[Frontend][Tensorflow2] Stridedslice and concat_v2 fix (apache#8483)

* fix for strided_slice when begin > end in case of shrinkaxis_mask

* fix for name_hint missing error for concat_v2 op

* removing a local fix

* adding more testing capability to concat_v2

python/tvm/relay/frontend/tensorflow_ops.py

@@ -1483,7 +1483,13 @@ def _impl(inputs, attr, params, mod):
 def _concatV2():
     def _impl(inputs, attr, params, mod):
         pop_node = inputs.pop(len(inputs) - 1)
-        axis = int(_get_num_param(params, pop_node))
+        try:
+            axis = int(_get_num_param(params, pop_node))
+        except (IndexError, KeyError, AttributeError):
+            try:
+                axis = int(_infer_value(pop_node, params, mod).numpy())
+            except Exception:
+                axis = int(pop_node)
         return AttrCvt(op_name="concatenate", ignores=["T", "N", "Tidx"], extras={"axis": axis})(
             [inputs], attr
         )
@@ -2244,7 +2250,7 @@ def _transform_mask(stride_dim, ellipsis_mask):
                             if begin[index] < 0
                             else begin[index]
                         )
-                        m_end[final_index] = begin[index] + 1
+                        m_end[final_index] = m_begin[final_index] + 1
                         m_stride[final_index] = 1
                         fshape_indices.append(-2)
                     else:

tests/python/frontend/tensorflow/test_forward.py

@@ -2568,7 +2568,9 @@ def test_forward_stridedslice():
 
     _test_stridedslice([], [0], [0], [1], "float32", new_axis_mask=1)
     _test_stridedslice([2], [1], [1], [1], "float32", shrink_axis_mask=1)
+    _test_stridedslice([4], [-1], [0], [1], "float32", shrink_axis_mask=1)
     _test_stridedslice([2, 1], [0], [1], [1], "float32", shrink_axis_mask=1)
+    _test_stridedslice([2, 3, 4], [-2], [0], [1], "float32", shrink_axis_mask=8)
     _test_stridedslice([2, 3, 4], [0], [1], [1], "float32", shrink_axis_mask=8)
     _test_stridedslice([3, 4, 3], [1, -1, 0], [4, -5, 3], [2, -1, 1], "float32")
     _test_stridedslice([3, 4, 3], [1, 0], [4, 3], [2, 1], "float32", ellipsis_mask=8)

tests/python/frontend/tensorflow2/test_functional_models.py

@@ -354,7 +354,8 @@ def get_input(self):
         @tf.function(input_signature=[tf.TensorSpec(shape=(1, 30), dtype=tf.float32)])
         def func(self, x):
             a, b, c = tf.split(x, 3, axis=1)
-            return tf.raw_ops.ConcatV2(values=[a, b, c], axis=1)
+            axis = tf.add(tf.constant(1, dtype="int32"), tf.constant(0, dtype="int32"))
+            return tf.raw_ops.ConcatV2(values=[a, b, c], axis=axis)
 
     run_all(ConcatV2)