Does SIMD optimization of GCC 3.4.6 work?

[Rene Rebe]

Hi,

On Wednesday 05 July 2006 20:26, Dave Korn wrote:

>   I believe Lionel's real problem is likely to be that he was hoping that
> turning on the "-mmx -sse -sse2 -3dnow" options would auto-vectorise his code
> for him.
> 
>   Lionel, (IIUIC) those options just /enable/ the use of the various SIMD
> features; they don't adjust your code to use those features if it doesn't do
> so already, so apart from a fairly small speed-up on some floating point
> operations that can be done more efficiently in the mmx unit, you shouldn't
> have been expecting to see much difference in the first place.

When you put it this way one should point him to "-ftree-vectorize" of
GCC 4.0 and 4.1 ...

Yours,

-- 
René Rebe - ExactCODE - Berlin (Europe / Germany)
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