altivec.h add parentheses

[Jason Merrill]

>>>>> "Aldy" == Aldy Hernandez <aldyh@redhat.com> writes:

> consider this:
> 	#define foo() (vector int) blah

> 	hotdog = (vector short)foo();

> this gets expanded into:

> hotdog = (__attribute__ ((vector_size(16))) short) (__attribute__ ((vector_size(16))) int) blah;

> both attributes in a row cause parse errors at times.  i'm pretty sure
> this is a parsing bug, i'm too lazy to debug it now.  

If this is with my vector literal patch applied, the Altivec spec gives
its blessing to this particular parsing bug...:)

> for now, i'm adding an extra level of parentheses to all altivec functions
> returning casted values... which can't hurt at all.

I don't know if this would fix the problem, but you should really adjust
the altivec.h macros so that all uses of the macro parameters are wrapped
in parens.

Jason