This is fine. For Intel hardware, the component mask is actually what we
need and I figured ffs(component_mask) - 1 and bitcount(component_mask)
wasn't all that onerous. I don't care all that much though. Of we're
going this direction, maybe just do size+offset and we can compute the mask
in
Where component_offset here is the offset when accessing components of
a packed variable. Or in other words, location_frac on
nir.h. Different places of mesa use different names for it.
Technically nir_xfb_info consumer can get the same from the
component_mask, it seems somewhat forced to make it
