[Bug fortran/122206] abstract interface, passing arguments by value to C

[kargls at comcast dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122206

--- Comment #2 from kargls at comcast dot net ---
Code works fine if one does not use an abstract interface and simply uses
an interface statement, i.e.,

  interface
    function simple_function(iarg1, arg2, arg3, arg4) bind(C) result(res)
      import c_double, c_int
      integer(c_int), value, intent(in) :: iarg1
      real(c_double), value, intent(in) :: arg2, arg3, arg4
      real(c_double) :: res
    end function
  end interface 

With the above, -fdump-tree-original produces

  arg3 = 3.0e+0;
  arg4 = 1.000000000000000055511151231257827021181583404541015625e-1;
  iarg1 = 2;
  val1 = simple_function (iarg1, arg2, arg3, arg4);
  val2 = simple_function (iarg1, arg2, arg3, arg4);


With the original code, one sees

  arg3 = 3.0e+0;
  arg4 = 1.000000000000000055511151231257827021181583404541015625e-1;
  iarg1 = 2;
  val1 = simple_function (iarg1, arg2, arg3, arg4);
  val2 = simple_function (&iarg1, &arg2, &arg3, &arg4);