Re: [PATCH] Matrix Flattening and Transposing optimizations

[Toon Moene <toon at moene dot indiv dot nluug dot nl>]

Richard Guenther wrote:

> On 4/28/07, I wrote:

> > Razya, does your patch does the right thing to reorder:
> >
> >        SUBROUTINE SUB(A, B, N, M)
> >        DIMENSION A(N, M), B(N, M)
> >        DO I = 1, N
> >           DO J = 1, M
> >              A(I, J) = B(I, J)
> >           ENDDO
> >        ENDDO
> >        END
> >
> > Currently, it doesn't vectorize because the loops are not in the right
> > order.  Note that you don't have to "reorganize the matrix [layout]" to
> > get this right - just reorder the loops.
>
> Isn't that what -ftree-loop-linear is for?

Apparently not:

$ /usr/snp/bin/gfortran -S -g -O2 -ftree-vectorize 
-ftree-vectorizer-verbose=2 -ftree-loop-linear vect6.f

vect6.f:4: note: not vectorized: unhandled data-ref
vect6.f:1: note: vectorized 0 loops in function.

$ /usr/snp/bin/gfortran -v
Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: ../trunk/configure --prefix=/usr/snp/ 
--disable-multilib --disable-nls --enable-languages=fortran
Thread model: posix
gcc version 4.3.0 20070428 (experimental)

--
Toon Moene - e-mail: toon@moene.indiv.nluug.nl - phone: +31 346 214290
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At home: http://moene.indiv.nluug.nl/~toon/
Who's working on GNU Fortran: 
http://gcc.gnu.org/ml/gcc/2007-01/msg00059.html