It turned out that the front-end wasn't fully using the information about the 
null exclusion either in some cases.  This eliminates redundant access checks 
in the callee for subprograms with IN or IN/OUT parameters of an null-exclusion 
access subtype, which were introduced in Ada 2005.  The compiler already omits 
these checks in the case of non-null access parameters present in Ada 95.  An 
access check is generated in the caller in both cases.

The compiler must generate no access checks within P2 for the following unit:

package Pkg is

   type Varray is array (Integer range <>) of Long_Float;

   type Ptr is access Varray;

   procedure P1 (X : not null access Varray);

   procedure P2 (X : not null Ptr);

end Pkg;

package body Pkg is

   procedure P1 (X : not null access Varray) is
   begin
     for I in X'Range loop
       X (I) := 0.0;
     end loop;
   end;

   procedure P2 (X : not null Ptr) is
   begin
     for I in X'Range loop
       X (I) := 0.0;
     end loop;
   end;

end Pkg;


2011-09-26  Eric Botcazou  <ebotcazou@adacore.com>
            Robert Dewar  <dewar@adacore.com>

	* sem_ch6.adb (Set_Formal_Mode): Set Can_Never_Be_Null on an IN or IN
	OUT formal parameter which is of an null-exclusion access subtype.


-- 
Eric Botcazou