message: Don't recompute "as_dtype" in backprop._ones
diff: @@ -624,13 +624,14 @@ def _zeros(shape, dtype):
  def _ones(shape, dtype):
  - if dtypes.as_dtype(dtype) == dtypes.string:
  + as_dtype = dtypes.as_dtype(dtype)
  + if as_dtype == dtypes.string:
  return None
  if not context.context().executing_eagerly():
  return array_ops.ones(shape, dtype)
  - if dtypes.as_dtype(dtype).is_bool:
  + if as_dtype.is_bool:
  value = True
  else:
  value = 1
  