diff options
| author | Marc Glisse <marc.glisse@inria.fr> | 2018-07-26 12:01:14 +0000 |
|---|---|---|
| committer | Marc Glisse <marc.glisse@inria.fr> | 2018-07-26 12:01:14 +0000 |
| commit | c63ffd8cac7ad717ab84254a1faa418ddcb95ea1 (patch) | |
| tree | d4eca073a640be7741bd0f6c125e5ff0df6da5ec | |
| parent | a36303ddba36adbee42b524f8f4ab4fb4f9c84ad (diff) | |
optimize std::vector move assignment
2018-07-26 Marc Glisse <marc.glisse@inria.fr>
* include/bits/stl_vector.h (_Vector_impl_data::_M_copy_data): New.
(_Vector_impl_data::_M_swap_data): Use _M_copy_data.
(vector::_M_move_assign): Reorder the swaps.
git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@262998 138bc75d-0d04-0410-961f-82ee72b054a4
| -rw-r--r-- | libstdc++-v3/ChangeLog | 6 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/stl_vector.h | 19 |
2 files changed, 21 insertions, 4 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 050b027fbe5..9704fd60149 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,9 @@ +2018-07-26 Marc Glisse <marc.glisse@inria.fr> + + * include/bits/stl_vector.h (_Vector_impl_data::_M_copy_data): New. + (_Vector_impl_data::_M_swap_data): Use _M_copy_data. + (vector::_M_move_assign): Reorder the swaps. + 2018-07-26 Jonathan Wakely <jwakely@redhat.com> PR libstdc++/86676 diff --git a/libstdc++-v3/include/bits/stl_vector.h b/libstdc++-v3/include/bits/stl_vector.h index d2be98883b3..424971a02f2 100644 --- a/libstdc++-v3/include/bits/stl_vector.h +++ b/libstdc++-v3/include/bits/stl_vector.h @@ -103,11 +103,22 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER #endif void + _M_copy_data(_Vector_impl_data const& __x) _GLIBCXX_NOEXCEPT + { + _M_start = __x._M_start; + _M_finish = __x._M_finish; + _M_end_of_storage = __x._M_end_of_storage; + } + + void _M_swap_data(_Vector_impl_data& __x) _GLIBCXX_NOEXCEPT { - std::swap(_M_start, __x._M_start); - std::swap(_M_finish, __x._M_finish); - std::swap(_M_end_of_storage, __x._M_end_of_storage); + // Do not use std::swap(_M_start, __x._M_start), etc as it loses + // information used by TBAA. + _Vector_impl_data __tmp; + __tmp._M_copy_data(*this); + _M_copy_data(__x); + __x._M_copy_data(__tmp); } }; @@ -1731,8 +1742,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER _M_move_assign(vector&& __x, true_type) noexcept { vector __tmp(get_allocator()); - this->_M_impl._M_swap_data(__tmp._M_impl); this->_M_impl._M_swap_data(__x._M_impl); + __tmp._M_impl._M_swap_data(__x._M_impl); std::__alloc_on_move(_M_get_Tp_allocator(), __x._M_get_Tp_allocator()); } |