On Mon, May 26, 2014 at 08:36:31AM -0700, Mike Stump wrote:
> On May 26, 2014, at 2:22 AM, FX <fxcoud...@gmail.com> wrote:
> >> This causes GCC bootstrap to fail on Darwin systems (whose system compiler
> >> is clang-based). Since PR 61146 was resolved as INVALID (but I’m not sure
> >> it’s the right call, see below), I’ve filed a separate report for the
> >> bootstrap issue (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61315).
> >
> > Since my PR has been closed twice by Andrew Pinski (“it’s clang’s fault,
> > bouh ouh”), I’d ask the maintainers to step in. Can we please provide a GCC
> > that works for the default darwin setup? Or at least drop darwin as
> > secondary target and document the failure?
>
> The best coarse of action, post a patch, have it reviewed and put in.
> Current action, a patch has been posted, the review is outstanding, I’d
> like to see it put in; though, I am curious why the casts were there in
> the first place.
Note, haven't added them there, but from what I can test, the casts there
can serve as a compile time check that the right type is used, e.g.
unsigned long i;
void
foo (void)
{
asm volatile ("# %0 %1" : "=r" ((unsigned long long) i) : "0" ((unsigned long
long) 0));
}
errors out on x86_64 -m32, but compiles fine with -m64, because in the
latter case the type has the correct size, while in the former case it
doesn't. So, perhaps instead of removing the casts we should replace them
with some kind of static assertions (whether
extern char foobar[sizeof (arg) == sizeof (UDItype) && __builtin_classify_type
(arg) == 1 ? 1 : -1];
or __builtin_types_compatible_p, or C++ templates for C++, ...
Jakub
