pan/bi: Handle needless conversions in nir_lower_bool_to_bitsize

We can end up with conversion instructions to the same type of integer
with nir_lower_bool_to_bitsize so let's make
bifrost_nir_lower_algebraic_late handle those cases.

Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
Acked-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Eric R. Smith <eric.smith@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36629>

src/panfrost/compiler/bifrost_nir_algebraic.py

@@ -106,6 +106,12 @@ algebraic_late = [
     (('ffract', a), ('fadd', a, ('fneg', ('ffloor', a))), 'gpu_arch >= 11'),
 ]
 
+# nir_lower_bool_to_bitsize can generate needless conversions.
+for bits in [8, 16, 32]:
+    algebraic_late += [
+        ((f'i2i{bits}', f'a@{bits}'), a)
+    ]
+
 # On v11+, ICMP_OR.v4u8 was removed
 for cond in ['ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
     convert_8bit = 'u2u8'