nir/opt_algebraic: optimize b2i/b2f comparision with non 0/1 constants

Foz-DB Navi21:
Totals from 28 (0.04% of 79789) affected shaders:
MaxWaves: 732 -> 728 (-0.55%)
Instrs: 23425 -> 22559 (-3.70%)
CodeSize: 137740 -> 132292 (-3.96%)
VGPRs: 1128 -> 1144 (+1.42%)
Latency: 94604 -> 92423 (-2.31%)
InvThroughput: 19166 -> 18814 (-1.84%); split: -2.38%, +0.54%
VClause: 429 -> 423 (-1.40%)
SClause: 937 -> 926 (-1.17%)
Copies: 1199 -> 914 (-23.77%); split: -24.52%, +0.75%
Branches: 451 -> 421 (-6.65%)
PreSGPRs: 1043 -> 996 (-4.51%)
PreVGPRs: 992 -> 973 (-1.92%); split: -3.53%, +1.61%
VALU: 17566 -> 16865 (-3.99%)
SALU: 1254 -> 1157 (-7.74%)
VMEM: 619 -> 609 (-1.62%)

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33761>

src/compiler/nir/nir_opt_algebraic.py

@@ -3268,6 +3268,8 @@ for b2t, xne, xeq, zero, one in (('b2i', 'ine', 'ieq', 0, 1),
         ((xeq, (b2t, 'a@1'), one),  a),
         ((xne, (b2t, 'a@1'), zero), a),
         ((xne, (b2t, 'a@1'), one),  ('inot', a)),
+        ((xeq, (b2t, 'a@1'), '#b'), ('bcsel', (xeq, b, zero), ('inot', a), ('bcsel', (xeq, b, one), a, False))),
+        ((xne, (b2t, 'a@1'), '#b'), ('bcsel', (xeq, b, zero), a, ('bcsel', (xeq, b, one), ('inot', a), True))),
     ]
 
 # This section contains "late" optimizations that should be run before