From: Andrew Pinski <pinskia@physics.uc.edu>
To: Richard Guenther <rguenth@tat.physik.uni-tuebingen.de>
Cc: gcc@gcc.gnu.org
Subject: Re: Simple loops not interchanged?
Date: Fri, 10 Dec 2004 16:21:00 -0000 [thread overview]
Message-ID: <6E9B793A-4AC7-11D9-8186-000A95D692F4@physics.uc.edu> (raw)
In-Reply-To: <Pine.LNX.4.44.0412101616530.4584-100000@alwazn.tat.physik.uni-tuebingen.de>
On Dec 10, 2004, at 10:36 AM, Richard Guenther wrote:
> Hi!
>
> I expected -ftree-loop-linear to exchange loops in
>
> double foo(double *a)
> {
> int i,j;
> double r = 0.0;
> for (i=0; i<8; ++i)
> for (j=0; j<8; ++j)
> r += a[j*8+i];
> return r;
> }
>
> but it tells me (regardless of loop order) that
> "Won't transform loop. Optimal transform is the identity transform"
> which I cannot believe, obviously.
>
> What's going wrong here?
First file a bug.
Second the loop linearizer loves ARRAY_REF and not INDIRECT_REF
for 4.1, we should be able to get MEM_REF which is like ARRAY_REF
and the loop lineaerizer will just do its job.
I tested the theory by having a local array instead of passing
the pointer.
Thanks,
Andrew Pinski
next prev parent reply other threads:[~2004-12-10 16:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-10 15:36 Richard Guenther
2004-12-10 16:21 ` Andrew Pinski [this message]
2004-12-10 16:39 ` Daniel Berlin
2004-12-10 16:34 ` Daniel Berlin
2004-12-12 3:58 ` [autovect][PATCH]: " Daniel Berlin
2004-12-12 17:59 ` Devang Patel
2004-12-12 18:02 ` Daniel Berlin
2004-12-13 9:46 ` Sebastian Pop
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