Re: [PATCH] i386: optimize memset of 6 and 8 bytes

[Stephen Hemminger]

On Fri, 17 Aug 2007 18:57:00 -0700
Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

> 
> On Fri, 2007-08-17 at 18:54 -0700, Stephen Hemminger wrote:
> > On Fri, 17 Aug 2007 18:49:34 -0700
> > Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
> > 
> > > 
> > > On Fri, 2007-08-17 at 16:50 -0700, Stephen Hemminger wrote:
> > > > Tne network code does memset for 6 and 8 byte values, that can easily
> > > > be optimized into simple assignments without string instructions.
> > > 
> > > 
> > > so... question.
> > > Why are we doing this by hand? Wouldn't gcc just generate this code in
> > > the first place (when using __builtin_memset)? I very much suspect it
> > > would (and if some version doesn't.... we really ought to get that
> > > fixed)
> > 
> > i386 and x86_64 are not using __builtin_memset, as least from the
> > code that I see generated.
> 
> .. maybe we should just fix it that way then?
> 
There probably is history behind the decision, like gcc problems
on some old compiler version.

-- 
Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx>
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