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Re: vectorization, -floop-strip-mine, -floop-block and -floop-interchange
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
From: Jack Howarth <howarth@bromo.msbb.uc.edu>
To: Dorit Nuzman/Haifa/IBM@IBMIL
Cc: gcc@gcc.gnu.org, Konrad Trifunovic/Haifa/Contr/IBM@IBMIL
Date: 13/08/2008 17:24
Subject: Re: vectorization, -floop-strip-mine, -floop-block and -floop-interchange
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.
>
> 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