Date: Tue, 27 Oct 2009 17:59:40 -0700 (PDT)
Message-Id: <20091027.175940.209239217.davem@davemloft.net>
To: mingo@elte.hu
Cc: lethal@linux-sh.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf tools: Kill off -Wcast-align
From: David Miller <davem@davemloft.net>
In-Reply-To: <20091027135025.GC32628@elte.hu>
References: <20091026094729.GB13517@linux-sh.org>
	<20091026.154055.07992945.davem@davemloft.net>
	<20091027135025.GC32628@elte.hu>
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From: Ingo Molnar <mingo@elte.hu>
Date: Tue, 27 Oct 2009 14:50:25 +0100

> Generally if you run into such issues in Sparc let us know so we can fix 
> it :-)

Sorry, I wanted to do a thorough analysis to make sure I understood
why it was warning, but I was too busy to do so.

In the end the issue is the kernel list.h macros like list_entry(),
and it would similarly trigger for things like container_of().

If you have a pointer to a structure with objects other than "long
double" then cast it to a pointer to a structure that does have a
"long double" in it, this increases the alignment of the type (from 8
to 16 bytes on sparc 32-bit).
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