[Bug fortran/25818] New: Problem with handling optional and entry master arguments

[jakub at gcc dot gnu dot org]

PROGRAM TSBVSL
           CALL NRANIN(54321.)
         END

         SUBROUTINE NRAN(VECTOR,N)
          DIMENSION VECTOR(N)
         DO I=1,N
         VECTOR(I) = RNDM(I)
         END DO
         RETURN
         ENTRY NRANIN (V)
         CALL RDMIN(V)
         RETURN
         END

         SUBROUTINE RDMIN(V)
         END

         REAL FUNCTION RNDM(I)
         RNDM=I
         END

is miscompiled on x86_64-linux at -O and higher.
The problem is that gfc_trans_deferred_vars emits some code e.g. to compute
array argument's ubound and this happens before the entry master switch,
so the the N argument pointer might be NULL.

I think we should:
a) in gfc_sym_type try harder for
   !sym->attr.optional && sym->ns->proc_name->attr.entry_master
   to see whether build_reference_type (type) could be used
   by walking all entries and see if the argument is present in all the entries
   and not optional, then it can be reference_type
b) probably use some flag set for all code emitted before the entry master
switch
   which would cause all parameters to expand to p != NULL ? *p : 0 rather than
   just *p if p is POINTER_TYPE.


-- 
           Summary: Problem with handling optional and entry master
                    arguments
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25818