[Bug fortran/102891] New: Passing real part of complex type component using w%z%re to a subroutine gives erroneous value of dummy argument

[Bug fortran/102891] New: Passing real part of complex type component using w%z%re to a subroutine gives erroneous value of dummy argument

[oeyvindyr at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102891

            Bug ID: 102891
           Summary: Passing real part of complex type component using
                    w%z%re to a subroutine gives erroneous value of dummy
                    argument
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: oeyvindyr at hotmail dot com
  Target Milestone: ---

Created attachment 51653
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51653&action=edit
minimal fortran program

The attached minimal program prints the real part of a complex allocatable type
component in two ways: 1) "print*,w%z%re" in the caller 2) By passing w%z%re to
a subroutine that prints the array. The printed numbers are different in the
two cases, and it seems that the dummy argument in the called subroutine gets
an incorrect stride of 1, whereas it should be 2 for the real part of a complex
array.

Compiling with ifort gives the expected result and no warnings.

[Bug fortran/102891] Passing real part of complex type component using w%z%re to a subroutine gives erroneous value of dummy argument

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102891

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |anlauf at gcc dot gnu.org
   Last reconfirmed|                            |2021-10-22

--- Comment #1 from anlauf at gcc dot gnu.org ---
Confirmed.

Interestingly, replacing the line

  call print_arr(w%z%re)

by

  call print_arr([w%z%re])

works around the issue.

[Bug fortran/102891] Passing real part of complex type component using w%z%re to a subroutine gives erroneous value of dummy argument

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102891

--- Comment #2 from anlauf at gcc dot gnu.org ---
Adding to main the lines

  print *, size (transfer ( w%z%re ,[1.0_dp]))
  print *, size (transfer ([w%z%re],[1.0_dp]))

prints

           4
           2

whereas e.g.

  print *, size (transfer ( real (w%z, kind (w%z%re)) ,[1.0_dp]))
  print *, size (transfer ([real (w%z, kind (w%z%re))],[1.0_dp]))

prints

           2
           2

The issue is likely with the combination of array/array constructor and
the inquiry %re .

Possibly related: pr102599.