remove skipping cast in simplify_valid [pr] (#12472)

* remove skipping cast in simplify_valid [pr]

unsupported statements are handled in uop_given_valid already. the test failed because (100%x) somehow got simplified

* better test

test/unit/test_simplify_valid_idx.py

@@ -104,7 +104,9 @@ class TestValidIdxSimplification(unittest.TestCase):
   def test_simplify_valid_from_div(self):
     x = Variable("x", -100, 100)
     valid = ((x<0)&((100%x).cast(dtypes.bool)))
-    self.assertIsNone(simplify_valid(valid))
+    # NOTE: this simplifies the (100%x) part somehow, still has two clauses
+    self.assertIsNotNone(simplify_valid(valid))
+    self.assertEqual(len(list(valid.split_uop(Ops.AND))), 2)
 
   @unittest.expectedFailure  # TODO: fix
   def test_from_merge_views(self):

tinygrad/uop/symbolic.py

@@ -459,8 +459,6 @@ def simplify_valid(valid:UOp) -> UOp|None:
   something_changed = False
   valids = list(valid.split_uop(Ops.AND))
   for stmt in sorted(valids, key=lambda v: _valid_priority(v, valids)):
-    # TODO: root cause this and test_simplify_valid_from_div
-    if stmt.op is Ops.CAST: return None
     ret.append(newstmt if ret and (newstmt:=uop_given_valid(functools.reduce(operator.and_, ret), stmt)) is not None else stmt)
     if ret[-1] is not stmt: something_changed = True
   return functools.reduce(operator.and_, ret) if something_changed else None