[Mesa-dev] V7 Loop unrolling in NIR

[Timothy Arceri]

V7:
 - paritally out of ssa in unrolling pass to avoid phis
 - lots of simplification/tidy ups in the analysis pass
 - if_uses bug fix (missing functionality) in lcssa fixed
 - better support for non trivial loop terminators
 - fixed all loop HURT except 1 that is too big to unroll.

total instructions in shared programs: 12584624 -> 12584621 (-0.00%)
instructions in affected programs: 68507 -> 68504 (-0.00%)
helped: 70
HURT: 170

total cycles in shared programs: 241499996 -> 241476226 (-0.01%)
cycles in affected programs: 4060722 -> 4036952 (-0.59%)
helped: 1241
HURT: 1278

total loops in shared programs: 4245 -> 2948 (-30.55%)
loops in affected programs: 1535 -> 238 (-84.50%)
helped: 1142
HURT: 1

LOST:   26
GAINED: 16