Date: Thu, 19 Nov 2009 10:43:41 -0800 (PST)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andrew Haley <aph@redhat.com>
cc: Richard Guenther <richard.guenther@gmail.com>, rostedt@goodmis.org,
       Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
       "H. Peter Anvin" <hpa@zytor.com>, LKML <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Heiko Carstens <heiko.carstens@de.ibm.com>, feng.tang@intel.com,
       Fr??d??ric Weisbecker <fweisbec@gmail.com>,
       Peter Zijlstra <peterz@infradead.org>, jakub@redhat.com,
       gcc@gcc.gnu.org
Subject: Re: BUG: GCC-4.4.x changes the function frame on some functions
In-Reply-To: <alpine.LFD.2.00.0911191039470.2793@localhost.localdomain>
Message-ID: <alpine.LFD.2.00.0911191041471.2793@localhost.localdomain>
References: <alpine.LFD.2.00.0911181933540.24119@localhost.localdomain>   <tip-887a29f59b93cf54e21814869a4ab6e80b6fa623@git.kernel.org>   <20091119072040.GA23579@elte.hu>   <alpine.LFD.2.00.0911191053390.24119@localhost.localdomain>  
 <alpine.LFD.2.00.0911191423190.24119@localhost.localdomain>   <alpine.LFD.2.00.0911191607440.24119@localhost.localdomain>   <alpine.LFD.2.00.0911190934070.2793@localhost.localdomain>   <1258653562.22249.682.camel@gandalf.stny.rr.com>
 <84fc9c000911191003t244eb864o3d5b355ab5485f@mail.gmail.com> <4B058CCD.8050605@redhat.com> <alpine.LFD.2.00.0911191039470.2793@localhost.localdomain>
User-Agent: Alpine 2.00 (LFD 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1110
Lines: 25


On Thu, 19 Nov 2009, Linus Torvalds wrote:
> 
> Oh Gods, are we back to gcc people saying "sure, we do stupid things, but 
> it's allowed, so we don't consider it a bug because it doesn't matter that 
> real people care about real life, we only care about some paper, and real 
> life doesn't matter, if it's 'undefined' we can make our idiotic choices 
> regardless of what people need, and regardless of whether it actually 
> generates better code or not".

Put another way: the stack alignment itself may not be a bug, but gcc 
generating God-awful code for the mcount handling that results in problems 
in real life sure as hell is *stupid* enough to be called a bug.

I bet other people than just the kernel use the mcount hook for subtler 
things than just doing profiles. And even if they don't, the quoted code 
generation is just crazy _crap_.

		Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/