Hi, sorry for my top-posting in last e-mail.
> hi, > > they should work completely independently from vectorization. It does not > matter if vectorizaton is already run or not, they will apply > if You enable them by flags. > > konrad > > > Dorit, > So it is correct to say that any loop that is vectorized is > removed from consideration for these other loop optimizations? > I ask because I am wondering if I should be testing these new > loop optimizations at -O2 in order to see their full effect > (without vectorization inhibiting their use). > Jack > > On Wed, Aug 13, 2008 at 05:08:53PM +0300, Dorit Nuzman wrote: >> > Can anyone explain the relationship between the current > vectorization >> > optimizations in the gcc trunk compiler and the new -floop-strip-mine, >> > -floop-interchange and -floop-block loop optimizations? Which takes >> > precedence and does one set block the other in any way? I would hope >> > that the new loop optimizations simply redefine the loops that are then >> > processed for vectorization so that both sets of optimizations can >> > be in effect at the same time. Thanks in advance for any clarifications >> > on how these optimizations interact with each other. >> By looking at passes.c I see that graphite is invoked before vectorizer. This means that first the loop optimizations -floop-interchange etc. will take place and then vectorizer will try to vectorize them. There is no direct interaction between those optimizations. I would be glad to see the results though. >> There's currently no interaction between the Graphite optimizations and >> vectorization. I don't know what considerations/cost-model Graphite uses >> before applying its optimizations, but vectorization is not one of them. > We >> are now starting to look into teaching Graphite to take into account >> factors that affect the applicability and profitability of vectorization, >> but this work is in a very initial stage. >> >> dorit >> >> > Jack > > > > konrad
