> On 14 Jan 2026, at 18:45, Alejandro Colomar <une+cxx_std-proposals_at_[hidden]> wrote:
>
> Hi Hans,
>
> On Wed, Jan 14, 2026 at 06:31:06PM +0100, Hans Åberg wrote:
>>>>> What Hans has to show and has so far failed to do is that it would be
>>>>> *impossible* for LLVM to match the performance of his code, providing a reason
>>>>> why that would be the case.
>>>>
>>>> It looks difficult to do in C in the absence of templates, unlike C++
>>>> then, because the code should be expanded statically for pipelining,
>>>> even though there are suggestions in this thread that it might be possible.
>>>
>>> LLVM should be able to implement _BinInt() as a template if it would
>>> make it more efficient. That's an implementation detail. The fact that
>>> it's *currently* written in C doesn't prevent them from rewriting it in
>>> C++, or in assembly.
>>
>> Indeed, it is a C compatibility type, intended to work exactly in C,
>> which imposes some limitations. Discussions in the past focused on
>> making a separate C++ type for bit interesting, which I think would be
>> good.
>
> Compatibility with C is not a problem.
>
> - strchr(3) is a C function, and C++ implements it with an overload.
>
> - countof() is an operator for C arrays, and gnulib implements it with
> templates for C++.
> <https://gitweb.git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/stdcountof.in.h;h=cf3fc1e560e900a23a2fc1123f2c2ca5016300b3;hb=HEAD>

Then it should work if it is allowed to pad to 2⁽2^k) words.