> On Fri, Jun 15, 2007 at 11:33:52PM -0400, Vladimir N. Makarov wrote: > > H. J. Lu wrote: > > ... > > > > > > > > A mount ago I did some measurements of the effect of the vectorizer for
> > Core2 in 64-bit mode. Unfortunately, I saw small improvement (as I > > remember less than 1% for SPECInt2000). > > Vectorizer works only when there are vector instructions available > which vectorizer can take advantage of. Adding -mssse3 should make > vectorizer to work a little bit better. SSE4 will improve vectorizer > even more. > > > > > Vectorizer is a big a project and may be we will see more improvements > > in future. They promissed implement SLP two years ago and now I see it > > happens. It would be nice to see it not only in loops. > > There are quite a few known simple cases which vectorizer fails to > vectorize. by "known" you mean there are open missed-optimization PRs for them? (if not - please feel free to open PRs for them!) thanks, dorit > Also, not all x86 vector instructions are supported by > vectorizer. > > > H.J.
