[Relay] avoid using relay module

Author: kaitingwang

python/tvm/relay/op/_tensor_grad.py

@@ -22,7 +22,6 @@
 from .transform import collapse_sum_like, broadcast_to_like, where
 from .tensor import exp, negative, power, less
 from .tensor import zeros_like, ones_like
-from tvm import relay
 
 @register_gradient("log")
 def log_grad(orig, grad):
@@ -124,11 +123,9 @@ def clip_grad(orig, grad):
     """Returns grad * (select(x < min || max < x , 0, 1))."""
     x = orig.args[0]
     a_min = orig.attrs.get_int("a_min")
-    a_min_const = relay.const(a_min)
     a_max = orig.attrs.get_int("a_max")
-    a_max_const = relay.const(a_max)
-    a_mins = relay.full_like(x, a_min_const)
-    a_maxs = relay.full_like(x, a_max_const)
+    a_mins = broadcast_to_like(const(a_min), x)
+    a_maxs = broadcast_to_like(const(a_max), x)
     zeros = zeros_like(x)
     ones = ones_like(x)
     return [where(less(x, a_mins), zeros, where(less(a_maxs, x), zeros, ones * grad))]