linux-kernel - Re: [PATCH] trivial: the memset operation on a automatic array variable should be optimized out by data initialization

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Date:	Sun, 24 Jun 2007 17:09:16 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	Benjamin LaHaise <bcrl@...ck.org>
Cc:	Oleg Verych <olecom@...wer.upol.cz>, rae l <crquan@...il.com>,
	trivial@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] trivial: the memset operation on a automatic array
	variable should be optimized out by data initialization

On Sun, 2007-06-24 at 19:23 -0400, Benjamin LaHaise wrote:
> On Sun, Jun 24, 2007 at 03:15:17PM -0700, Arjan van de Ven wrote:
> > we should just alias our memset to the __builtin one, and then provide a
> > generic one from lib/ for the cases gcc needs to do a fallback.
> 
> The last time I checked, gcc generated horrible badly performing code for 
> builtin memset/memcpy() when -Os is specified.

if you care about the last cycle, don't specify -Os but -O2.
simple as that... you get what you tell the compiler you want.

-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
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