This is the mail archive of the
libstdc++@gcc.gnu.org
mailing list for the libstdc++ project.
[v3] libstdc++/41351
- From: Paolo Carlini <paolo dot carlini at oracle dot com>
- To: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Cc: libstdc++ <libstdc++ at gcc dot gnu dot org>
- Date: Tue, 03 Nov 2009 19:17:57 +0100
- Subject: [v3] libstdc++/41351
Hi,
tested x86_64-linux, committed to mainline.
Paolo.
//////////////////
2009-11-03 David Krauss <potswa@mac.com>
Paolo Carlini <paolo.carlini@oracle.com>
PR libstdc++/41351
* include/bits/stl_algo.h (__rotate(_RandomAccessIterator,
_RandomAccessIterator, _RandomAccessIterator,
random_access_iterator_tag)): Rewrite to use only std::swap in
general and std::copy/std::copy_backward when safe.
Index: include/bits/stl_algo.h
===================================================================
--- include/bits/stl_algo.h (revision 153856)
+++ include/bits/stl_algo.h (working copy)
@@ -1647,53 +1647,64 @@
typedef typename iterator_traits<_RandomAccessIterator>::value_type
_ValueType;
- const _Distance __n = __last - __first;
- const _Distance __k = __middle - __first;
- const _Distance __l = __n - __k;
+ _Distance __n = __last - __first;
+ _Distance __k = __middle - __first;
- if (__k == __l)
+ if (__k == __n - __k)
{
std::swap_ranges(__first, __middle, __middle);
return;
}
- const _Distance __d = std::__gcd(__n, __k);
+ _RandomAccessIterator __p = __first;
- for (_Distance __i = 0; __i < __d; __i++)
+ for (;;)
{
- _ValueType __tmp = _GLIBCXX_MOVE(*__first);
- _RandomAccessIterator __p = __first;
-
- if (__k < __l)
+ if (__k < __n - __k)
{
- for (_Distance __j = 0; __j < __l / __d; __j++)
+ if (__is_pod(_ValueType) && __k == 1)
{
- if (__p > __first + __l)
- {
- *__p = _GLIBCXX_MOVE(*(__p - __l));
- __p -= __l;
- }
-
- *__p = _GLIBCXX_MOVE(*(__p + __k));
- __p += __k;
+ _ValueType __t = _GLIBCXX_MOVE(*__p);
+ _GLIBCXX_MOVE3(__p + 1, __p + __n, __p);
+ *(__p + __n - 1) = _GLIBCXX_MOVE(__t);
+ return;
}
+ _RandomAccessIterator __q = __p + __k;
+ for (_Distance __i = 0; __i < __n - __k; ++ __i)
+ {
+ std::iter_swap(__p, __q);
+ ++__p;
+ ++__q;
+ }
+ __n %= __k;
+ if (__n == 0)
+ return;
+ std::swap(__n, __k);
+ __k = __n - __k;
}
else
{
- for (_Distance __j = 0; __j < __k / __d - 1; __j ++)
+ __k = __n - __k;
+ if (__is_pod(_ValueType) && __k == 1)
{
- if (__p < __last - __k)
- {
- *__p = _GLIBCXX_MOVE(*(__p + __k));
- __p += __k;
- }
- *__p = _GLIBCXX_MOVE(*(__p - __l));
- __p -= __l;
+ _ValueType __t = _GLIBCXX_MOVE(*(__p + __n - 1));
+ _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n);
+ *__p = _GLIBCXX_MOVE(__t);
+ return;
}
+ _RandomAccessIterator __q = __p + __n;
+ __p = __q - __k;
+ for (_Distance __i = 0; __i < __n - __k; ++ __i)
+ {
+ --__p;
+ --__q;
+ std::iter_swap(__p, __q);
+ }
+ __n %= __k;
+ if (__n == 0)
+ return;
+ std::swap(__n, __k);
}
-
- *__p = _GLIBCXX_MOVE(__tmp);
- ++__first;
}
}