> Richard Guenther <[EMAIL PROTECTED]> wrote on 05/02/2007 18:16:05: > > > On Mon, 5 Feb 2007, Jan Hubicka wrote: > ... > > > Did you run some benchmarks? > > > > Not yet - I'm looking at the C++ SPEC 2006 benchmarks at the moment > > and using vectorization there seems to do a lot of collateral damage > > (maybe not measurable though). > > > > Interesting. In SPEC 2000 there is also a hot small loop in the only C++ > benchmark (eon), which get vectorized, and as a result degrades > performance. We really should not vectorize such loops, and the solution > is: > 1. FORNOW: use --param min-vect-loop-bound=2 (or some value greater than > 0).
Well, if Tomas manage to post his patch, I think the eon case is dealt with there too (the loop is just internal loop to zero tiny vector or something like that as long as I can remember) Honza > 2. SOON: rely on the vectorizer to do the cost analysis and decide not to > vectorize such loops, using a cost model - this is in the works. > > dorit > > > Richard. > > > > -- > > Richard Guenther <[EMAIL PROTECTED]> > > Novell / SUSE Labs
