[patch] C++14: N3671 Making non-modifying sequence operations more robust
Jonathan Wakely
jwakely.gcc@gmail.com
Mon Jun 17 00:48:00 GMT 2013
On 15 June 2013 16:48, Jonathan Wakely wrote:
> On 11 June 2013 00:11, Jonathan Wakely wrote:
>> On 10 June 2013 23:08, Chris Jefferson wrote:
>>> After we are in the 'if(__ra_iters)' case, and checked that __d1==__d2,
>>> could dispatch to old-fashioned equal(__first1, __last1, __first2,
>>> __binary_pred). This has the advantage that it saves repeatedly checking
>>> __first2 != __last2 unnessasairly, and I suspect only having one loop
>>> condition to check will give the compiler a better shot at optimising /
>>> unrolling (although, I haven't checked that I will admit).
>>
>> Good idea, thanks, I'll make that change too.
>
> How's this? I made both the new std::equal() overloads defer to the
> old ones when both sets of iterators are random access. That means
> there's no need for the __equal2 class template, the memcmp special
> case for pointers is handled by the old std::equal().
I'm committing the attached, which also fixes some silly typos in the
new is_permutation overloads.
Tested x86_64-linux.
2013-06-17 Jonathan Wakely <jwakely.gcc@gmail.com>
Chris Jefferson <chris@bubblescope.net>
* include/bits/stl_algobase.h (equal): Make C++14 overloads from N3671
dispatch to traditional std::equal for random-access iterators.
(__equal2_aux, __equal2): Remove.
(__equal::equal): Remove unused overloads.
* include/bits/stl_algo.h (is_permutation): Fix typos.
-------------- next part --------------
commit 0bf845495124778bad276447cd2ce12cb888f921
Author: Jonathan Wakely <jwakely.gcc@gmail.com>
Date: Mon Jun 17 01:30:37 2013 +0100
2013-06-17 Jonathan Wakely <jwakely.gcc@gmail.com>
Chris Jefferson <chris@bubblescope.net>
* include/bits/stl_algobase.h (equal): Make C++14 overloads from N3671
dispatch to traditional std::equal for random-access iterators.
(__equal2_aux, __equal2): Remove.
(__equal::equal): Remove unused overloads.
* include/bits/stl_algo.h (is_permutation): Fix typos.
diff --git a/libstdc++-v3/include/bits/stl_algo.h b/libstdc++-v3/include/bits/stl_algo.h
index e61f22b..9d6b466 100644
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -4396,7 +4396,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
= typename iterator_traits<_ForwardIterator2>::iterator_category;
using _It1_is_RA = is_same<_Cat1, random_access_iterator_tag>;
using _It2_is_RA = is_same<_Cat2, random_access_iterator_tag>;
- if (_It1_is_RA() && _It1_is_RA())
+ if (_It1_is_RA() && _It2_is_RA())
{
auto __d1 = std::distance(__first1, __last1);
auto __d2 = std::distance(__first2, __last2);
@@ -4456,7 +4456,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
= typename iterator_traits<_ForwardIterator2>::iterator_category;
using _It1_is_RA = is_same<_Cat1, random_access_iterator_tag>;
using _It2_is_RA = is_same<_Cat2, random_access_iterator_tag>;
- constexpr bool __ra_iters = _It1_is_RA() && _It1_is_RA();
+ constexpr bool __ra_iters = _It1_is_RA() && _It2_is_RA();
if (__ra_iters)
{
auto __d1 = std::distance(__first1, __last1);
diff --git a/libstdc++-v3/include/bits/stl_algobase.h b/libstdc++-v3/include/bits/stl_algobase.h
index 67f859b..e1daac2 100644
--- a/libstdc++-v3/include/bits/stl_algobase.h
+++ b/libstdc++-v3/include/bits/stl_algobase.h
@@ -798,19 +798,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return false;
return true;
}
-
-#if __cplusplus > 201103L
- template<typename _II1, typename _II2>
- static bool
- equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
- {
- for (; __first1 != __last1 && __first2 != __last2;
- ++__first1, ++__first2)
- if (!(*__first1 == *__first2))
- return false;
- return true;
- }
-#endif
};
template<>
@@ -823,17 +810,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
* (__last1 - __first1));
}
-
-#if __cplusplus > 201103L
- template<typename _Tp>
- static bool
- equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2,
- const _Tp* __last2)
