[PATCH] Create vector types on demand and deprecate __attribute__ ((mode(Vxxyy)))

[Paolo Bonzini]

> This is a mistake.  We're looking to get rid of some of the vector
> modes, remember?

We will, but we still have them...

> I think a better definition of vector type
> compatibility is if the width is the same and the underlying types
> are compatible.

... that was going to be in a follow-up patch that implemented the second part
of your plan.  I will try to work on it after tree-ssa is merged, because I'd
like to use the same approach that is used to lower complex types (if I
understood correctly).

> I don't suppose these get hashed anywhere?  Given how __vector_size__
> gets used by Altivec, I'd hate to be creating new type nodes every
> time the attribute is mentioned.

Are you really going to create more than 40-50 such types?  I can add back
some kind of hashing later if you want.

Paolo