On Tue, 2018-11-20 at 02:46 +0000, Joseph Myers wrote:
> On Mon, 19 Nov 2018, David Malcolm wrote:
>
> > +/* C implementation of same_type_p.
> > + Returns true iff TYPE1 and TYPE2 are the same type, in the
> > usual
> > + sense of `same'. */
> > +
> > +bool
> > +same_type_p (tree type1, tree type2)
> > +{
> > + return comptypes (type1, type2) == 1;
> > +}
>
> I don't think "compatible" and "same" are the same concept. Normally
> in C
> you'd be concerned with compatibility; "same type" is only used for
> the
> rule on duplicate typedefs, which uses
> comptypes_check_different_types.
The purpose here is to be able to offer fix-it hints for bogus code
that's missing an '&' or a '*' prefix, and have that code live in c-
common.c
Jason wanted to avoid a pointer-equality test for types by using
same_type_p to look through enums - but same_type_p is C++-specific.
Should I do:
(a) something like this for C:
/* C implementation of same_type_p.
Returns true iff TYPE1 and TYPE2 are the same type, or are
compatible enough to be permitted in C11 typedef redeclarations. */
bool
same_type_p (tree type1, tree type2)
{
bool different_types_p = false;
int result = comptypes_check_different_types (type1, type2,
&different_types_p);
if (result == 1 && !different_types_p)
return true;
return false;
}
(b) provide a same_type_p for C that e.g. simply does pointer equality,
(d) add a newly named function (e.g. "compatible_types_p", as C++ has a
comptypes, but it has a 3rd param), or
(d) fall back to simply doing pointer equality.
Thanks
Dave