- {
- return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
- * (__last1 - __first1));
- }
-#endif
};
template<typename _II1, typename _II2>
@@ -851,66 +827,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return std::__equal<__simple>::equal(__first1, __last1, __first2);
}
-#if __cplusplus > 201103L
- template<bool _BoolType>
- struct __equal2
- {
- template<typename _It>
- using _IterCat = typename iterator_traits<_It>::iterator_category;
- template<typename _It>
- using _IsRA = is_same<_IterCat<_It>, random_access_iterator_tag>;
-
- template<typename _II1, typename _II2>
- static bool
- equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
- {
- constexpr bool __ra_iters = _IsRA<_II1>() && _IsRA<_II2>();
- if (__ra_iters)
- {
- auto __d1 = std::distance(__first1, __last1);
- auto __d2 = std::distance(__first2, __last2);
- if (__d1 != __d2)
- return false;
- }
- for (; __first1 != __last1 && __first2 != __last2;
- ++__first1, ++__first2)
- if (!(*__first1 == *__first2))
- return false;
- return __ra_iters || (__first1 == __last1 && __first2 == __last2);
- }
- };
-
- template<>
- struct __equal2<true>
- {
- template<typename _Tp>
- static bool
- equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2,
- const _Tp* __last2)
- {
- if ((__last1 - __first1) != (__last2 - __first2))
- return false;
- return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
- * (__last1 - __first1));
- }
- };
-
- template<typename _II1, typename _II2>
- inline bool
- __equal2_aux(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
- {
- typedef typename iterator_traits<_II1>::value_type _ValueType1;
- typedef typename iterator_traits<_II2>::value_type _ValueType2;
- const bool __simple = ((__is_integer<_ValueType1>::__value
- || __is_pointer<_ValueType1>::__value)
- && __is_pointer<_II1>::__value
- && __is_pointer<_II2>::__value
- && __are_same<_ValueType1, _ValueType2>::__value);
-
- return __equal2<__simple>::equal(__first1, __last1, __first2, __last2);
- }
-#endif
-
template<typename, typename>
struct __lc_rai
{
@@ -1174,10 +1090,23 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
- return std::__equal2_aux(std::__niter_base(__first1),
- std::__niter_base(__last1),
- std::__niter_base(__first2),
- std::__niter_base(__last2));
+ using _RATag = random_access_iterator_tag;
+ using _Cat1 = typename iterator_traits<_II1>::iterator_category;
+ using _Cat2 = typename iterator_traits<_II2>::iterator_category;
+ using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
+ if (_RAIters())
+ {
+ auto __d1 = std::distance(__first1, __last1);
+ auto __d2 = std::distance(__first2, __last2);
+ if (__d1 != __d2)
+ return false;
+ return std::equal(__first1, __last1, __first2);
+ }
+
+ for (; __first1 != __last1 && __first2 != __last2; ++__first1, ++__first2)
+ if (!(*__first1 == *__first2))
+ return false;
+ return __first1 == __last1 && __first2 == __last2;
}
/**
@@ -1207,23 +1136,23 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
+ using _RATag = random_access_iterator_tag;
using _Cat1 = typename iterator_traits<_IIter1>::iterator_category;
using _Cat2 = typename iterator_traits<_IIter2>::iterator_category;
- using _IIter1_is_RA = is_same<_Cat1, random_access_iterator_tag>;
- using _IIter2_is_RA = is_same<_Cat2, random_access_iterator_tag>;
- constexpr bool __ra_iters = _IIter1_is_RA() && _IIter1_is_RA();
- if (__ra_iters)
+ using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
+ if (_RAIters())
{
auto __d1 = std::distance(__first1, __last1);
auto __d2 = std::distance(__first2, __last2);
if (__d1 != __d2)
return false;
+ return std::equal(__first1, __last1, __first2, __binary_pred);
}
for (; __first1 != __last1 && __first2 != __last2; ++__first1, ++__first2)
if (!bool(__binary_pred(*__first1, *__first2)))
return false;
- return __ra_iters || (__first1 == __last1 && __first2 == __last2);
+ return __first1 == __last1 && __first2 == __last2;
}
#endif
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