Re: [PATCH] typeof: Remove type qualifiers for atomic types

[Sebastian Huber <sebastian dot huber at embedded-brains dot de>]

On 06/25/2014 05:56 PM, Joseph S. Myers wrote:
> On Wed, 25 Jun 2014, Sebastian Huber wrote:
>
> > 2014-06-25  Sebastian Huber  <sebastian.huber@embedded-brains.de>
> >
> > 	* c-parser.c (c_parser_declaration_or_fndef): Discard all type
> > 	qualifiers in __auto_type for atomic types.
> > 	(c_parser_typeof_specifier): Discard all type qualifiers in
> > 	__typeof__ for atomic types.
> This patch should include a testcase that typeof is discarding volatile
> (you can e.g. declare an extern variable twice, once as int and once as
> typeof (*p) where p is volatile _Atomic int *, so the type compatibility
> check fails unless volatile is discarded).

Would be something like this all right for the check?

#define CHECK_CORRESPONDING(TYPE1, TYPE2) \
do { TYPE1 a; TYPE2 *b = &a; TYPE2 c; TYPE1 *d = &c; } while (0)

void f(void)
{
const int *ci;
volatile int *vi;
CHECK_CORRESPONDING(int *, __typeof__(ci));
CHECK_CORRESPONDING(int *, __typeof__(vi));
}

It generates warnings:

test.c: In function ‘f’:
test.c:8:2: warning: initialization from incompatible pointer type 
[enabled by default]
test.c:8:2: warning: initialization from incompatible pointer type 
[enabled by default]
test.c:9:2: warning: initialization from incompatible pointer type 
[enabled by default]
test.c:9:2: warning: initialization from incompatible pointer type 
[enabled by default]

It is similar to:

gcc/testsuite/gcc.dg/c99-stdint-3.c

I think its not possible to write a test for the restrict, since it 
cannot be part of a type?

--
Sebastian Huber, embedded brains GmbH

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