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Date:   Mon, 30 Sep 2019 00:09:08 +0300
From:   Alexey Dobriyan <adobriyan@gmail.com>
To:     Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc:     akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com,
        rodrigo.vivi@intel.com, intel-gfx@lists.freedesktop.org,
        rostedt@goodmis.org, mingo@redhat.com
Subject: Re: [PATCH] Make is_signed_type() simpler
Message-ID: <20190929210908.GA14456@avx2>
References: <20190929200619.GA12851@avx2>
 <f99ca43d-1ba2-95fb-b90f-6706a06f8ce6@rasmusvillemoes.dk>
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On Sun, Sep 29, 2019 at 10:21:48PM +0200, Rasmus Villemoes wrote:
> On 29/09/2019 22.06, Alexey Dobriyan wrote:
> > * Simply compare -1 with 0,
> > * Drop unnecessary parenthesis sets
> > 
> > -#define is_signed_type(type)       (((type)(-1)) < (type)1)
> > +#define is_signed_type(type)       ((type)-1 < 0)
> 
> NAK. I wrote it that way to avoid -Wtautological-compare when type is
> unsigned.

Was is W=1?

godbolt doesn't show it with just -Wall

	https://godbolt.org/z/kCA7mm

And the warning which found i915 case is -Wextra not -Wtautological-compare.