Re: _LIBCXX_DEBUG value initialized singular iterators assert failures in std algorithms [PR104316]

["François Dumont" <frs.dumont@gmail.com>]

Both committed now.

Just to confirm, those 2 last patches should be backported to gcc-13 
branch, right ?

I might have a try to update version.h but if you want to do it before 
don't hesitate.

François

On 18/03/2024 08:45, Jonathan Wakely wrote:
> On Sun, 17 Mar 2024 at 18:14, François Dumont <frs.dumont@gmail.com> wrote:
>> I was a little bit too confident below. After review of all _M_singular
>> usages I found another necessary fix.
>>
>> After this one for sure we will be able to define
>> __cpp_lib_null_iterators even in Debug mode.
>>
>>       libstdc++: Fix N3344 behavior on _Safe_iterator::_M_can_advance
>>
>>       We shall be able to advance from a 0 offset a value-initialized
>> iterator.
>>
>>       libstdc++-v3/ChangeLog:
>>
>>               * include/debug/safe_iterator.tcc
>> (_Safe_iterator<>::_M_can_advance):
>>               Accept 0 offset advance on value-initialized iterator.
>>               * testsuite/23_containers/vector/debug/n3644.cc: New test case.
>>
>> Ok to commit ?
>
> OK, thanks.
>
>
>> François
>>
>>
>> On 17/03/2024 17:52, François Dumont wrote:
>>>> OK for trunk, thanks!
>>>>
>>>> I think this is OK to backport to 13 too.
>>>>
>>>> Maybe after this we can define the __cpp_lib_null_itetators macro for
>>>> debug mode?
>>>>
>>> After this fix of local_iterator I think we can indeed.
>>>
>>> In fact the added 11316.cc was already passing for
>>> unordered_set<>::local_iterator but simply because we were missing the
>>> singular check. Both issues solved with this patch.
>>>
>>> I found the version.def file to cleanup but no idea how to regenerate
>>> version.h from it so I'll let you do it, ok ?
>>>
>>>      libstdc++: Fix _Safe_local_iterator<>::_M_valid_range
>>>
>>>      Unordered container local_iterator range shall not contain any
>>> singular
>>>      iterator unless both iterators are value-initialized.
>>>
>>>      libstdc++-v3/ChangeLog:
>>>
>>>              * include/debug/safe_local_iterator.tcc
>>>              (_Safe_local_iterator::_M_valid_range): Add
>>> _M_value_initialized and
>>>              _M_singular checks.
>>>              * testsuite/23_containers/unordered_set/debug/114316.cc:
>>> New test case.
>>>
>>>
>>> Ok to commit ?
>>>
>>> François