Calculating array sizes in C - was: Re: Build regressions/improvements in v6.2-rc1

[Geert Uytterhoeven]

Hi Adrian,

On Tue, Jan 17, 2023 at 6:06 PM John Paul Adrian Glaubitz
<glaubitz at physik.fu-berlin.de> wrote:
> On 1/17/23 18:01, Geert Uytterhoeven wrote:
> > The issue is that some of the parameters are not arrays, but
> > NULL. E.g.:
> >
> > arch/sh/kernel/cpu/sh2/setup-sh7619.c:static
> > DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
> > arch/sh/kernel/cpu/sh2/setup-sh7619.c-                   NULL,
> > prio_registers, NULL);
>
> Isn't this supposed to be caught by this check:
>
>         a, __same_type(a, NULL)
>
> ?

Yeah, but gcc thinks it is smarter than us...
Probably it drops the test, assuming UB cannot happen.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds