[Mesa-dev] killing off the address reg in tgsi

[Roland Scheidegger]

Hi,

the address reg in tgsi is quite a nuisance. glsl-to-tgsi code assumes
that indirections can only be done through the address reg and has quite
some extra code to deal with this. Even though hardware and apis which
worked like that are definitely old by now.
Thus, I'm proposing the address reg be nuked. I am however not quite
sure what the implications for drivers are, other than I'm certain
llvmpipe can handle that already.
For that reason, I suspect at least initially a new cap bit would be
required so glsl-to-tgsi would skip the extra code. I tend to think
longer term it would be great if it could be nuked completely, I am
however not sure if that is easily done with drivers for old hw (such as
r300) - I guess if necessary we could keep operations such as ARL (or
even ARR though clearly not UARL!) and just define them to be usable
with temp regs.

Opinions?

Roland