[Bug fortran/33904] New: OpenMP: Default(shared) and wrong "lastprivate variable is private in outer context"
burnus at gcc dot gnu dot org
gcc-bugzilla@gcc.gnu.org
Fri Oct 26 07:41:00 GMT 2007
Reported by Vasileios Liaskovitis,
http://gcc.gnu.org/ml/fortran/2007-10/msg00339.html
The following valid program gives
"error: lastprivate variable "i2" is private in outer context"
------------------------------------
SUBROUTINE foo(a, b, n)
DOUBLE PRECISION a, b
INTEGER*8 i1, i2, i3, n
DIMENSION a(n,n,n), b(n,n,n)
!$OMP PARALLEL
!$OMP+DEFAULT(SHARED)
!$OMP+PRIVATE(I3)
!$OMP DO
!$OMP+LASTPRIVATE(I1,I2)
DO i3 = 2, n-1, 1
DO i2 = 2, n-1, 1
DO i1 = 2, n-1, 1
a(i1, i2, i3) = b(i1, i2, i3);
600 CONTINUE
ENDDO
ENDDO
ENDDO
!$OMP END DO NOWAIT
!$OMP END PARALLEL
RETURN
END
------------------------------------
Vasilis wrote:
I believe this code is compliant with the OPENMP 2.5 spec, since the
DEFAULT(SHARED) clause should make the scope of i1, i2 shared in the
enclosing parallel region. Pathscale 3.0, PGI 7.0.6 and Intel 10.0.026
compile the above code successfully.
Replacing:
!$OMP+DEFAULT(SHARED)
with:
!$OMP+SHARED(I1,I2)
makes the code compile successfully with gfortran.
Alternatively, keeping DEFAULT(SHARED) and fusing the OMP PARALLEL
clause with the OMP DO clause (i.e. using OMP PARALLEL DO) also solves
the problem.
(this testcase is derived from a benchmark suite that doesn't allow
source code modifications. gfortran should be able to compile this with
no code changes - if this is indeed openmp-compliant code)
Could this behavior be due to the following libgomp patch not getting
all necessary information from the fortran front-end?
http://gcc.gnu.org/ml/gcc-patches/2007-01/msg01940.html
--
Summary: OpenMP: Default(shared) and wrong "lastprivate variable
is private in outer context"
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Keywords: rejects-valid, openmp
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: burnus at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33904
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