Thank you both for your quick replies.
@Joseph, thank you for linking me to the other issue. If I understand
correctly what the point is, would you then agree that the program main
when calling foo2 has *defined* behavior?
What surprises me is that *p and *q might be the same restricted pointer:
the *xp* object itself is not declared as *int** *restrict* but as *int**.
By passing *xp* as argument to foo1, is the type of the object *xp* then
implicitly converted to (or merely interpreted as) *int* restrict *(because
of the argument type)*, i.e.* xp corresponds to the object *P *the standard
refers to?
int main() {
int x = 0;
int* xp = &x;
int res = foo2(&xp, &xp);
return 0;
}
---
@Richard, thank you for the alternative implementation. Is foo3 meant to be
optimized by GCC currently (I didn't manage to get GCC13.2 to do it)? Or is
it a hypothetical example that would allow GCC to optimize it?
int foo3(int *restrict * p, int *restrict * q)
{
int a;
*p = &a;
**q = 11;
**p = 12;
return **q;
}
Kind regards,
Ties
Op di 13 feb 2024 om 15:29 schreef Joseph Myers <josmy...@redhat.com>:
> On Tue, 13 Feb 2024, Ties Klappe via Gcc wrote:
>
> > int foo2(int *restrict *p, int *restrict *q)
> > {
> > **p = 10;
> > **q = 11;
> > return **p;
> > }
>
> In this case, *p and *q might be the same restricted pointer object. See
> the more detailed explanation at
> <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=14192#c8>.
>
> --
> Joseph S. Myers
> josmy...@redhat.com
>
>
