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)
http://exactcode.de | http://t2-project.org | http://rene.rebe.name
+49 (0)30 / 255 897 45
