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Date: Mon, 30 Jun 2014 22:15:55 +0200
From: Marius Strobl <marius@alchemy.franken.de>
To: John Baldwin <jhb@freebsd.org>
Subject: Re: svn commit: r268055 - head/sys/sys
Message-ID: <20140630201555.GE7615@alchemy.franken.de>
References: <201406301811.s5UIBMxh036571@svn.freebsd.org>
 <201406301437.08687.jhb@freebsd.org> <53B1AFDE.30104@selasky.org>
 <201406301447.21620.jhb@freebsd.org>
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 (alchemy.franken.de [0.0.0.0]); Mon, 30 Jun 2014 22:15:55 +0200 (CEST)
Cc: Hans Petter Selasky <hps@selasky.org>, svn-src-head@freebsd.org,
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On Mon, Jun 30, 2014 at 02:47:21PM -0400, John Baldwin wrote:
> On Monday, June 30, 2014 2:43:42 pm Hans Petter Selasky wrote:
> > On 06/30/14 20:37, John Baldwin wrote:
> > > Reindenting the whitespace made this diff harder to read.  Why hasn't this
> > > been a problem before on powerpc64?
> > 
> > Hi,
> > 
> > This has not been a problem before, because producers of DATA_SET()'s 
> > were using syntax along these lines:
> > 
> > static int test2;
> > static int test3;
> > 
> > DATA_SET(test, test2);
> > DATA_SET(test, test3);
> > 
> > Now if you change this simple code to:
> > 
> > static int test2;
> > int test3;
> > 
> > DATA_SET(test, test2);
> > DATA_SET(test, test3);
> > 
> > It breaks on powerpc64. Should be very easy to reproduce.
> > 
> > The problem with SYSCTL's is that some are global and some are not. 
> > Before an indirect pointer was hiding this problem from appearing.
> > 
> > Do you see? Or do you want me to explain more.
> 
> Ahh, ok.  Seems odd that this sort of thing would be ppc64-specific however.
> 

Apparently it isn't and has also has shown up on at least ia64:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31490

Marius