Re: [boost] [OT?] SIMD and Auto-Vectorization (was Re: How to structurate libraries ?)

Subject: Re: [boost] [OT?] SIMD and Auto-Vectorization (was Re: How to structurate libraries ?)
From: David A. Greene (greened_at_[hidden])
Date: 2009-01-22 15:53:50

On Wednesday 21 January 2009 20:07, Michael Marcin wrote:

> > Well, the whole discussion is about "optimal."  If one doesn't care about
> > "optimal" then a compiler will do just fine all the time and there's no
> > need for a DSEL, asm or ugly gcc intrinsics.
>
> What if we replace optimal with optimized?
>
> Surely library code than gives a 4x speedup is desirable to have even if
> you can hand generate code that gives you a 5x. Getting a 4x speedup
> over naive simd-less in simple vector operations and still being able to
> concentrate on the problem at hand instead of low level optimization
> details sounds fantastic to me.

Agreed.  I'm under the impression that Joel wants to get 5x through a 
DSEL-based code generator.  I'm not sure it's worthwhile in the general case.
It may be worthwhile in highly specialized cases.

                                       -Dave