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Date:   Mon, 14 Feb 2022 10:52:13 +0000
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
From:   Simon Ser <contact@emersion.fr>
Cc:     Thomas Zimmermann <tzimmermann@suse.de>,
        linux-fbdev@vger.kernel.org, David Airlie <airlied@linux.ie>,
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        linux-kernel@vger.kernel.org,
        =?utf-8?Q?Noralf_Tr=C3=B8nnes?= <noralf@tronnes.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        dri-devel@lists.freedesktop.org, Sam Ravnborg <sam@ravnborg.org>,
        Maxime Ripard <maxime@cerno.tech>
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Subject: Re: [PATCH v4 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line()
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On Monday, February 14th, 2022 at 11:38, Andy Shevchenko <andriy.shevchenko=
@linux.intel.com> wrote:

> > > > IMO *always* prefer a for loop over while or do-while.
> > > >
> > > > The for (i =3D 0; i < N; i++) is such a strong paradigm in C. You
> > > > instantly know how many times you're going to loop, at a glance. No=
t so
> > > > with with the alternatives, which should be used sparingly.
> > >
> > > while () {}  _is_ a paradigm, for-loop is syntax sugar on top of it.
> >
> > Naw, that's not true.
>
> In the section 3.5 "Loops - While and For" in "The C Programming
> Language" 2nd by K&R, the authors said:
>
> =09The for statement ... is equivalent to ... while..."
>
> They said that for is equivalent to while, and not otherwise.
>
> Also, syntax sugar by definition declares something that can be written a=
s
> a single line of code, which usually is done using more (not always).

arr[i] is syntaxic sugar for *(arr + i), yet we keep writing the former,
because it's way more readable. The same goes for the for vs. while loops.
It may be obvious for you because you're a C guru, but to me it just obfusc=
ates
the code. Too many C projects end up becoming completely unreadable because=
 of
patterns like these.

Idiomatic C code isn't written by doing pointless micro-optimizations.