2024. május 18., szombat 3:01 keltezéssel, Barnabás Pőcze
<po...@protonmail.com> írta:
> Hi
>
>
> 2024. március 13., szerda 12:43 keltezéssel, Jonathan Wakely
> <jwak...@redhat.com> írta:
>
> > On Mon, 11 Mar 2024 at 23:36, Barnabás Pőcze <po...@protonmail.com> wrote:
> > >
> > > Previously, calling erase(key) on both std::map and std::set
> > > would execute that same code that std::multi{map,set} would.
> > > However, doing that is unnecessary because std::{map,set}
> > > guarantee that all elements are unique.
> > >
> > > It is reasonable to expect that erase(key) is equivalent
> > > or better than:
> > >
> > > auto it = m.find(key);
> > > if (it != m.end())
> > > m.erase(it);
> > >
> > > However, this was not the case. Fix that by adding a new
> > > function _Rb_tree<>::_M_erase_unique() that is essentially
> > > equivalent to the above snippet, and use this from both
> > > std::map and std::set.
> >
> > Hi, this change looks reasonable, thanks for the patch. Please note
> > that GCC is currently in "stage 3" of its dev process so this change
> > would have to wait until after GCC 14 branches from trunk, due in a
> > few weeks.
>
> As far as I can see GCC 14 has been released, so I pulled and ran the test
> suite
> again:
>
> make check-target-libstdc++-v3
> RUNTESTFLAGS="conformance.exp=23_containers/*"
>
> and it reported no failures. Is there anything else I should do?
Anything else I should do here? I apologize if the window for new changes
has not opened yet, I don't know how that is done in gcc.
Regards,
Barnabás Pőcze
>
>
> Regards,
> Barnabás Pőcze
>
> >
> > I assume you ran the testsuite with no regressions. Do you have
> > benchmarks to show this making a difference?
> >
> >
> > >
> > > libstdc++-v3/ChangeLog:
> > >
> > > PR libstdc++/112934
> > > * include/bits/stl_tree.h (_Rb_tree<>::_M_erase_unique): Add.
> > > * include/bits/stl_map.h (map<>::erase): Use _M_erase_unique.
> > > * include/bits/stl_set.h (set<>::erase): Likewise.
> > > ---
> > > libstdc++-v3/include/bits/stl_map.h | 2 +-
> > > libstdc++-v3/include/bits/stl_set.h | 2 +-
> > > libstdc++-v3/include/bits/stl_tree.h | 17 +++++++++++++++++
> > > 3 files changed, 19 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/libstdc++-v3/include/bits/stl_map.h
> > > b/libstdc++-v3/include/bits/stl_map.h
> > > index ad58a631af5..229643b77fd 100644
> > > --- a/libstdc++-v3/include/bits/stl_map.h
> > > +++ b/libstdc++-v3/include/bits/stl_map.h
> > > @@ -1115,7 +1115,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
> > > */
> > > size_type
> > > erase(const key_type& __x)
> > > - { return _M_t.erase(__x); }
> > > + { return _M_t._M_erase_unique(__x); }
> > >
> > > #if __cplusplus >= 201103L
> > > // _GLIBCXX_RESOLVE_LIB_DEFECTS
> > > diff --git a/libstdc++-v3/include/bits/stl_set.h
> > > b/libstdc++-v3/include/bits/stl_set.h
> > > index c0eb4dbf65f..51a1717ec62 100644
> > > --- a/libstdc++-v3/include/bits/stl_set.h
> > > +++ b/libstdc++-v3/include/bits/stl_set.h
> > > @@ -684,7 +684,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
> > > */
> > > size_type
> > > erase(const key_type& __x)
> > > - { return _M_t.erase(__x); }
> > > + { return _M_t._M_erase_unique(__x); }
> > >
> > > #if __cplusplus >= 201103L
> > > // _GLIBCXX_RESOLVE_LIB_DEFECTS
> > > diff --git a/libstdc++-v3/include/bits/stl_tree.h
> > > b/libstdc++-v3/include/bits/stl_tree.h
> > > index 6f470f04f6a..9e80d449c7e 100644
> > > --- a/libstdc++-v3/include/bits/stl_tree.h
> > > +++ b/libstdc++-v3/include/bits/stl_tree.h
> > > @@ -1225,6 +1225,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > > size_type
> > > erase(const key_type& __x);
> > >
> > > + size_type
> > > + _M_erase_unique(const key_type& __x);
> > > +
> > > #if __cplusplus >= 201103L
> > > // _GLIBCXX_RESOLVE_LIB_DEFECTS
> > > // DR 130. Associative erase should return an iterator.
> > > @@ -2518,6 +2521,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > > return __old_size - size();
> > > }
> > >
> > > + template<typename _Key, typename _Val, typename _KeyOfValue,
> > > + typename _Compare, typename _Alloc>
> > > + typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare,
> > > _Alloc>::size_type
> > > + _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
> > > + _M_erase_unique(const _Key& __x)
> > > + {
> > > + iterator __it = find(__x);
> > > + if (__it == end())
> > > + return 0;
> > > +
> > > + _M_erase_aux(__it);
> > > + return 1;
> > > + }
> > > +
> > > template<typename _Key, typename _Val, typename _KeyOfValue,
> > > typename _Compare, typename _Alloc>
> > > typename _Rb_tree<_Key, _Val, _KeyOfValue,
> > > --
> > > 2.44.0
> > >
> > >
> >
