Re: [PATCH 01/21] powerpc: Remove warning on array size when empty

From: Segher Boessenkool
Date: Tue Feb 27 2018 - 15:43:26 EST


On Tue, Feb 27, 2018 at 05:52:06PM +0200, Andy Shevchenko wrote:
> On Tue, Feb 27, 2018 at 9:44 AM, Mathieu Malaterre <malat@xxxxxxxxxx> wrote:
> > On Tue, Feb 27, 2018 at 8:33 AM, Christophe LEROY
> > <christophe.leroy@xxxxxx> wrote:
>
> >>>>> Much simpler is just add
> >>>>>
> >>>>> if (ARRAY_SIZE() == 0)
> >>>>> return;
>
> >> Or add in front:
> >> if (!ARRAY_SIZE(feature_properties))
> >> return;
> >
> > (not tested) I believe the compiler still go over the for() loop and
> > will complain about the original unsigned comparison.
>
> Did you run tests? Did you look into object file?
>
> In kernel we much rely on the compiling away the code which is
> deterministically not in use.
> Here I'm pretty sure it will compile away entire function.

It does, but it also still warns (this warning is done very early in the
compiler pipeline).


Segher