[PATCH] Add optional __Bfloat16 support

[H.J. Lu]

On Fri, Jun 10, 2022 at 7:44 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, Jun 10, 2022 at 2:38 AM Florian Weimer <fweimer@redhat.com> wrote:
> >
> > * liuhongt via Libc-alpha:
> >
> > > +\subsubsection{Special Types}
> > > +
> > > +The \code{__Bfloat16} type uses a 8-bit exponent and 7-bit mantissa.
> > > +It is used for \code{BF16} related intrinsics, it cannot be
>
> Please mention that this is an alternate encoding format for 16-bit floating
> point.  It has the same size and alignment as _Float16.

It also follows the same rules as _Float16 for parameter passing and function
return.

> > > +used with standard C operators.
> >
> > I think it's not necessary to specify whether the type supports certain
> > C operators (surely assignment will work?).  If they are added later,
> > the ABI won't need changing.
> >
>
> If _Bfloat16 becomes a fundamental type, the ABI should be changed to
> move it together with other scalar types.
>
> --
> H.J.



-- 
H.J.