SSE conversion optimization

[H.J. Lu]

On Sat, Sep 08, 2007 at 06:56:35PM -0500, Jagasia, Harsha wrote:
> Hi Honza, H.J,
> >> Amdfam10 preffers doing packed conversions destinating SSE register
> >rather than scalar.
> >> This means basically following replacments:
> >>
> >> -      cvtsi2sd -> movd + cvtdq2pd
> >> -      cvtsi2ss -> movd + cvtdq2ps
> >
> >Can you disable them for -mtune=generic if an extra pair of
> >memory load/store is added?
> 
> Instead of disabling would it help to do the below?
> 
> Replace:
> cvtsi2sd reg32, xmm
> with:
> mov reg32, mem32
> cvtsi2sd mem32, xmm
> 
> This could work for cvtsi2ss and could also work for reg64.
> 

That is one kind of extra pair for memory load/store I was referring
to. It is bad for Core 2 Duo.


H.J.