-fno-automatic option (PR 20592)

[FX Coudert]

> How does this patch interact with ALLOCATABLE variables. Are they deallocated 
> at the end of the procedure or not? This needs testing and documenting.

Let's take a simple program:

       integer,allocatable,dimension(:) :: x
       allocate (x(1))
       x = 1
       end

With -fautomatic (default), the variable is deallocated at the end 
(there's a call to _gfortran_deallocate in the tree dump).

With -fno-automatic, the variable is not deallocated. But I think this 
is exactly what it is supposed to do, since it is the behaviour of the 
following program:

       integer,allocatable,dimension(:) :: x
       save
       allocate (x(1))
       x = 1
       end

FX