[Bug fortran/67614] ICE on using arithmetic if with null

[gerhard.steinmetz.fort...@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614

--- Comment #5 from Gerhard Steinmetz <gerhard.steinmetz.fort...@t-online.de> 
---
For comparison, a logical if (assumes scalar-logical-expr
instead of scalar-numeric-expr in arithmetic if) "avoids"
an ICE. Analogous examples :


$ cat y1.f90
program p
   logical, allocatable :: z
   if ( null(z) ) print *, 'a'
end


$ cat y2.f90
program p
   logical, pointer :: z
   if ( null(z) ) print *, 'a'
end


$ cat y7.f90
program p
   logical, allocatable :: z
   if ( null(z) ) then
      print *, 'a'
   else
      print *, 'not a'
   end if
end

$ gfortran -g -O0 -Wall -fcheck=all -fno-frontend-optimize y7.f90
$ a.out
 not a