In article <3d4c2076@news.povray.org>, Micha Riser <mri### [at] gmxnet> 
wrote:

> No, unfortunately the Intel compiler (the only one that I have which does 
> vectorisation) does not recoginze this. You explicitly have to use a loop. 
> I have done rewriting vector.h in such a way. But I have no Pentium4 to 
> test it :( 

So it will only help operations on arrays then...seems like a stupid 
limitation. There isn't some compiler directive that could tell it what 
can be optimized?


> Todays g++ 3.1 does a good job in loop-unrolling. But with my modified 
> loop-using 'vector.h' it does still produce a slightly slower code (OK, 
> maybe I have also made some mistakes in the converting..)

Well, todays g++ 3.1 didn't exist 10 years ago. ;-)
With a modern compiler, I wouldn't expect it to be much slower, but how 
could you get any improvement? The SIMD instructions can't handle double 
precision math as far as I know...they would help colors, but not 
vectors.

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/

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