[Bug fortran/91390] treatment of extra parameter in a subroutine call

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91390

Thomas Koenig <tkoenig at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tschwinge at gcc dot gnu.org

--- Comment #4 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
I'm currently working on this... finding a lot of interesting
cases in the test suite, in particular one where I am not sure
what to do.

The test case is gfortran.dg/goacc/acc_on_device-1.f95 , and the code is

! Have to enable optimizations, as otherwise builtins won't be expanded.
! { dg-additional-options "-O -fdump-rtl-expand" }

logical function f ()
  implicit none

  external acc_on_device
  logical (4) acc_on_device

  f = .false.
  f = f .or. acc_on_device ()
  f = f .or. acc_on_device (1, 2)
  f = f .or. acc_on_device (3.14)
  f = f .or. acc_on_device ("hello")

  return
end function f

! Unsuitable to be handled as a builtin, so we're expecting four calls.
! { dg-final { scan-rtl-dump-times "\\\(call \[^\\n\]* acc_on_device" 4
"expand" } }

With my current patch, this would result in

/home/ig25/Gcc/trunk/gcc/testsuite/gfortran.dg/goacc/acc_on_device-1.f95:12:12:

   11 |   f = f .or. acc_on_device ()
      |            2
   12 |   f = f .or. acc_on_device (1, 2)
      |            1
Error: More actual than formal arguments in procedure call at (1) for procedure
defined at (2)
/home/ig25/Gcc/trunk/gcc/testsuite/gfortran.dg/goacc/acc_on_device-1.f95:13:12:

   11 |   f = f .or. acc_on_device ()
      |            2
   12 |   f = f .or. acc_on_device (1, 2)
   13 |   f = f .or. acc_on_device (3.14)
      |            1
Error: More actual than formal arguments in procedure call at (1) for procedure
defined at (2)
/home/ig25/Gcc/trunk/gcc/testsuite/gfortran.dg/goacc/acc_on_device-1.f95:14:12:

   11 |   f = f .or. acc_on_device ()
      |            2
......
   14 |   f = f .or. acc_on_device ("hello")
      |            1
Error: More actual than formal arguments in procedure call at (1) for procedure
defined at (2)

where the warnings could be mitigated to a warning using -std=legacy.

Now, needless to say, this is illegal Fortran. Is the test case actually
a valid use case?  Wouldn't it be better to make this into an intrinsic
with -fopenacc? Would it be acceptable to have to set -std=legacy on that
particular use case?