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Re: Vectorizing HIRLAM 5: Another one out of the "unhandled data-ref" grabbag.
- From: Dorit Naishlos <DORIT at il dot ibm dot com>
- To: Toon Moene <toon at moene dot indiv dot nluug dot nl>
- Cc: fortran at gcc dot gnu dot org, gcc at gcc dot gnu dot org
- Date: Fri, 21 Oct 2005 17:42:32 +0200
- Subject: Re: Vectorizing HIRLAM 5: Another one out of the "unhandled data-ref" grabbag.
Like HIRLAM 6, this is also an aliasing problem:
hilaram5.f90:4: note: not vectorized: can't determine dependence between
com.b[D.909_22] and (*a_8)[D.909_22]
hilaram5.f90:7: note: not vectorized: unhandled data-ref
hilaram5.f90:7: note: vectorized 0 loops in function.
dorit
> L.S.,
>
> This code:
>
> SUBROUTINE S(N)
> DIMENSION A(N), B(12)
> COMMON /COM/ B
> DO I = 1, 12
> A(I) = B(I)
> ENDDO
> PRINT*,A(1:12)
> END
>
> when compiled thusly:
>
> $ gfortran -g -S -O3 -ftree-vectorize -ftree-vectorizer-verbose=2 -
> msse2 vect5.f
>
> draws the dreaded "unhandled data-ref" message:
>
> vect5.f:4: note: not vectorized: unhandled data-ref
> vect5.f:4: note: vectorized 0 loops in function.
>
> Hmmm, this is rather common (pun intended) in old Fortran code.
> Why is this style "punished" by not being vectorizable ;-) ?
>
> Kind regards,
>
> --
> Toon Moene - e-mail: toon@moene.indiv.nluug.nl - phone: +31 346 214290
> Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
> A maintainer of GNU Fortran 95: http://gcc.gnu.org/fortran/