| Message ID | f42f2366-957a-fefd-e6c5-41d88efd8802@codesourcery.com |
|---|---|
| State | New |
| Headers | show |
Am 14.07.2017 um 16:11 schrieb Cesar Philippidis: > This patch teaches the fortran FE to allow deferred-shape pointers to be > used in OpenACC data clauses. While the spec states that arrays must be > contiguous, I believe that is a run-time requirement, not a compile > time. The intent behind OpenACC is to have the programmer sprinkle a > minimum amount of ACC directives on their existing code base, and have > the compiler generate offloading code. In this case, the deferred-shape > pointer check was preventing working code from compiling. It is possible to declare a pointer with the contiguous attribute. Is there a reason that this cannot be used in general= > I was considering relaxing the error to a warning, but I ended up > deciding this should be a run-time failure, if there is one. What happens - silent wrong-code or indeed a run-time error which lets the user know what is wrong? > Is this OK for trunk? I tested it on x86_64 with nvptx offloading. Does any of the gfortran maintaiers have access to a machine which allows nvptx offloading? I lack both the hardware and the know-how :-) Regards Thomas
On 07/16/2017 10:28 AM, Thomas Koenig wrote: > Am 14.07.2017 um 16:11 schrieb Cesar Philippidis: >> This patch teaches the fortran FE to allow deferred-shape pointers to be >> used in OpenACC data clauses. While the spec states that arrays must be >> contiguous, I believe that is a run-time requirement, not a compile >> time. The intent behind OpenACC is to have the programmer sprinkle a >> minimum amount of ACC directives on their existing code base, and have >> the compiler generate offloading code. In this case, the deferred-shape >> pointer check was preventing working code from compiling. > > It is possible to declare a pointer with the contiguous attribute. > Is there a reason that this cannot be used in general= That's a good point. But some users don't want to modify their programs more beyond adding OpenACC directives. >> I was considering relaxing the error to a warning, but I ended up >> deciding this should be a run-time failure, if there is one. > > What happens - silent wrong-code or indeed a run-time error which > lets the user know what is wrong? It would be a run-time error, like a segmentation fault. >> Is this OK for trunk? I tested it on x86_64 with nvptx offloading. > > Does any of the gfortran maintaiers have access to a machine which > allows nvptx offloading? I lack both the hardware and the know-how :-) I don't know. Cesar
Am 17.07.2017 um 00:31 schrieb Cesar Philippidis: > On 07/16/2017 10:28 AM, Thomas Koenig wrote: >> It is possible to declare a pointer with the contiguous attribute. >> Is there a reason that this cannot be used in general= > > That's a good point. But some users don't want to modify their programs > more beyond adding OpenACC directives. Hm, I can understand that, at least partially, because CONTIGUOUS is a F2008 feature which my be rejected by compilers which do not implement it. >>> I was considering relaxing the error to a warning, but I ended up >>> deciding this should be a run-time failure, if there is one. >> >> What happens - silent wrong-code or indeed a run-time error which >> lets the user know what is wrong? > > It would be a run-time error, like a segmentation fault. What do you think about changing it into a warning enabled with -Wall? OK if you agree, otherwise we can continue the discussion. Regards Thomas
2017-07-14 Cesar Philippidis <cesar@codesourcery.com> gcc/fortran/ * openmp.c (check_array_not_assumed): Don't error on noncontiguous deferred-shape pointers. gcc/testsuite/ * gfortran.dg/goacc/deferred-shape-pointer.f90: New test. diff --git a/gcc/fortran/openmp.c b/gcc/fortran/openmp.c index 8400354181c..f08a37e0d89 100644 --- a/gcc/fortran/openmp.c +++ b/gcc/fortran/openmp.c @@ -3774,10 +3774,6 @@ check_array_not_assumed (gfc_symbol *sym, locus loc, const char *name) if (sym->as && sym->as->type == AS_ASSUMED_RANK) gfc_error ("Assumed rank array %qs in %s clause at %L", sym->name, name, &loc); - if (sym->as && sym->as->type == AS_DEFERRED && sym->attr.pointer - && !sym->attr.contiguous) - gfc_error ("Noncontiguous deferred shape array %qs in %s clause at %L", - sym->name, name, &loc); } static void diff --git a/gcc/testsuite/gfortran.dg/goacc/deferred-shape-pointer.f90 b/gcc/testsuite/gfortran.dg/goacc/deferred-shape-pointer.f90 new file mode 100644 index 00000000000..e0d0b8dd916 --- /dev/null +++ b/gcc/testsuite/gfortran.dg/goacc/deferred-shape-pointer.f90 @@ -0,0 +1,20 @@ +! Test support of deferred-shape pointers. + +subroutine foo (x, y, z) + implicit none + + integer :: y, z, i + integer,target :: x(y:z) + integer, pointer, dimension(:) :: px + + px => x + + !$acc data present(px) + !$acc end data + + !$acc parallel loop present(px) + do i = 1, z + px(i) = px(i) * 2 + end do + !$acc end parallel loop +end subroutine foo