Comment # 4 on bug 85696 from David Heidelberg (okias)

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).

Axel had idea we could do something like:

. if wants to use rL to index constant register
. . if a0 is used somewhere in the shader
. . then copy the content to temp. load rL to a0. do the op. restore a0
. . else copy rL to a0 and use it
. else do nothing particular