reshape corner cases for mask rcnn (#19875)

python/mxnet/contrib/onnx/mx2onnx/_op_translations.py

@@ -1682,6 +1682,30 @@ def convert_reshape(node, **kwargs):
         ]
         return nodes
 
+    if targ_shape == [-4, 1, -1, 0, 0, 0] and reverse != 'True':
+        create_tensor([1], name+'_1', kwargs['initializer'])
+        create_tensor([-1], name+'_m1', kwargs['initializer'])
+        nodes = [
+            make_node('Shape', [input_nodes[0]], [name+'_shape']),
+            make_node('Split', [name+'_shape'], [name+'_dim0', name+'_dim1', name+'_dim2',
+                                                 name+'_dim3'], axis=0),
+            make_node('Concat', [name+'_1', name+'_m1', name+'_dim1', name+'_dim2', name+'_dim3'],
+                      [name+'_shape_new'], axis=0),
+            make_node('Reshape', [input_nodes[0], name+'_shape_new'], [name], name=name)
+        ]
+        return nodes
+
+    if targ_shape == [-4, 1, 1000, 0, 0] and reverse != 'True':
+        create_tensor([1], name+'_1', kwargs['initializer'])
+        create_tensor([1000], name+'_1000', kwargs['initializer'])
+        nodes = [
+            make_node('Shape', [input_nodes[0]], [name+'_shape']),
+            make_node('Split', [name+'_shape'], [name+'_dim0', name+'_dim1', name+'_dim2'], axis=0),
+            make_node('Concat', [name+'_1', name+'_1000', name+'_dim1', name+'_dim2'],
+                      [name+'_shape_new'], axis=0),
+            make_node('Reshape', [input_nodes[0], name+'_shape_new'], [name], name=name)
+        ]
+        return nodes
 
     not_supported_shape = [-2, -3, -4]
     for val in targ_shape:

tests/python-pytest/onnx/test_operators.py

@@ -249,6 +249,14 @@ def test_onnx_export_reshape_special_cases(tmp_path, dtype):
     M7 = def_model('reshape', shape=(0, 0, -4, 2, 2, 0, 0))
     op_export_test('reshape_spec_7', M7, [x5], tmp_path)
 
+    x6 = mx.nd.ones((8, 7, 6, 5), dtype=dtype)
+    M8 = def_model('reshape', shape=(-4, 1, -1, 0, 0, 0))
+    op_export_test('reshape_spec_8', M8, [x6], tmp_path)
+
+    x7 = mx.nd.ones((1000, 2, 3), dtype=dtype)
+    M9 = def_model('reshape', shape=(-4, 1, 1000, 0, 0))
+    op_export_test('reshape_spec_9', M9, [x7], tmp_path)
+
 
 @pytest.mark.parametrize('dtype', ['int32', 'int64'])
 def test_onnx_export_embedding(tmp_path, dtype):