aco: 8/16-bit optimizations
shader-db (Navi, fp16 enabled):
Totals from 352 (0.28% of 127638) affected shaders:
VGPRs: 22488 -> 22480 (-0.04%)
CodeSize: 2101632 -> 2095464 (-0.29%)
Instrs: 407558 -> 406733 (-0.20%)
Cycles: 3876404 -> 3866120 (-0.27%)
VMEM: 135459 -> 135515 (+0.04%); split: +0.16%, -0.12%
SMEM: 17329 -> 17328 (-0.01%)
SClause: 15433 -> 15432 (-0.01%)
Copies: 25811 -> 25202 (-2.36%)
Branches: 10483 -> 10441 (-0.40%)
PreVGPRs: 20975 -> 20973 (-0.01%)
I haven't run CTS for this MR yet
I created !5245 (merged) and now this MR is just RA changes