Altivec + 16 byte alignment

[John David Anglin]

>       /* Ignore alignment we can't do with expected alignment of the
>          boundary.  */
>       if (alignment * BITS_PER_UNIT > PREFERRED_STACK_BOUNDARY)
> 	alignment = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
> 			 
>     but really that's wrong, and at a minimum it should warn the user
>     that their requested alignment isn't going to happen (better would be
>     to just ensure the requested alignment).  We occasionally get bug
>     reports about this, but so far no-one has invested the effort to
>     implement arbitrary stack alignment.
> 
> Now we have *yet another* macro involved in alignment!

Another issue is GCC's alignment attribute is silently ignored for stack
locals and the documentation doesn't say that.

Dave
-- 
J. David Anglin                                  dave.anglin@nrc-cnrc.gc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6605)