A bit of vector extension documentation

[Diego Novillo]

On Fri, 28 Sep 2001, David Edelsohn wrote:

> >>>>> Richard Henderson writes:
> 
> Richard> On Fri, Sep 28, 2001 at 11:48:31AM -0400, Daniel Berlin wrote:
> >> It's based on the algorithms in the paper "Exploiting superword level 
> >> parallelism with multimedia instruction sets"
> >> http://www.acm.org/pubs/citations/proceedings/pldi/349299/p145-larsen/
> 
> Richard> Yes, I've seen that one.  While a nice starting point, I don't 
> Richard> think it's as powerful as some of the other loop-based vectorization
> Richard> algorithms.
> 
> 	I thought the point of the paper is that it is a generalization
> that does not require loops.  For SIMD, as opposed to vector,
> architectures, it might be better because it can take advantage of such
> instructions without the loop setup overhead.
> 
Yes, the paper does not attempt to design a vectorizing compiler.
It merely points out that in several cases you can get away with
converting sequence of expressions into SIMD instructions.  They
do have the limitation of working on single basic blocks, though.

Diego.