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* [Bug libstdc++/107367] New: All standard library algorithms should detect whether they are contiguous iterators after C++20 @ 2022-10-24 2:28 unlvsur at live dot com 2022-10-24 2:33 ` [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when " unlvsur at live dot com ` (4 more replies) 0 siblings, 5 replies; 6+ messages in thread From: unlvsur at live dot com @ 2022-10-24 2:28 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107367 Bug ID: 107367 Summary: All standard library algorithms should detect whether they are contiguous iterators after C++20 Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: unlvsur at live dot com Target Milestone: --- https://github.com/gcc-mirror/gcc/blob/00716b776200c2de6813ce706d2757eec4cb2735/libstdc%2B%2B-v3/include/bits/stl_algo.h#L3229 Take is_sorted for example: template<typename _ForwardIterator> _GLIBCXX20_CONSTEXPR inline bool is_sorted(_ForwardIterator __first, _ForwardIterator __last) { return std::is_sorted_until(__first, __last) == __last; } It should be optimized to template<typename _ForwardIterator> _GLIBCXX20_CONSTEXPR inline bool is_sorted(_ForwardIterator __first, _ForwardIterator __last) { if constexpr(contiguous_iterator<_ForwardIterator>&&!is_pointer_v<_ForwardIterator>) { return is_sorted(to_address(__first),to_address(__last)); } else { return std::is_sorted_until(__first, __last) == __last; } } ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when they are contiguous iterators after C++20 2022-10-24 2:28 [Bug libstdc++/107367] New: All standard library algorithms should detect whether they are contiguous iterators after C++20 unlvsur at live dot com @ 2022-10-24 2:33 ` unlvsur at live dot com 2022-10-25 3:36 ` unlvsur at live dot com ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: unlvsur at live dot com @ 2022-10-24 2:33 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107367 --- Comment #1 from cqwrteur <unlvsur at live dot com> --- This optimization will prevent duplications of templates over iterators and pointers. (vector<int>::iterator and int* duplications for example) For example: https://godbolt.org/z/9zEajxxa8 vs https://godbolt.org/z/n61vEddj1 579 vs 879 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when they are contiguous iterators after C++20 2022-10-24 2:28 [Bug libstdc++/107367] New: All standard library algorithms should detect whether they are contiguous iterators after C++20 unlvsur at live dot com 2022-10-24 2:33 ` [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when " unlvsur at live dot com @ 2022-10-25 3:36 ` unlvsur at live dot com 2023-12-16 18:40 ` unlvsur at live dot com ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: unlvsur at live dot com @ 2022-10-25 3:36 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107367 --- Comment #2 from cqwrteur <unlvsur at live dot com> --- (In reply to cqwrteur from comment #1) > This optimization will prevent duplications of templates over iterators and > pointers. (vector<int>::iterator and int* duplications for example) > > For example: > > https://godbolt.org/z/9zEajxxa8 > vs > https://godbolt.org/z/n61vEddj1 > > 579 vs 879 For debugging. You can do something like this template<typename ForwardIterator> concept can_optimize_to_pointer_impl = #ifdef _GLIBCXX_DEBUG false; #else std::contiguous_iterator<ForwardIterator>&&!std::is_pointer_v<ForwardIterator>; #endif template<typename ForwardIterator> constexpr void my_sort(ForwardIterator first,ForwardIterator last) { if constexpr(can_optimize_to_pointer_impl<ForwardIterator>) { std::sort(std::to_address(first),std::to_address(last)); } else { std::sort(first,last); } } https://godbolt.org/z/jj38MoWen ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when they are contiguous iterators after C++20 2022-10-24 2:28 [Bug libstdc++/107367] New: All standard library algorithms should detect whether they are contiguous iterators after C++20 unlvsur at live dot com 2022-10-24 2:33 ` [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when " unlvsur at live dot com 2022-10-25 3:36 ` unlvsur at live dot com @ 2023-12-16 18:40 ` unlvsur at live dot com 2023-12-17 13:44 ` redi at gcc dot gnu.org 2023-12-17 13:45 ` redi at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: unlvsur at live dot com @ 2023-12-16 18:40 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107367 cqwrteur <unlvsur at live dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |MOVED Status|UNCONFIRMED |RESOLVED --- Comment #3 from cqwrteur <unlvsur at live dot com> --- moved and restart ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when they are contiguous iterators after C++20 2022-10-24 2:28 [Bug libstdc++/107367] New: All standard library algorithms should detect whether they are contiguous iterators after C++20 unlvsur at live dot com ` (2 preceding siblings ...) 2023-12-16 18:40 ` unlvsur at live dot com @ 2023-12-17 13:44 ` redi at gcc dot gnu.org 2023-12-17 13:45 ` redi at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: redi at gcc dot gnu.org @ 2023-12-17 13:44 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107367 --- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- *** Bug 113046 has been marked as a duplicate of this bug. *** ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when they are contiguous iterators after C++20 2022-10-24 2:28 [Bug libstdc++/107367] New: All standard library algorithms should detect whether they are contiguous iterators after C++20 unlvsur at live dot com ` (3 preceding siblings ...) 2023-12-17 13:44 ` redi at gcc dot gnu.org @ 2023-12-17 13:45 ` redi at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: redi at gcc dot gnu.org @ 2023-12-17 13:45 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107367 Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2023-12-17 Ever confirmed|0 |1 Keywords| |missed-optimization Resolution|MOVED |--- Status|RESOLVED |NEW Severity|normal |enhancement ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-12-17 13:45 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-10-24 2:28 [Bug libstdc++/107367] New: All standard library algorithms should detect whether they are contiguous iterators after C++20 unlvsur at live dot com 2022-10-24 2:33 ` [Bug libstdc++/107367] All standard library algorithms should optimize to pointers internally when " unlvsur at live dot com 2022-10-25 3:36 ` unlvsur at live dot com 2023-12-16 18:40 ` unlvsur at live dot com 2023-12-17 13:44 ` redi at gcc dot gnu.org 2023-12-17 13:45 ` redi at gcc dot gnu.org
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