ul, 5ul, 7ul, 11ul, 13ul, 17ul, 19ul, 23ul, 29ul, 31ul,
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@ -0,0 +1,63 @@
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// Copyright (C) 2016 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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//
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// { dg-options "-std=gnu++11" }
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#include <unordered_set>
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#include <testsuite_hooks.h>
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template<typename _USet>
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void test(int threshold)
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{
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bool test __attribute__((unused)) = true;
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_USet us;
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auto nb_reserved = us.bucket_count();
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us.reserve(nb_reserved);
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auto bkts = us.bucket_count();
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for (int i = 0; i != threshold; ++i)
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{
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if (i == nb_reserved)
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{
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nb_reserved = bkts;
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us.reserve(nb_reserved);
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bkts = us.bucket_count();
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}
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us.insert(i);
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VERIFY( us.bucket_count() == bkts );
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}
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}
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template<typename _Value>
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using unordered_set_power2_rehash =
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std::_Hashtable<_Value, _Value, std::allocator<_Value>,
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std::__detail::_Identity,
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std::equal_to<_Value>,
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std::hash<_Value>,
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std::__detail::_Mask_range_hashing,
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std::__detail::_Default_ranged_hash,
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std::__detail::_Power2_rehash_policy,
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std::__detail::_Hashtable_traits<false, true, true>>;
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int main()
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{
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test<std::unordered_set<int>>(150);
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test<unordered_set_power2_rehash<int>>(150);
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return 0;
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}
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@ -17,6 +17,7 @@
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//
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// { dg-options "-std=gnu++11" }
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#include <limits>
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#include <unordered_set>
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#include <testsuite_hooks.h>
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@ -35,8 +36,32 @@ void test01()
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== (std::size_t(1) << (sizeof(std::size_t) * 8 - 1)) );
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}
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void test02()
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{
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bool test __attribute__((unused)) = true;
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std::__detail::_Power2_rehash_policy policy;
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for (std::size_t i = 1;;)
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{
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auto nxt = policy._M_next_bkt(i);
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if (nxt == i)
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{
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// Equals only when reaching max.
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constexpr auto mx = std::numeric_limits<std::size_t>::max();
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VERIFY( nxt == policy._M_next_bkt(mx) );
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break;
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}
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VERIFY( nxt > i );
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i = nxt;
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}
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}
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int main()
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{
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test01();
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test02();
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return 0;
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}
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@ -0,0 +1,52 @@
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// Copyright (C) 2016 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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//
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// { dg-options "-std=gnu++11" }
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#include <limits>
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#include <unordered_set>
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#include <testsuite_hooks.h>
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void test01()
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{
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bool test __attribute__((unused)) = true;
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std::__detail::_Prime_rehash_policy policy;
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for (std::size_t i = 1;;)
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{
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auto nxt = policy._M_next_bkt(i);
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if (nxt == i)
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{
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// Equals only when reaching max.
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constexpr auto mx = std::numeric_limits<std::size_t>::max() - 1;
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VERIFY( nxt == policy._M_next_bkt(mx) );
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break;
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}
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VERIFY( nxt > i );
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i = nxt;
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}
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}
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int main()
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{
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test01();
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return 0;
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}
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@ -22,40 +22,40 @@
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#include <testsuite_hooks.h>
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template<typename _USet>
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void test()
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{
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bool test __attribute__((unused)) = true;
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_USet us;
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typedef typename _USet::size_type size_type;
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bool rehashed = false;
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for (int i = 0; i != 100000; ++i)
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void test()
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{
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size_type bkt_count = us.bucket_count();
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us.insert(i);
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if (bkt_count != us.bucket_count())
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bool test __attribute__((unused)) = true;
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_USet us;
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typedef typename _USet::size_type size_type;
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bool rehashed = false;
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for (int i = 0; i != 100000; ++i)
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{
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// Container has been rehashed, lets check that it won't be rehash again
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// if we remove and restore the last 2 inserted elements:
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rehashed = true;
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bkt_count = us.bucket_count();
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VERIFY( us.erase(i) == 1 );
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VERIFY( bkt_count == us.bucket_count() );
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if (i > 0)
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size_type bkt_count = us.bucket_count();
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us.insert(i);
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if (bkt_count != us.bucket_count())
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{
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VERIFY( us.erase(i - 1) == 1 );
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// Container has been rehashed, lets check that it won't be rehash
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// again if we remove and restore the last 2 inserted elements:
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rehashed = true;
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bkt_count = us.bucket_count();
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VERIFY( us.erase(i) == 1 );
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VERIFY( bkt_count == us.bucket_count() );
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if (i > 0)
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{
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VERIFY( us.erase(i - 1) == 1 );
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VERIFY( bkt_count == us.bucket_count() );
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VERIFY( us.insert(i - 1).second );
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VERIFY( us.insert(i - 1).second );
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VERIFY( bkt_count == us.bucket_count() );
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}
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VERIFY( us.insert(i).second );
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VERIFY( bkt_count == us.bucket_count() );
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}
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VERIFY( us.insert(i).second );
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VERIFY( bkt_count == us.bucket_count() );
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}
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}
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// At lest we check a rehash once:
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VERIFY( rehashed );
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}
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// At lest we check a rehash once:
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VERIFY( rehashed );
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}
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template<typename _Value>
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using unordered_set_power2_rehash =
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