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Date:   Fri, 2 Feb 2018 16:50:22 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Jani Nikula <jani.nikula@linux.intel.com>
Cc:     Lukas Bulwahn <lukas.bulwahn@gmail.com>,
        Knut Omang <knut.omang@oracle.com>,
        Ozan Alpay <ozyalpy@gmail.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Ville =?iso-8859-1?Q?Syrj=E4l=E4?= 
        <ville.syrjala@linux.intel.com>, sil2review@lists.osadl.org,
        kernelnewbies@kernelnewbies.org, David Airlie <airlied@linux.ie>,
        intel-gfx@lists.freedesktop.org,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        llvmlinux@lists.linuxfoundation.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org
Subject: Re: clang warning: implicit conversion in intel_ddi.c:1481
Message-ID: <20180202155022.GA29918@kroah.com>
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 <87372jkcu5.fsf@intel.com>
 <alpine.DEB.2.20.1802021054500.13838@hsp>
 <20180202100613.GA21492@kroah.com>
 <87h8qzisbt.fsf@intel.com>
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On Fri, Feb 02, 2018 at 04:37:55PM +0200, Jani Nikula wrote:
> On Fri, 02 Feb 2018, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Fri, Feb 02, 2018 at 12:44:38PM +0200, Jani Nikula wrote:
> >> 
> >> +Knut, Fengguang
> >> 
> >> On Fri, 02 Feb 2018, Greg KH <gregkh@linuxfoundation.org> wrote:
> >> > 	- If clang now builds the kernel "cleanly", yes, I want to take
> >> > 	  warning fixes in the stable tree.  And even better yet, if you
> >> > 	  keep working to ensure the tree is "clean", that would be
> >> > 	  wonderful.
> >> 
> >> So we can run sparse using 'make C=1' and friends, or other static
> >> analysis tools using 'make CHECK=foo C=1', as long as the passed command
> >> line params work. There was work by Knut to extend this make checker
> >> stuff [1]. Since mixing different HOSTCC's in a single workdir seems
> >> like a bad idea, I wonder how hard it would be to make clang work like
> >> this:
> >> 
> >> $ make CHECK=clang C=1
> >> 
> >> Or using Knut's wrapper. Feels like that could increase the use of clang
> >> for static analysis of patches.
> >
> > Why not just build with clang itself:
> > 	make CC=clang
> 
> Same as HOSTCC, mixing different CC's in a single build dir seems like a
> bad idea. Sure, everyone can setup a separate build dir for clang, but
> IMHO having 'make CHECK=clang C=1' work has least resistance. YMMV.

"O=some_output_dir" is your friend.  If you aren't doing that already
for your test builds, you don't know what you are missing :)

thanks,

greg k-h