Bugreport for the fortran compiler: Treatment of array bounds in the specification part

Hi all, some time ago I’ve faced an interesting difference in behaviour between different compilers.

Briefly, if there is a function, where in the specification part the ubounds/lbounds functions are used in the specification part, e.g.

Fullscreen1
2
3
4
 function justcopy(arr_in) 
   real, intent(in) :: arr_in(0:,:)
   real :: justcopy(0:ubound(arr_in,dim=1), 2:5) 
....
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
 function justcopy(arr_in) 
   real, intent(in) :: arr_in(0:,:)
   real :: justcopy(0:ubound(arr_in,dim=1), 2:5) 
....

the actual size of the declared array will be different, as if ubound is calculated before the declaration of the array.

See details here fortran-lang.discourse.group/.../3

My assumption is that such a behaviour is a bug.

Best regards,
Andrii

P.S. As of now I've tested this code

Fullscreen

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
program aocc_run_test
  implicit none
  real :: arr_in1(0:10, 2:5), arr1(0:10,2:5)
  integer  i, j
  do i=0,10
  do j=2,5
    arr_in1(i,j) = 1000*i+j
  end do
  end do
  call evaluate(arr_in1,arr1)
contains
  function justcopy(arr_in)
   implicit none
   real, intent(in) :: arr_in(0:,:)
   real :: justcopy(0:ubound(arr_in,dim=1), 2:5)  !This works for "A" GNU,Intel/InteLLVM,lfortran,NAG,IBM. Does not work for "B" AOCC, NVidia, ARM.
   !real :: justcopy(0:size(arr_in,dim=1)-1, 2:5) !This works for all compilers
   write(*,*) "arr_in, dim 1 (lb,ub,sz):", lbound(arr_in,dim=1),ubound(arr_in,dim=1),size(arr_in,1)
   write(*,*) "arr_in, dim 2 (lb,ub,sz):", lbound(arr_in,dim=2),ubound(arr_in,dim=2),size(arr_in,2)
   write(*,*) "justcp, dim 1 (lb,ub,sz):", lbound(justcopy,dim=1),ubound(justcopy,dim=1),size(justcopy,1)
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

program aocc_run_test
  implicit none
  real :: arr_in1(0:10, 2:5), arr1(0:10,2:5)
  integer  i, j
  do i=0,10
  do j=2,5
    arr_in1(i,j) = 1000*i+j
  end do
  end do

  call evaluate(arr_in1,arr1)
contains

  function justcopy(arr_in)
   implicit none
   real, intent(in) :: arr_in(0:,:)
   real :: justcopy(0:ubound(arr_in,dim=1), 2:5)  !This works for "A" GNU,Intel/InteLLVM,lfortran,NAG,IBM. Does not work for "B" AOCC, NVidia, ARM.
   !real :: justcopy(0:size(arr_in,dim=1)-1, 2:5) !This works for all compilers
   write(*,*) "arr_in, dim 1 (lb,ub,sz):", lbound(arr_in,dim=1),ubound(arr_in,dim=1),size(arr_in,1)
   write(*,*) "arr_in, dim 2 (lb,ub,sz):", lbound(arr_in,dim=2),ubound(arr_in,dim=2),size(arr_in,2)
   write(*,*) "justcp, dim 1 (lb,ub,sz):", lbound(justcopy,dim=1),ubound(justcopy,dim=1),size(justcopy,1)
   write(*,*) "justcp, dim 2 (lb,ub,sz):", lbound(justcopy,dim=2),ubound(justcopy,dim=2),size(justcopy,2)
   justcopy=arr_in
  end function justcopy
 
  subroutine evaluate(arr_in1,arr_out1)
    implicit none
    real,    intent(in)  :: arr_in1(:,:)
    real,    intent(out) :: arr_out1(:,:)
    real, allocatable  :: X(:,:)

    !arr_out1 = justcopy(arr_in1)
    X = justcopy(arr_in1)       
    write(*,*) "X     , dim 1 (lb,ub,sz):", lbound(X,dim=1),ubound(X,dim=1),size(X,1)
    write(*,*) "X     , dim 2 (lb,ub,sz):", lbound(X,dim=2),ubound(X,dim=2),size(X,2)

    if (size(X,1) /= size(arr_in1,1)) then
       print "(A,I2,A,I2)","Error: size of X(dim1)=",size(X,1),&
                           " was not equal to size of arr_in1(dim1)=",size(arr_in1,1)
      error stop 1
    end if
    
    arr_out1 = X
  end subroutine evaluate  
end program aocc_run_test

with 24.10.1 on Rocky9 (RHEL9).

Edit: actually the bug is present in 23.10, but seems to be absent in 24.10.1.