Re: Vector types and type conversions

[Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>]

> The point is that the existing Altivec and SPE cast syntax requires that
>   a C-style cast from one vector type to another be bit-preserving.  So,
> we can't change that (or static_casts, which are the kind of C++ cast
> that are using to implement this kind of C-style cast) without breaking
> backwards compatibility.
I suppose, though, that Chris' proposed array-access extension to vector 
types may make the situation a bit better.  A value preserving cast from 
V4SI to V4SF could be written as:

v4sf fv = { iv[0], iv[1], iv[2], iv[3] };

if the compiler could make sense of it and produce good code -- which is 
probably all but trivial.

Paolo