Perform those before some derefs are gone when we lower the buffers after the st_nir_opts() call.
Intel SKL shader-db results:
total instructions in shared programs: 15593685 -> 15590708 (-0.02%)
instructions in affected programs: 378078 -> 375101 (-0.79%)
helped: 777
HURT: 44
helped stats (abs) min: 1 max: 68 x̄: 4.07 x̃: 4
helped stats (rel) min: 0.04% max: 31.58% x̄: 2.88% x̃: 1.37%
HURT stats (abs) min: 1 max: 24 x̄: 4.20 x̃: 2
HURT stats (rel) min: 0.17% max: 8.00% x̄: 1.60% x̃: 1.27%
95% mean confidence interval for instructions value: -4.02 -3.23
95% mean confidence interval for instructions %-change: -2.93% -2.35%
Instructions are helped.
total loops in shared programs: 4815 -> 4815 (0.00%)
loops in affected programs: 0 -> 0
helped: 0
HURT: 0
total cycles in shared programs: 371965528 -> 371788566 (-0.05%)
cycles in affected programs: 184190307 -> 184013345 (-0.10%)
helped: 3650
HURT: 2855
helped stats (abs) min: 1 max: 59400 x̄: 99.45 x̃: 15
helped stats (rel) min: <.01% max: 43.18% x̄: 2.60% x̃: 1.02%
HURT stats (abs) min: 1 max: 16362 x̄: 65.16 x̃: 10
HURT stats (rel) min: <.01% max: 66.22% x̄: 2.78% x̃: 0.81%
95% mean confidence interval for cycles value: -53.73 -0.68
95% mean confidence interval for cycles %-change: -0.39% -0.08%
Cycles are helped.
total spills in shared programs: 11936 -> 11956 (0.17%)
spills in affected programs: 443 -> 463 (4.51%)
helped: 0
HURT: 8
total fills in shared programs: 25644 -> 25619 (-0.10%)
fills in affected programs: 2306 -> 2281 (-1.08%)
helped: 24
HURT: 2
LOST: 7
GAINED: 16
Total CPU time (seconds): 1679.04 -> 1695.69 (0.99%)