diff --git a/tinygrad/tensor.py b/tinygrad/tensor.py
index 4430c048b7..f878010e8a 100644
--- a/tinygrad/tensor.py
+++ b/tinygrad/tensor.py
@@ -14,9 +14,10 @@ from tinygrad.ops import LoadOps
 # An instantiation of the Function is the Context
 class Function:
   def __init__(self, device:str, *tensors:Tensor):
-    self.device, self.parents = device, tensors
-    self.needs_input_grad = [t.requires_grad for t in self.parents]
+    self.device = device
+    self.needs_input_grad = [t.requires_grad for t in tensors]
     self.requires_grad = True if any(self.needs_input_grad) else None if None in self.needs_input_grad else False
+    if self.requires_grad: self.parents = tensors
 
   def forward(self, *args, **kwargs): raise NotImplementedError(f"forward not implemented for {type(self)}")
   def backward(self, *args, **kwargs): raise RuntimeError(f"backward not implemented for {type(self)}")
@@ -213,8 +214,8 @@ class Tensor:
     self.grad = Tensor(1, device=self.device, requires_grad=False)
 
     for t0 in reversed(self.deepwalk()):
-      if not any(x.requires_grad for x in t0._ctx.parents):
-        del t0._ctx  # TODO: does it help to delete this here ever?
+      if not t0.requires_grad:
+        del t0._ctx # TODO: does it help to delete this here ever?
         continue
       assert (t0.grad is not None)
       grads = t0._ctx.backward(t0.grad.lazydata)