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functional_hash.h (std::__is_fast_hash<>): New.

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2013-02-04  François Dumont  <fdumont@gcc.gnu.org>

	* include/bits/functional_hash.h (std::__is_fast_hash<>): New.
	* include/bits/basic_string.h: Specialize previous to mark
	std::hash for string types as slow.
	* include/bits/hashtable.h (__cache_default): Replace is_integral
	with __is_fast_hash.
	* src/c++11/hash_c++0x.cc: Add type_traits include.
	* testsuite/23_containers/unordered_set/instantiation_neg.cc:
	Adapt dg-error line number.
	* testsuite/23_containers/unordered_set/
	not_default_constructible_hash_neg.cc: Likewise.

From-SVN: r195738
This commit is contained in:
François Dumont 2013-02-04 21:14:07 +00:00
parent f3bd007a3a
commit 4df047dd34
7 changed files with 46 additions and 5 deletions
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13
libstdc++-v3/ChangeLog
View File

@ -1,3 +1,16 @@
2013-02-04 François Dumont <fdumont@gcc.gnu.org>
* include/bits/functional_hash.h (std::__is_fast_hash<>): New.
* include/bits/basic_string.h: Specialize previous to mark
std::hash for string types as slow.
* include/bits/hashtable.h (__cache_default): Replace is_integral
with __is_fast_hash.
* src/c++11/hash_c++0x.cc: Add type_traits include.
* testsuite/23_containers/unordered_set/instantiation_neg.cc:
Adapt dg-error line number.
* testsuite/23_containers/unordered_set/
not_default_constructible_hash_neg.cc: Likewise.
2013-02-04 Manuel López-Ibáñez <manu@gcc.gnu.org>
Paolo Carlini <paolo.carlini@oracle.com>

16
libstdc++-v3/include/bits/basic_string.h
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@ -3051,6 +3051,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return std::_Hash_impl::hash(__s.data(), __s.length()); }
};
template<>
struct __is_fast_hash<hash<string>> : std::false_type
{ };
#ifdef _GLIBCXX_USE_WCHAR_T
/// std::hash specialization for wstring.
template<>
@ -3062,6 +3066,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return std::_Hash_impl::hash(__s.data(),
__s.length() * sizeof(wchar_t)); }
};
template<>
struct __is_fast_hash<hash<wstring>> : std::false_type
{ };
#endif
#endif /* _GLIBCXX_COMPATIBILITY_CXX0X */
@ -3077,6 +3085,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__s.length() * sizeof(char16_t)); }
};
template<>
struct __is_fast_hash<hash<u16string>> : std::false_type
{ };
/// std::hash specialization for u32string.
template<>
struct hash<u32string>
@ -3087,6 +3099,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return std::_Hash_impl::hash(__s.data(),
__s.length() * sizeof(char32_t)); }
};
template<>
struct __is_fast_hash<hash<u32string>> : std::false_type
{ };
#endif
_GLIBCXX_END_NAMESPACE_VERSION

12
libstdc++-v3/include/bits/functional_hash.h
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@ -194,6 +194,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// @} group hashes
// Hint about performance of hash functor. If not fast the hash based
// containers will cache the hash code.
// Default behavior is to consider that hasher are fast unless specified
// otherwise.
template<typename _Hash>
struct __is_fast_hash : public std::true_type
{ };
template<>
struct __is_fast_hash<hash<long double>> : public std::false_type
{ };
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

5
libstdc++-v3/include/bits/hashtable.h
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@ -40,9 +40,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Tp, typename _Hash>
using __cache_default
= __not_<__and_<// Do not cache for builtin integral types having trivial
// hasher.
is_integral<_Tp>,
= __not_<__and_<// Do not cache for fast hasher.
__is_fast_hash<_Hash>,
// Mandatory to make local_iterator default
// constructible.
is_default_constructible<_Hash>,

1
libstdc++-v3/src/c++11/hash_c++0x.cc
View File

@ -26,6 +26,7 @@
# error "hash_c++0x.cc must be compiled with -std=gnu++0x"
#endif
#include <type_traits>
#include <bits/functional_hash.h>
namespace std _GLIBCXX_VISIBILITY(default)

2
libstdc++-v3/testsuite/23_containers/unordered_set/instantiation_neg.cc
View File

@ -19,7 +19,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-error "with noexcept" "" { target *-*-* } 252 }
// { dg-error "with noexcept" "" { target *-*-* } 251 }
#include <unordered_set>

2
libstdc++-v3/testsuite/23_containers/unordered_set/not_default_constructible_hash_neg.cc
View File

@ -19,7 +19,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-error "default constructible" "" { target *-*-* } 268 }
// { dg-error "default constructible" "" { target *-*-* } 267 }
#include <unordered_set>