GCC Status (2004-08-09)

[Scott Robert Ladd]

I've been away from GCC for a several weeks, on other business. I've 
just returned, and will be applying various benchmarks in the next week 
or so to GCC 3.5 and earlier.

mitchell@mail.codesourcery.com wrote:
> In addition, it's not entirely clear how good the code generated from
> GCC 3.5 is relative to the code generated from earlier releases.  I've
> heard everything from "much better" to "much worse"; my current guess
> is "not too different".

I think the best characterization is "on average, not too different". In 
some cases, 3.5 does better than 3.4 (and earlier); in other situations, 
the opposite is true. The bottom line is that 3.5 does not (at this 
time) provide siginificant improvements in generate code speed.

> In any case, I'd like to start with (1).  The vectorizer is unlikely
> to do any harm; the most frequent complaint I've heard is that it
> doesn't vectorize enough loops.  And, vectorization -- even if
> somewhat incomplete -- will be an exciting feature for GCC 3.5 that
> will show what all the new optimization infrastructure can do.

I completely agree. Having a vectorizer (perfect or not) will eliminate 
a common PR hit against GCC in certain circles.

-- 
Scott Robert Ladd
Coyote Gulch Productions (http://www.coyotegulch.com)
Software Invention for High-Performance Computing