This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: [RFC] Tightening up the type system
On Tue, 2004-09-28 at 13:05, Andrew Haley wrote:
> Diego Novillo writes:
> >
> >
> > My question to the FE folks is: what are the right semantics for
> > checking MODIFY_EXPR? Is compatible_types_p too strict? Should we have
> > had a cast operation in the above assignment?
> >
> > Not having the right types is increasingly getting in the way of the
> > optimizers because we use compatible_types_p quite often to validate
> > propagation opportunities.
>
> It's an interesting view. I'm pretty sure that we violate this is the
> Java FE in a few places, but perhaps we shouldn't. The trouble is
> that the GENERIC type system has never been so well-defined.
>
We use lang_hooks for adhering to the FE type system. We don't really
have a GENERIC/GIMPLE type system.
Maybe we should if we lowered GIMPLE one more step, but for now we tie
the optimizers to the FE's type system.
> I'm sure that enforcing this would break things and it would take some
> time to find and fix them all.
>
As a stop-gap measure, we could probably ask the gimplifier to
fold_convert operands into the right type.
Diego.