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Re: RFC: Policy for arch specs

On Sun, 1 Jun 1997, Galen Hazelwood wrote:

> Raul Miller wrote:
> > 
> > On May 31, Galen Hazelwood wrote
> > > Perhaps.  Anybody have any serious arguments?  I think the reason we
> > > configure gcc as i486 is so it automatically optimizes for the 486; it's
> > > a good middle ground.
> > 
> > If I remember right, configuring for pentium leaves an executable
> > that might not run on 386 or 486.
> > 
> If gcc actually _did_ any pentium optimizations, that might be true. 
> Unfortunately, we don't get that until 2.8.  (still waiting...)

On every compiler I have used they don't actually use pentium
instructions. The optimization is soley from choosing order and
instructions based on clock cycle considerations and with pentiums,
pipelining too.

So code optimized for the pentium will run on a 386, but the timings will
not be as good for code optimized for the 386.

Now, if GCC is weird and decided to use 486, P5 or P6 specific
instructions (are there any new general use ones in the P5?) then this
might be a problem. 

BTW, anyone know when 2.8 is due?


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