https://bugs.freedesktop.org/show_bug.cgi?id=85696
--- Comment #5 from Ilia Mirkin imirkin@alum.mit.edu --- (In reply to David Heidelberg (okias) from comment #4)
It's bug in Nine.
Instead of one available ADDR[0], we try use DCL ADDR[0..1].
ADDR[0] is allocated by LOOP (for counter purposes) and then later is allocated ADDR[1].
0 is the address register (already allocated by LOOP, but in this case unused) 1 is UBO index register (misused by location for MOVA (coverted)-> ARR) 2 is sampler index register (not used, correctly).
While the opengl state tracker uses ADDR in this way, it is not in any way required by TGSI or gallium that this be the case. ADDR registers can be used however you want, they're just registers like any other, except that they can be used for indirect indexing into TEMP and CONST registers (perhaps IN and OUT as well, not sure), and with ARB_gs5, into SAMP as well.