[PATCH] Improve alias information for arrays

[Eric Botcazou]

> Sort of, I have reduced the failure to
>
> procedure CA11C01 is
>
>    subtype Data_String is String (1 .. 7);
>    type Data_Base_Type is array  (1 .. 1) of Data_String;
>
>    Zoo_Data_Base : Data_Base_Type;
>
> begin
>
>    declare
>
>      -- Remove the routine and the test passes
>      procedure Enter_Animal_Data (I : Integer) is
>      begin
>        Zoo_Data_Base (I) := "Animal ";
>      end Enter_Animal_Data;
>
>    begin
>       Zoo_Data_Base (1) := "Animal ";
>
>       if  Zoo_Data_Base(1)(1 .. 6) /= "Animal"
>         then
>            raise Program_Error;
>       end if;
>    end;
>
> end CA11C01;
>
>
> where we miss a VUSE of the Zoo_Data_Base on the memcmp generated,
> so we dce the initialization.

It looks like quite the same problem as the original one: Zoo_Data_Base is put 
in the FRAME object which is not flagged as call-clobbered because 
ARRAY_RANGE_REF is mis-handled by the aliasing code.

-- 
Eric Botcazou