> > And sorry that I 'hijacked' this thread - should I open a new ticket?
> 
> I don't think you need to open a bug for it at all. As its not a bug in Mesa
> its a shader bug.
> 

It's not a bug in Mesa but if adopting the same behavior than other drivers is
cheap performance-wise I think we should consider it.

For instance, adding a prolog to PS that always initializes v0, v1, v2 to 0
could do the trick... maybe there are other/better ways though.