[Bug testsuite/95546] Random Fortran test failures

[sgk at troutmask dot apl.washington.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

--- Comment #5 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Fri, Jun 05, 2020 at 03:46:18PM +0000, jvdelisle at charter dot net wrote:
> 
> I am curious, did this just start happening or is it a long time issue just
> reported.  Locking mecahnisms were adjusted recently I believe.
> 

What locking are you referring to?  If it some recent changes
to libgfortran's pthread locking, then I think that has nothing
to do with the problem reported here.

The code eof_4.f90 runs multiple tests.  The looks like

  open(unit=99, file='test.dat', status='new')
  !
  ! Test 1
  !
  close(99, status='delete')

  open(unit=99, file='test.dat', status='new')
  !
  ! Test 2
  !
  close(99, status='delete')

  open(unit=99, file='test.dat', status='new')
  !
  ! Test 3
  !
  close(99, status='delete')

The above is actually testing Fortran feature.

HJ Lu reported problems with 'make -jN', which suggests that
eof_4.f90 is being compiled and executed in parallel.  That
is subject to races.  Dejagnu needs to be told that eof_4.f90
cannot be run in parallel.  If it is not possible to defeat
dejagnu, then the test will need to changed to use a unique
file name

  character(len=20) name  
  write(name, '(A,I0,A)') 'tmp', getpid(), '.dat'

  open(unit=99, file=name, status='new')
  !
  ! Test 1
  !
  close(99, status='delete')

The test could also be adjusted to use inquire() and sleep()
(need to check syntax)

1 inquire(file='test.dat', exists=stat)
  if (stat == 1) then
     call sleep(2)
     goto 1
  end if