[Bug fortran/104696] New: [12 Regression][OpenMP] Implicit mapping breaks struct mapping

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104696

            Bug ID: 104696
           Summary: [12 Regression][OpenMP] Implicit mapping breaks struct
                    mapping
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: openmp, wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org
                CC: cltang at gcc dot gnu.org, jakub at gcc dot gnu.org
  Target Milestone: ---

Created attachment 52519
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52519&action=edit
implicit.f90 - compile with -fopenmp and run with a non-shared-memory device.

In my understanding, the following is valid and should work.

However, it fails – and I bet it is due to the implicit mapping of 'var3'. The
code uses:

!$omp target map(to: var3%R(2)%d)
 ...

Printing on the host the  'loc (var3%R(2)%d)'  shows:
         21516C0
    7F51E5E001D8
    STOP 11

As var%R(2)%d  (or in the dump 'var3.r[1].d.data')  is now in device address
space,
accessing it after the target region crashes the program.


implicit.f90.005t.original:
  #pragma omp target
     map(to:var3.r[1].d [len: 88])
     map(to:*(struct t2[0:] *) var3.r[1].d.data [len: D.4243 * 4])
     map(always_pointer:(struct t2[0:] *) var3.r[1].d.data [pointer assign,
bias: 0])

implicit.f90.006t.gimple:
  #pragma omp target num_teams(1) thread_limit(0)
     map(tofrom:var3 [len: 440][implicit])
     map(to:var3.r[1].d [len: 88])
     map(to:MEM <struct t2[0:]> [(struct t2[0:] *)_9] [len: _8])
     map(always_pointer:var3.r[1].d.data [pointer assign, bias: 0])