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

From: Segher Boessenkool <[email-masked]>
Date: Tue, 27 Feb 2018 14:42:43 -0600

On Tue, Feb 27, 2018 at 05:52:06PM +0200, Andy Shevchenko wrote:
> On Tue, Feb 27, 2018 at 9:44 AM, Mathieu Malaterre <[email-masked]> wrote:
> > On Tue, Feb 27, 2018 at 8:33 AM, Christophe LEROY
> > <[email-masked]> 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