[PATCH] libstdc++: Skip atomic instructions in _Sp_counted_base::_M_release when both counts are 1

[Jonathan Wakely]

On Mon, 2 Aug 2021 at 14:29, Maged Michael wrote:
>
> This is the right patch. The previous one is missing noexcept. Sorry.
>
>
> On Mon, Aug 2, 2021 at 9:23 AM Maged Michael <maged.michael@gmail.com> wrote:
>>
>> Please find attached an updated patch after incorporating Jonathan's suggestions.
>>
>> Changes from the last patch include:
>> - Add a TSAN macro to bits/c++config.
>> - Use separate constexpr bool-s for the conditions for lock-freedom, double-width and alignment.
>> - Move the code in the optimized path to a separate function _M_release_double_width_cas.

Thanks for the updated patch. At a quick glance it looks great. I'll
apply it locally and test it tomorrow.