[Bug fortran/52227] New: TARGET attribute mishandled in polymorphic types

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52227

             Bug #: 52227
           Summary: TARGET attribute mishandled in polymorphic types
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: missed-optimization, rejects-valid, wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org
                CC: pault@gcc.gnu.org


Seemingly, the TARGET attribute is mishandled. The following program gives:

  target :: a,b
              1
  Error: Duplicate TARGET attribute specified at (1)


Thus, there is a rejects valid issue. However, depending which variable is
declared first, there is also a potential wrong-code issue as a TARGET variable
might still get the "restrict" qualifier in the gimple representation. Or a
nontarget might get no "restricted", which is a missed optimization.


The other attributes have to be checked as well. That includes VOLATILE and
ASYNCHRONOUS. It might be enough that the variable has the proper attribute and
that such the attribute is properly propagated; at least volatile seems to be
handled correctly, but it should be re-checked. (Asynchronous is currently not
used on gimple level, cf. PR49733/PR25829; nevertheless, it should be
propagated correctly.)

I think the other attributes are either related to
dimension/allocatable/pointer and already taken care of - or are dummy-related
attributes such as optional, value (cf. PR51284), intent etc.



type t
end type t

class(t), allocatable :: a(:), b(:)
target :: a,b
select type (a)
  type is (t)
   select type (b)
     type is (t)
       a(1) = b(1)
   end select
end select
end