Am Montag, den 23.11.2020, 20:21 +0000 schrieb Joseph Myers:
> On Mon, 23 Nov 2020, Uecker, Martin wrote:
>
> > Joseph,
> >
> > here is the patch to not drop qualifiers for _Atomic in
> > typeof. I am not sure whether this is appropriate in
> > stage3, but I wanted to leave it here for you to comment
> > and so that it does not lost.
> >
> > First, I noticed that the change to drop qualifiers
> > in lvalue conversion also implies that __auto_type now
> > always uses the non-qualified type. I think this is more
> > correct, and also what other compilers and C++'s auto do.
> > The first change here in c-parser would remove the now
> > redundant code to drop qualifiers for _Atomic types.
> >
> > The second change would remove the code to drop qualifiers
> > for _Atomic types for typeof. I would then use the
> > comma operator for stdatomic to remove all qualifiers.
> > Here, the question is whether this may have same
> > unintended side effects.
>
> This is OK, with references to bugs 65455 and 92935 as I think it fixes
> those.
>
> Any change to qualifiers for typeof risks breaking something relying on
> the details of when the result is or is not qualified, but given that in
> previous GCC versions that was poorly defined and inconsistent, making
> these changes to make it more consistent seems reasonable.
>
> It is probably still the case that _Typeof as proposed for ISO C would
> need special handling of function and function pointer types for the same
> reason as _Generic has such handling (_Noreturn not being part of the
> function type as defined by ISO C).
So OK to apply with the following Changelog?
C: Do not drop qualifiers in typeof for _Atomic types. [PR65455,PR92935]
2020-11-25 Martin Uecker <muec...@gwdg.de>
gcc/c/
* c-parsers.c (c_parser_declaration_or_fndef): Remove redundant code
to drop qualifiers of _Atomic types for __auto_type.
(c_parser_typeof_specifier): Do not drop qualifiers of _Atomic
types for __typeof__.
gcc/ginclude/
* ginclude/stdatomic.h: Use comma operator to drop qualifiers.
gcc/testsuite/
* gcc.dg/typeof-2.c: Adapt test.
