Altivec + 16 byte alignment

[Neil Booth]

Geoff Keating wrote:-

> At present, there's this code in assign_stack_local:
> 
>   /* 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.

Isn't an even better place to do it in the front end, just after parsing
the alignment request?

Neil.