Re: Auto-vectorization: need to know what to expect

[EMAIL PROTECTED] wrote on 17/03/2008 21:08:43: > It might be nice to think about an option that automatically aligns large > arrays without having to do the declaration (or even have the vectorizer > override the alignment for statics/auto). The vectorizer is already doing this. Ira > > -- >

Re: Auto-vectorization: need to know what to expect

[EMAIL PROTECTED] wrote on 17/03/2008 19:33:23: > I have looked more closely at the messages generated by the gcc 4.3 > vectorizer > and it seems that they fall into two categories: > > 1) complaining about aligmnent. > > For example: > > Unknown alignment for access: D.33485 > Unknown alignment

Re: Auto-vectorization: need to know what to expect

Thanks a lot Michael for the detailed help! Thanks also n8tm, and sorry to have posted on the wrong list. Well that's a lot of food for thought and it'll keep me busy for some time, so thanks again to all, and bye! Benoit On Monday 17 March 2008 20:08:43 Michael Meissner wrote: > However, SSE i

Re: Auto-vectorization: need to know what to expect

On Mon, Mar 17, 2008 at 06:33:23PM +0100, Benoît Jacob wrote: > I have looked more closely at the messages generated by the gcc 4.3 > vectorizer > and it seems that they fall into two categories: > > 1) complaining about aligmnent. > > For example: > > Unknown alignment for access: D.33485 > U

Re: Auto-vectorization: need to know what to expect

OK. It's nontrivial as this uses a 2500-line c++ template library, but I'll do my best to come up with something self-contained. Cheers, Benoit On Monday 17 March 2008 18:51:57 Daniel Jacobowitz wrote: > On Mon, Mar 17, 2008 at 06:33:23PM +0100, Benoît Jacob wrote: > > I have looked more closely

Re: Auto-vectorization: need to know what to expect

On Mon, Mar 17, 2008 at 06:33:23PM +0100, Benoît Jacob wrote: > I have looked more closely at the messages generated by the gcc 4.3 > vectorizer > and it seems that they fall into two categories: The absolute best thing you can do in cases like this is to make a small program which shows the mes

Re: Auto-vectorization: need to know what to expect

I have looked more closely at the messages generated by the gcc 4.3 vectorizer and it seems that they fall into two categories: 1) complaining about aligmnent. For example: Unknown alignment for access: D.33485 Unknown alignment for access: m I don't understand, as all my data is statically al

Re: Auto-vectorization: need to know what to expect

Thanks Richard for the answer. It sounds like it's worth betting on gcc's autovectorizer and submitting bug reports -- so expect to hear again from us :) Cheers, Benoît On Monday 17 March 2008 15:59:21 Richard Guenther wrote: > On Mon, Mar 17, 2008 at 3:45 PM, Benoît Jacob <[EMAIL PROTECTED]> w

Re: Auto-vectorization: need to know what to expect

On Mon, Mar 17, 2008 at 03:45:49PM +0100, Benoît Jacob wrote: > Dear All, > > I am currently (co-)developing a Free (GPL/LGPL) C++ library for > vector/matrix > math. > > A major decision that we need to take is, what to do regarding vectorization > instructions (SSE). Either we rely on GCC to

Re: Auto-vectorization: need to know what to expect

On Mon, Mar 17, 2008 at 3:45 PM, Benoît Jacob <[EMAIL PROTECTED]> wrote: > Dear All, > > I am currently (co-)developing a Free (GPL/LGPL) C++ library for > vector/matrix > math. > > A major decision that we need to take is, what to do regarding vectorization > instructions (SSE). Either we rel

Auto-vectorization: need to know what to expect

Dear All, I am currently (co-)developing a Free (GPL/LGPL) C++ library for vector/matrix math. A major decision that we need to take is, what to do regarding vectorization instructions (SSE). Either we rely on GCC to auto-vectorize, or we control explicitly the vectorization using GCC's specia