Runtime errors with implicit do (fortran)

Accelerated Computing HPC Compilers Legacy PGI Compilers
1

I’m experiencing a problem using implicit dos (in a write statement) with allocatable arrays (allocated in a subroutine). For instance:

      Program Main
      Implicit None
      Real*8 CoorIn(3,23)
      Integer i,j
      Do j=1,Size(CoorIn,1)
        Do i=1,Size(CoorIn,2)
          CoorIn(j,i) = DBLE(i)
        End Do
      End Do
      Call PrintCoor(CoorIn,Size(CoorIn,2))
      End Program

      Subroutine PrintCoor(CoorIn,n)
      Implicit None
      Integer n
      Real*8 CoorIn(3,n)

      interface mma_allocate
        subroutine dmma_allo_2D(buffer,n1,n2,label)
          real*8, allocatable :: buffer(:,:)
          integer :: n1, n2
          character (len=*), optional :: label
        end subroutine
      end interface
      interface mma_deallocate
        subroutine dmma_free_2D(buffer)
          real*8, allocatable :: buffer(:,:)
        end subroutine
      end interface

      Real*8, Dimension(:,:), Allocatable :: Coor
      Integer :: i,j
      Call mma_allocate(Coor,3,n)
      Do j=1,3
        Do i=1,n
          Coor(j,i) = CoorIn(j,i)*DBLE(j)
        End Do
      End Do
      Write(6,*) 'Explicit loop'
      Do i=1,n
        Write (6,'(19X,3F11.5)') Coor(1,i),Coor(2,i),Coor(3,i)
      End Do
      Write(6,*) 'Implict loop'
      Write (6,'(19X,3F11.5)') ((Coor(j,i),j=1,3),i=1,n)
      Call mma_deallocate(Coor)
      Return
      End Subroutine

      subroutine dmma_allo_2D(buffer,n1,n2,label)
        implicit none
        real*8, allocatable :: buffer(:,:)
        integer :: n1, n2
        character (len=*), optional :: label
        allocate(buffer(n1,n2))
      end subroutine

      subroutine dmma_free_2D(buffer)
        implicit none
        real*8, allocatable :: buffer(:,:)
        deallocate(buffer)
      end subroutine

Compiling this code with “pgfortran test.f -i8” causes (when running the resulting binary):

 Implict loop
PGFIO-F-235/formatted write/unit=6/edit descriptor does not match item type.
 File name = stdout     formatted, sequential access   record = 26
 In source file test.f, at line number 44

Removing “-i8” or adding “-gopt” gets rid of the problem. A simplified version that does not have “printcoor” as a subroutine, but as the main program, causes segmentation faults. This happens with versions 14.7-0 and 16.7-0 at least.

Is there something intrinsically wrong with the code or is this a compiler bug? Other compilers like gfortran do not seem to have a problem with it.

2

This looks like a compiler bug. I have opened FS#23532 to track this.

As you found, -gopt will work around the problem. You can also declare the variables in the implied do statements as integer(4) until we get this fixed.

3

23532 - Implicit do variables in write statement, compiled with -i8, cause errors

has been fixed in the latest 17.1 release.

dave