ir3: fold shared movs into other movs

Handle cases like this in ir3_shared_fold:

cov.f32f16 sssa_1, c0.x
mov.u16u16 ssa_2, sssa_1

=>

cov.f32f16 ssa_1, c0.x

shaderdb results

total instructions in shared programs: 4101548 -> 4101169 (<.01%)
instructions in affected programs: 464035 -> 463656 (-0.08%)
helped: 597
HURT: 220
helped stats (abs) min: 1 max: 290 x̄: 5.75 x̃: 2
helped stats (rel) min: 0.01% max: 46.15% x̄: 5.98% x̃: 1.62%
HURT stats (abs)   min: 1 max: 66 x̄: 13.89 x̃: 7
HURT stats (rel)   min: 0.05% max: 26.19% x̄: 2.44% x̃: 1.27%
95% mean confidence interval for instructions value: -1.79 0.87
95% mean confidence interval for instructions %-change: -4.40% -3.03%
Inconclusive result (value mean confidence interval includes 0).
total nops in shared programs: 796009 -> 797290 (0.16%)
nops in affected programs: 131596 -> 132877 (0.97%)
helped: 262
HURT: 271
helped stats (abs) min: 1 max: 58 x̄: 7.14 x̃: 2
helped stats (rel) min: 0.04% max: 100.00% x̄: 18.44% x̃: 8.82%
HURT stats (abs)   min: 1 max: 42 x̄: 11.63 x̃: 6
HURT stats (rel)   min: 0.08% max: 700.00% x̄: 26.45% x̃: 5.56%
95% mean confidence interval for nops value: 1.18 3.63
95% mean confidence interval for nops %-change: -0.84% 9.61%
Inconclusive result (%-change mean confidence interval includes 0).
total non-nops in shared programs: 3305539 -> 3303879 (-0.05%)
non-nops in affected programs: 291689 -> 290029 (-0.57%)
helped: 692
HURT: 81
helped stats (abs) min: 1 max: 332 x̄: 3.13 x̃: 1
helped stats (rel) min: 0.07% max: 44.44% x̄: 5.13% x̃: 0.85%
HURT stats (abs)   min: 1 max: 64 x̄: 6.25 x̃: 3
HURT stats (rel)   min: 0.08% max: 4.30% x̄: 0.58% x̃: 0.25%
95% mean confidence interval for non-nops value: -3.39 -0.90
95% mean confidence interval for non-nops %-change: -5.23% -3.83%
Non-nops are helped.
total mov in shared programs: 247660 -> 246509 (-0.46%)
mov in affected programs: 28985 -> 27834 (-3.97%)
helped: 693
HURT: 80
helped stats (abs) min: 1 max: 76 x̄: 2.37 x̃: 1
helped stats (rel) min: 0.58% max: 100.00% x̄: 26.02% x̃: 11.11%
HURT stats (abs)   min: 1 max: 60 x̄: 6.17 x̃: 3
HURT stats (rel)   min: 0.60% max: 44.12% x̄: 7.66% x̃: 4.55%
95% mean confidence interval for mov value: -1.93 -1.04
95% mean confidence interval for mov %-change: -24.80% -20.27%
Mov are helped.
total cov in shared programs: 89503 -> 89503 (0.00%)
cov in affected programs: 0 -> 0
helped: 0
HURT: 0
total dwords in shared programs: 8731102 -> 8728514 (-0.03%)
dwords in affected programs: 472796 -> 470208 (-0.55%)
helped: 344
HURT: 105
helped stats (abs) min: 2 max: 416 x̄: 16.54 x̃: 6
helped stats (rel) min: 0.07% max: 46.88% x̄: 6.16% x̃: 2.00%
HURT stats (abs)   min: 2 max: 192 x̄: 29.54 x̃: 30
HURT stats (rel)   min: 0.11% max: 12.50% x̄: 2.24% x̃: 1.15%
95% mean confidence interval for dwords value: -9.31 -2.22
95% mean confidence interval for dwords %-change: -5.12% -3.27%
Dwords are helped.
total last-baryf in shared programs: 119410 -> 119008 (-0.34%)
last-baryf in affected programs: 43637 -> 43235 (-0.92%)
helped: 206
HURT: 76
