openvinotoolkit/openvino/add-core-op

When This Skill Applies

Use this skill when:

• A new core operator is needed in OpenVINO.
• Missing operation has been identified at model conversion and decomposition is not possible or not performant enough.
• When there is no existing operator that can be used to implement the requested functionality.

Typical Workflow for Adding Support for a New Op

1. Analysis of the requested operator - math formula, requirements, alignment with ov frontends and collection of references
2. Update of needed files
3. Create tests
4. Create specification describing new op

For more details about executing each step, refer to the sections below.

Skill Instructions

Adding a New Operator to OpenVINO

Create Header and Source Files

The implementation of a class representing an operator must have corresponding .hpp and .cpp files. These files should be created in the following locations:

• **/openvino/src/core/include/openvino/op/new_op_name.hpp
• **/openvino/src/core/src/op/new_op_name.cpp

Define the Operator Class

Create a new operator class that is part of OPENVINO_API and inherits from the Op class:

class OPENVINO_API OpName : public Op {
};

Register the Operator

In the created .hpp file, add the following macro adjusted for new op name and opset number:

OPENVINO_OP("OpName", "opsetX")

Implement Constructors

Implement constructor(s) that take inputs and attributes as arguments.

• An input represents a tensor of data or the output of another operator (Output<Node>).
• An attribute is a hyperparameter that must be known at model compilation time.

Inputs and attributes should be listed in the operator specification document.

Implement validate_and_infer_types

Implement the validate_and_infer_types method. This method is responsible for:

• Validating input shapes and types, if restrictions exist
• Setting the output shapes and element types (precision)

At this stage, input values are usually unknown unless the input is a Constant. If an input is a Constant or can be evaluated, its value may be retrieved. For example, the axis input for a Reduce operator is typically provided as a Constant, allowing its value to be validated and used for output shape inference. Input and output shapes may be static or dynamic. The PartialShape class is used to represent both cases.

Shape Inference

For operators without existing common shape inference function, the shape-related logic should be implemented in a separate shape_infer function so it can be shared with plugins. This function should be added to: **/openvino/src/core/shape_inference/include/ Following the file name convention, example:

• **/openvino/src/core/shape_inference/include/new_op_shape_inference.hpp

Implement visit_attributes

Implement the visit_attributes method, which is used, for example, by the serialization mechanism. Each attribute (usually also a class member) must be visited by calling on_attribute with the attribute name and value, for example:

visitor.on_attribute("axis", m_axis);

Implement clone_with_new_inputs

Implement the clone_with_new_inputs method. This method should return a clone of the operator that:

• Uses the new inputs provided in the input vector
• Preserves the existing attribute values

Conditional Compilation Support

To support conditional compilation, add the following macro at the beginning of every method of the new operator class in the .cpp file:

OV_OP_SCOPE(<operator_version>_<operator_name>_<method_name>);

High-level rules:

• Register the op only in the latest opset
• Use the latest opset number version for new ops namespace.
• Do not edit older opsetX_tbl.hpp files or change existing registrations.
• Don't break compatibility of existing ops

Files to create/update

Note: Treat it as a double-check; no need to create a file if adding a new version of the op.

Create:

• **/openvino/src/core/include/openvino/op/new_op_name.hpp – class declaration.
• **/openvino/src/core/src/op/new_op_name.cpp – implementation.
• **/openvino/src/core/reference/include/openvino/reference/new_op_name.hpp – reference kernel.

Update :

• **/openvino/src/core/dev_api/openvino/op/ops_decl.hpp – register new Op class
• **/openvino/src/core/include/openvino/op/ops.hpp – include new op header
• **/openvino/src/core/include/openvino/opsets/opsetX_tbl.hpp- register new Op class

Core Op Class Pattern

Note: Treat it as example, prefer alignment with the code base (see existing ops for style alignment).

Header (`<op_name>.hpp`):

• Namespace: ov::op::vX (use the latest opset version number for X).
• Base: use an existing utility base when possible, e.g., util::UnaryElementwiseArithmetic for unary elementwise ops.
• Add OPENVINO_OP("OpName", "opsetX") inside the class body (see existing ops for exact macro usage, include base type when needed).
• Declare:
• Default constructor.
• Constructor from const Output<Node>& (and additional inputs/attributes as needed).
• clone_with_new_inputs, evaluate, has_evaluate.

Source (`<op_name>.cpp`):

• Include openvino/op/<op_name>.hpp, element_visitor.hpp, itt.hpp, and the reference header if one exists.
• Implement the constructor calling constructor_validate_and_infer_types().
• Implement clone_with_new_inputs using check_new_args_count and std::make_shared<OpName>.
• Implement evaluate via IF_TYPE_OF_CONVERT_TENSORS that calls ov::reference::<op_name>.
• Implement has_evaluate to return true for supported element types.
• Add OV_OP_SCOPE(v<X>_<OpName>_<method>) at the start of each method (constructor body, clone, evaluate, has_evaluate).

Tests

Ensure all relevant tests are added or updated for the new op:

• for op class/validate_and_infer_types: **/openvino/src/core/tests/type_prop
• for visit_attributes: **/openvino/src/core/tests/visitors/op
• update of ops number in: **/openvino/src/core/tests/opset.cpp
• conformance tests: **/openvino/src/tests/functional/plugin/conformance/test_runner/op_conformance_runner/src/op_impl_check/single_op_graph.cpp
• functional op_reference tests: **/openvino/src/plugins/template/tests/functional/op_reference/

Adding Specification

For the newly added operation, a specification must be created as a .rst file following the conventions for other operators. Example: **/openvino/docs/articles_en/documentation/openvino-ir-format/operation-sets/operation-specs/signals/istft-16.rst