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Date:   Sat, 23 Jul 2022 14:22:11 -0500
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Michal =?iso-8859-1?Q?Such=E1nek?= <msuchanek@suse.de>
Cc:     Jason Wang <wangborong@cdjrlc.com>, lkp@intel.com,
        linux-kernel@vger.kernel.org, npiggin@gmail.com,
        Julia.Lawall@inria.fr, paulus@samba.org, joel@jms.id.au,
        linuxppc-dev@lists.ozlabs.org, hbathini@linux.ibm.com
Subject: Re: [PATCH] powerpc: Remove the static variable initialisations to 0
Message-ID: <20220723192211.GP25951@gate.crashing.org>
References: <20220723092436.7149-1-wangborong@cdjrlc.com> <20220723133405.GF17705@kitsune.suse.cz>
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On Sat, Jul 23, 2022 at 03:34:05PM +0200, Michal Such?nek wrote:
> Hello,
> 
> On Sat, Jul 23, 2022 at 05:24:36PM +0800, Jason Wang wrote:
> > Initialise global and static variable to 0 is always unnecessary.
> > Remove the unnecessary initialisations.
> 
> Isn't this change also unnecessary?
> 
> Initializing to 0 does not affect correctness, or even any kind of
> semantics in any way.

It did make a difference when the kernel was still compiled with
-fcommon (which used to be the GCC default on most configurations, it is
traditional on Unix).  No explicit initialiser puts an object in .bss if
you use -fcommon.  This matters a bit for data layout.

> The current code is slightly easier to understand.
> 
> And changing the code introduces history noise for na gain.

Yup.

This does give you some code golf points of course ;-)


Segher