helped stats (abs) min: 1 max: 72 x̄: 6.91 x̃: 2
helped stats (rel) min: 0.41% max: 64.77% x̄: 5.72% x̃: 2.27%
HURT stats (abs)   min: 1 max: 61 x̄: 13.45 x̃: 7
HURT stats (rel)   min: 0.44% max: 176.92% x̄: 16.24% x̃: 6.97%
95% mean confidence interval for last-baryf value: -3.26 0.41
95% mean confidence interval for last-baryf %-change: -2.05% 2.44%
Inconclusive result (value mean confidence interval includes 0).
total last-helper in shared programs: 1156163 -> 1159618 (0.30%)
last-helper in affected programs: 226148 -> 229603 (1.53%)
helped: 303
HURT: 170
helped stats (abs) min: 1 max: 142 x̄: 6.89 x̃: 1
helped stats (rel) min: 0.07% max: 67.14% x̄: 3.89% x̃: 1.01%
HURT stats (abs)   min: 1 max: 173 x̄: 32.60 x̃: 24
HURT stats (rel)   min: 0.06% max: 266.67% x̄: 18.45% x̃: 2.67%
95% mean confidence interval for last-helper value: 4.46 10.15
95% mean confidence interval for last-helper %-change: 1.98% 6.30%
Last-helper are HURT.
total half in shared programs: 0 -> 0
half in affected programs: 0 -> 0
helped: 0
HURT: 0
total full in shared programs: 261434 -> 261409 (<.01%)
full in affected programs: 192 -> 167 (-13.02%)
helped: 3
HURT: 8
helped stats (abs) min: 11 max: 11 x̄: 11.00 x̃: 11
helped stats (rel) min: 22.92% max: 22.92% x̄: 22.92% x̃: 22.92%
HURT stats (abs)   min: 1 max: 1 x̄: 1.00 x̃: 1
HURT stats (rel)   min: 12.50% max: 25.00% x̄: 18.75% x̃: 18.75%
95% mean confidence interval for full value: -6.04 1.49
95% mean confidence interval for full %-change: -6.22% 20.99%
Inconclusive result (value mean confidence interval includes 0).
total constlen in shared programs: 573812 -> 573812 (0.00%)
constlen in affected programs: 0 -> 0
helped: 0
HURT: 0
total cat0 in shared programs: 888047 -> 889329 (0.14%)
cat0 in affected programs: 145060 -> 146342 (0.88%)
helped: 262
HURT: 271
helped stats (abs) min: 1 max: 58 x̄: 7.13 x̃: 2
helped stats (rel) min: 0.03% max: 77.42% x̄: 16.04% x̃: 8.70%
HURT stats (abs)   min: 1 max: 42 x̄: 11.62 x̃: 6
HURT stats (rel)   min: 0.14% max: 560.00% x̄: 23.51% x̃: 5.26%
95% mean confidence interval for cat0 value: 1.18 3.63
95% mean confidence interval for cat0 %-change: -0.29% 8.43%
Inconclusive result (%-change mean confidence interval includes 0).
total cat1 in shared programs: 338427 -> 336766 (-0.49%)
cat1 in affected programs: 38669 -> 37008 (-4.30%)
helped: 692
HURT: 81
helped stats (abs) min: 1 max: 332 x̄: 3.12 x̃: 1
helped stats (rel) min: 0.42% max: 58.33% x̄: 15.55% x̃: 8.33%
HURT stats (abs)   min: 1 max: 60 x̄: 6.11 x̃: 3
HURT stats (rel)   min: 0.43% max: 38.96% x̄: 6.27% x̃: 3.70%
95% mean confidence interval for cat1 value: -3.39 -0.91
95% mean confidence interval for cat1 %-change: -14.46% -12.07%
Cat1 are helped.
total cat2 in shared programs: 1498022 -> 1498022 (0.00%)
cat2 in affected programs: 0 -> 0
helped: 0
HURT: 0
total cat3 in shared programs: 1193698 -> 1193698 (0.00%)
cat3 in affected programs: 0 -> 0
helped: 0
HURT: 0
total cat4 in shared programs: 84032 -> 84032 (0.00%)
cat4 in affected programs: 0 -> 0
helped: 0
HURT: 0
