More div conditions (#10432)

* add condition

* add test

* use Variable

test/unit/test_uop_symbolic.py

@@ -857,5 +857,16 @@ class TestBounds(unittest.TestCase):
     assert ((alu0+2559)//-4).vmin == -639 and ((alu0+2559)//-4).vmax == 0
     assert (((alu0+2559)//-4)*(-1)).vmin == 0 and (((alu0+2559)//-4)*(-1)).vmax == 639
 
+class TestFuzzFailure(unittest.TestCase):
+  def test_fuzz_failure1(self):
+    v1=Variable('v1', 0, 8)
+    v2=Variable('v2', 0, 2)
+    v3=Variable('v3', 0, 1)
+    expr = (((((((((((((((((((((((0//4)%2)//8)+-2)+-4)+-3)+v1)+-4)+v2)+-2)+v3)+v2)//3)%7)*1)//2)+v2)*-1)+2)+1)+0)+-3)+v3)
+    v1_val, v2_val, v3_val = v1.const_like(8), v2.const_like(0), v3.const_like(0)
+    num = expr.simplify().substitute({v1:v1_val, v2:v2_val, v3:v3_val}).ssimplify()
+    rn = expr.substitute({v1:v1_val, v2:v2_val, v3:v3_val}).ssimplify()
+    assert num==rn, f"{num} != {rn}"
+
 if __name__ == '__main__':
   unittest.main()

tinygrad/codegen/symbolic.py

@@ -282,7 +282,7 @@ symbolic = symbolic_simple+commutative+PatternMatcher([
   # ** div **
   # div folding
   ((UPat.var("x")//UPat.cvar("c") + UPat.cvar("a"))//UPat.cvar("d"), lambda x,c,a,d: (x+a*c)//(c*d)
-      if x.vmin>=0 or x.vmax<=0 else None),  # (x//c+a)//d -> (x+a*c)//(c*d)
+    if (x.vmin>=0 and a.vmin>=0) or (x.vmax<=0 and a.vmax<=0) else None),  # (x//c+a)//d -> (x+a*c)//(c*d)
   (UPat.var("x", dtypes.sints) // UPat.var("y"), lambda x,y: div_and_mod_folding(x,y,Ops.IDIV)),
   (UPat.var("x") // UPat.var("d"), lambda x,d: -(x//(-d)) if d.vmax <=0 else None),
   (UPat.var("x") // UPat.var("d"), lambda x,d: -((-x)//d) if x.vmax <=0 else None),