Improve stack layout heuristic.

[Steven Bosscher]

On Sun, Apr 17, 2011 at 9:39 PM, Easwaran Raman <eraman@google.com> wrote:
> @@ -372,8 +366,9 @@
>                 to elements will conflict.  In case of unions we have
>                 to be careful as type based aliasing rules may say
>                 access to the same memory does not conflict.  So play
> -                safe and add a conflict in this case.  */
> -             || contains_union)
> +                safe and add a conflict in this case when -fstrict-aliasing
> +                 is used.  */
> +             || (contains_union && flag_strict_aliasing))
>            add_stack_var_conflict (i, j);
>        }
>     }

Are you sure this change is safe? See http://gcc.gnu.org/PR25654

Ciao!
Steven