total cat5 in shared programs: 45976 -> 45976 (0.00%)
cat5 in affected programs: 0 -> 0
helped: 0
HURT: 0
total cat6 in shared programs: 49579 -> 49579 (0.00%)
cat6 in affected programs: 0 -> 0
helped: 0
HURT: 0
total cat7 in shared programs: 3767 -> 3767 (0.00%)
cat7 in affected programs: 0 -> 0
helped: 0
HURT: 0
total stp in shared programs: 2478 -> 2478 (0.00%)
stp in affected programs: 0 -> 0
helped: 0
HURT: 0
total ldp in shared programs: 601 -> 601 (0.00%)
ldp in affected programs: 0 -> 0
helped: 0
HURT: 0
total sstall in shared programs: 359510 -> 354499 (-1.39%)
sstall in affected programs: 75169 -> 70158 (-6.67%)
helped: 366
HURT: 79
helped stats (abs) min: 1 max: 103 x̄: 15.25 x̃: 7
helped stats (rel) min: 0.44% max: 100.00% x̄: 34.04% x̃: 21.26%
HURT stats (abs)   min: 1 max: 44 x̄: 7.22 x̃: 4
HURT stats (rel)   min: 0.00% max: 1550.00% x̄: 70.29% x̃: 16.67%
95% mean confidence interval for sstall value: -13.50 -9.02
95% mean confidence interval for sstall %-change: -24.40% -6.63%
Sstall are helped.
total (ss) in shared programs: 92229 -> 90970 (-1.37%)
(ss) in affected programs: 16747 -> 15488 (-7.52%)
helped: 418
HURT: 59
helped stats (abs) min: 1 max: 26 x̄: 3.22 x̃: 1
helped stats (rel) min: 0.15% max: 100.00% x̄: 45.32% x̃: 20.69%
HURT stats (abs)   min: 1 max: 4 x̄: 1.51 x̃: 1
HURT stats (rel)   min: 5.88% max: 100.00% x̄: 21.95% x̃: 18.18%
95% mean confidence interval for (ss) value: -3.13 -2.14
95% mean confidence interval for (ss) %-change: -41.09% -32.90%
(ss) are helped.
total systall in shared programs: 650986 -> 650994 (<.01%)
systall in affected programs: 42219 -> 42227 (0.02%)
helped: 120
HURT: 199
helped stats (abs) min: 1 max: 569 x̄: 20.64 x̃: 6
helped stats (rel) min: 0.24% max: 100.00% x̄: 26.84% x̃: 16.67%
HURT stats (abs)   min: 1 max: 47 x̄: 12.49 x̃: 6
HURT stats (rel)   min: 0.00% max: 2050.00% x̄: 115.15% x̃: 7.14%
95% mean confidence interval for systall value: -5.35 5.40
95% mean confidence interval for systall %-change: 28.15% 95.33%
Inconclusive result (value mean confidence interval includes 0).
total (sy) in shared programs: 35895 -> 35884 (-0.03%)
(sy) in affected programs: 1206 -> 1195 (-0.91%)
helped: 47
HURT: 47
helped stats (abs) min: 1 max: 5 x̄: 1.38 x̃: 1
helped stats (rel) min: 2.70% max: 50.00% x̄: 16.14% x̃: 20.00%
HURT stats (abs)   min: 1 max: 2 x̄: 1.15 x̃: 1
HURT stats (rel)   min: 3.70% max: 66.67% x̄: 26.57% x̃: 25.00%
95% mean confidence interval for (sy) value: -0.41 0.18
95% mean confidence interval for (sy) %-change: -0.26% 10.69%
Inconclusive result (value mean confidence interval includes 0).
total waves in shared programs: 628660 -> 628652 (<.01%)
waves in affected programs: 48 -> 40 (-16.67%)
helped: 0
HURT: 4
HURT stats (abs)   min: 2 max: 2 x̄: 2.00 x̃: 2
HURT stats (rel)   min: 16.67% max: 16.67% x̄: 16.67% x̃: 16.67%
95% mean confidence interval for waves value: -2.00 -2.00
95% mean confidence interval for waves %-change: -16.67% -16.67%
Waves are HURT.
total loops in shared programs: 1025 -> 1025 (0.00%)
loops in affected programs: 0 -> 0
helped: 0
HURT: 0