[cfe-dev] Bitwidth attribute

[İsmail Dönmez]

Hi;

On Fri, Jan 14, 2011 at 5:49 PM, Douglas Gregor <dgregor at apple.com> wrote:

>
> On Jan 12, 2011, at 3:13 AM, ihusar wrote:
>
> > Hello,
> >
> >   I would like to ask, whether there are any plan to support the bitwidth
> attribute.
> >
> > In llvm-test-2.8 in SingleSource/UnitTests/Integer/bits.h, there is the
> attribute used:
> >
> > typedef unsigned int __attribute__((bitwidth(1))) uint1;
> > ...
> >
> > However, when I try to compile it with clang 2.8, I get this message:
> >
> > test.c:2:37: warning: unknown attribute 'bitwidth' ignored
> [-Wunknown-attributes]
> >
> >
> >   I did not try the latest llvm-gcc, but last time i tried, it did not
> work either.
> > So, I would like to ask, whether you plan to include support for the
> bitwidth attribute in the close future, or if
> > you would be willing to accept a patch that implements this support.
> >
> >   We need this to describe hardware using C and I think that we are not
> the only ones that
> > would find this useful.
>
>
> Where does this attribute come from? I don't see it in GCC's list of
> attributes, nor do I recall seeing it in other compilers.
>
> We try to add attributes when we need to for compatibility or when there's
> a strong benefit and a solid implementation for that attribute.
>

This is already reported & rejected, see
http://llvm.org/bugs/show_bug.cgi?id=1284

Regards,
ismail
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20110114/7eff4e1f/attachment.html>