Add isinstance check before gcd call in SumNode.__lt__ (#2450)

* Add isinstance check before gcd call

* Delete blank lines

* Fix unit test typo

* Delete blank lines again

---------

Co-authored-by: Paul Gustafson <paul.gustafson@theambrusgroup.com>

test/unit/test_symbolic.py

@@ -394,6 +394,14 @@ class TestSymbolicSymbolicOps(unittest.TestCase):
     assert a < 3 and (a < 3).min == 0 and (a < 3).max == 1
     assert a > 3 and (a > 3).min == 0 and (a > 3).max == 1
 
+  def test_sumnode_mulnode_lt(self):
+    a = Variable("a", 1, 2)
+    b = Variable("b", 1, 2)
+    c = Variable("c", 1, 2)
+    x = SumNode([MulNode(a, b), c])
+    assert isinstance((x < 3), Node) and (x < 3) == 0
+    assert isinstance((x < 4), LtNode) and (x < 4).min == 0 and (x < 4).max == 1
+
   def test_num_node_mul_node(self):
     a = Variable("a", 1, 5)
     b = NumNode(2) * a
@@ -448,6 +456,5 @@ class TestSymbolicSymbolicOps(unittest.TestCase):
     c = b.substitute({a: NumNode(1)})
     assert c == NumNode(2)
 
-
 if __name__ == '__main__':
   unittest.main()

tinygrad/shape/symbolic.py

@@ -290,7 +290,7 @@ class SumNode(RedNode):
       if muls:
         # NOTE: gcd in python 3.8 takes exactly 2 args
         mul_gcd = b
-        for x in muls: mul_gcd = gcd(mul_gcd, x.b)  # type: ignore  # mypy cannot tell x.b is int here
+        for x in muls: mul_gcd = gcd(mul_gcd, x.b) if isinstance(x.b, int) else 1
         all_others = Variable.sum(others)
         if all_others.min >= 0 and all_others.max < mul_gcd:
           lhs, b = Variable.sum([mul//mul_gcd for mul in muls]), b//mul_gcd