Re: PATCH to shorten_compare -Wtype-limits handling

[Jeff Law <law at redhat dot com>]

On 11/18/2015 09:33 PM, David Edelsohn wrote:
> On Wed, Nov 18, 2015 at 11:26 PM, Jason Merrill <jason@redhat.com> wrote:
> > The rs6000 target was hitting a bootstrap failure due to
> > -Werror=type-limits.  Since warn_tautological_cmp and other warnings avoid
> > warning if one of the operands comes from a macro, I thought it would make
> > sense to do that here as well.
> >
> > Tested that this allows rs6000 bootstrap to proceed, regression tested on
> > x86_64-pc-linux-gnu, applying to trunk.  David, do you want to revert the
> > #pragma GCC diagnostic change?
>
> Thanks for the patch.
>
> Yes, I will revert the #pragma GCC diagnostic patch.  It was meant as
> a temporary hack to fix bootstrap while a long-term solution was
> developed.
The even longer term direction for this code is to separate out the 
type-limits warning from the canonicalization and shortening.  I've got 
a blob of code form Kai that goes in that direction, but it needs more 
engineering around it.

Ideally the canonicalization/shortening moves into match.pd.  The 
warning, in theory, moves out of the front-ends as well.



jeff