Fortran + OpenMP code with a subroutine stops abruptly - fortran

Question

I have a piece of experimental code that works perfectly with serial compilation and execution. When I compile it with openmp option on ifort (on ubuntu), the compilation goes on fine but the execution stops abruptly. The code is as follows:
!!!!!!!! module
module array
implicit none
real(kind=8),allocatable :: y(:)
end module array
module nonarray
implicit none
real(kind=8):: aa
end module nonarray
use nonarray; use array
implicit none
integer(kind=8):: iter,i
integer(kind=8),parameter:: id=1
real(kind=8),allocatable:: yt(:)
allocate(y(id)); allocate(yt(id)); y=0.d0; yt=0.d0
aa=4.d0 !!A SYSTEM PARAMETER
!$OMP PARALLEL PRIVATE(y,yt,iter,i)
!$OMP DO
loop1: do iter=1,20 !! THE INITIAL CONDITION LOOP
call random_number(y)!! RANDOM INITIALIZATION OF THE VARIABLE
loop2: do i=1,10000 !! ITERATION OF THE SYSTEM
call evolve(yt)
y=yt
enddo loop2 !! END OF SYSTEM ITERATION
write(1,*)aa,yt
enddo loop1 !!INITIAL CONDITION ITERATION DONE
!$OMP ENDDO
!$OMP END PARALLEL
stop
end
recursive subroutine evolve(yevl)
use nonarray; use array
implicit none
integer(kind=8),parameter:: id=1
real(kind=8):: xf
real(kind=8),intent(out):: yevl(id)
xf=aa*y(1)*(1.d0-y(1))
yevl(1)=xf
end subroutine evolve
For compilation I use the following command:
ifort -openmp -fpp test.f90.
test.f90 being the name of the program.
Any suggestions or help is highly appreciated.

Answer 1

I am not an OMP expert, but I think if the subroutine evolve should see a different (private) y in each thread, you should pass it directly from within the parallelized code block to the subroutine instead of importing it from an external module:
module common
use iso_fortran_env
implicit none
integer, parameter :: dp = real64
real(dp) :: aa
contains
subroutine evolve(y, yevl)
implicit none
real(dp), intent(in) :: y(:)
real(dp), intent(out):: yevl(:)
yevl(1) = aa * y(1) * (1.0_dp - y(1))
end subroutine evolve
end module common
program test
use common
implicit none
integer :: iter, i
real(dp), allocatable :: yt(:), y(:)
allocate(yt(1), y(1))
y(:) = 0.0_dp
yt(:) = 0.0_dp
aa = 4.0_dp
!$OMP PARALLEL DO PRIVATE(y,yt,iter,i)
loop1: do iter = 1, 20
call random_number(y)
loop2: do i = 1, 10000
call evolve(y, yt)
y = yt
end do loop2
write(*,*) aa, yt
end do loop1
!$OMP END PARALLEL DO
end program test
Just an additional warning: the code above worked with various compilers (nagfor 5.3.1, gfortran 4.6.3, ifort 13.0.1), but not with ifort 12.1.6. So, although I can't see any obvious problems with it, I may have messed up something.