MLBEDSW-2813: Handle non-const weights and check shapes

- Added check for non-constant weights in supported operators
- Added check ifm & ifm2 shapes
- Handle None tensors for CPU operators
- Handle missing attributes for Cast operator

Signed-off-by: Andreas Nevalainen <andreas.nevalainen@arm.com>
Change-Id: I2f16d3d44d0c6da5237550b39273cdb9cc3c7607

1 files changed, 11 insertions, 2 deletions

diff --git a/ethosu/vela/tflite_reader.py b/ethosu/vela/tflite_reader.py
index a2f744d3..7458b907 100644
--- a/ethosu/vela/tflite_reader.py
+++ b/ethosu/vela/tflite_reader.py
@@ -152,7 +152,8 @@ class TFLiteSubgraph:
         activation_function_to_split_out = None
 
         if op_type.startswith("DepthwiseConv2d") or op_type.startswith("Conv2D"):
-            inputs[1] = clone_and_reshape_tensor(inputs[1], (1, 2, 3, 0))
+            if inputs[1].values is not None:
+                inputs[1] = clone_and_reshape_tensor(inputs[1], (1, 2, 3, 0))
             if len(inputs) < 3 or (len(inputs) < 4 and "Backprop" in op_type):
                 # No Bias tensor
                 inputs.append(None)
@@ -160,7 +161,8 @@ class TFLiteSubgraph:
                 inputs[-1] = clone_and_reshape_tensor(inputs[-1], (0,))
 
         if op_type.startswith("FullyConnected"):
-            inputs[1] = clone_and_reshape_tensor(inputs[1], (1, 0))
+            if inputs[1].values is not None:
+                inputs[1] = clone_and_reshape_tensor(inputs[1], (1, 0))
             if len(inputs) < 3:
                 # No Bias tensor
                 inputs.append(None)
@@ -174,6 +176,13 @@ class TFLiteSubgraph:
                 # Reshape should have an attrib "new_shape" but if it is missing, add it based on the output shape
                 op.attrs["new_shape"] = outputs[0].shape
 
+            if op_type == "Cast":
+                # Cast op should have "in/out_data_type" attribs add if missing
+                if "in_data_type" not in op.attrs:
+                    op.attrs["in_data_type"] = inputs[0].dtype
+                if "out_data_type" not in op.attrs:
+                    op.attrs["out_data_type"] = outputs[0].dtype
+
             if "stride_w" in op.attrs:
                 op.attrs["strides"] = (1, op.attrs["stride_h"], op.attrs["stride_w"], 1)
             if "filter_width" in op.attrs: