[Relax][ONNX] Support AffineGrid align_corners false

[THINKER-ONLY]

Motivation

ONNX AffineGrid has an align_corners attribute, and the ONNX default is
align_corners=0. The Relax ONNX frontend previously rejected that default with
NotImplementedError, so an ONNX model that omitted the attribute could not be
imported.

Fixes #19690.

Changes

This PR threads align_corners through Relax image.affine_grid, legalization,
and the TOPI implementation. The Relax API keeps the existing
align_corners=True default to preserve current behavior, while the ONNX
frontend reads the ONNX attribute and uses ONNX's default value of 0.

The tests cover Relax struct-info inference, legalization, numerical execution,
and ONNX import/execution for both align_corners=0 and align_corners=1.

Testing

• cmake --build build --parallel $(nproc)
• pre-commit run --files include/tvm/relax/attrs/image.h python/tvm/relax/frontend/onnx/ onnx_frontend.py python/tvm/relax/op/image/image.py python/tvm/relax/op/op_attrs.py python/ tvm/relax/transform/legalize_ops/image.py python/tvm/topi/image/grid_sample.py python/tvm/ topi/testing/grid_sample_python.py src/relax/op/image/resize.cc src/relax/op/image/resize.h tests/python/relax/test_frontend_onnx.py tests/python/relax/test_op_image.py tests/python/ relax/test_transform_legalize_ops_image.py
• pytest tests/python/relax/test_op_image.py tests/python/relax/ test_transform_legalize_ops_image.py -q
• pytest tests/python/relax/test_frontend_onnx.py -k 'affine_grid or grid_sample' -q

[gemini-code-assist]

Code Review

This pull request adds support for the align_corners attribute in the affine_grid operator across TVM Relax, TOPI, and the ONNX frontend, including corresponding tests. The review feedback highlights critical backward-compatibility issues with older IR/models where affine_grid may not have attributes. Specifically, strictly requiring attrs to be non-null in C++ struct info inference and directly accessing call.attrs.align_corners in Python legalization without checking if call.attrs is None can lead to failures.

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[gemini-code-assist]

To maintain backward compatibility with older IR/models where affine_grid did not have attributes, we should not strictly require attrs to be non-null. Since attrs is not used anywhere else in InferStructInfoAffineGrid, we can safely remove these lines.

[gemini-code-assist]

If call.attrs is None (which is the case for older IR/models where affine_grid had no attributes), accessing call.attrs.align_corners will raise an AttributeError. To prevent this and ensure backward compatibility, we should default align_corners to True if call.attrs is None.

Suggested change

	align_corners=call.attrs.align_corners,
	align_corners=call.attrs.align_corners if call.attrs else True,

[Copilot]

Pull request overview

Adds support for ONNX AffineGrid’s default align_corners=0 behavior in the Relax ONNX frontend by plumbing an align_corners attribute through the Relax image.affine_grid op, legalization, and TOPI implementation, while preserving existing Relax default behavior (align_corners=True).

Changes:

• Introduce AffineGridAttrs(align_corners) for relax.image.affine_grid and thread it through Relax op construction and legalization.
• Extend TOPI affine_grid (and its Python reference) to generate grids for both align_corners=True/False.
• Update ONNX AffineGrid import to honor ONNX’s align_corners attribute default (0), and add tests for both alignment modes.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
include/tvm/relax/attrs/image.h	Adds AffineGridAttrs with align_corners and reflection metadata.
src/relax/op/image/resize.h	Updates C++ Relax op constructor signature to accept align_corners.
src/relax/op/image/resize.cc	Registers AffineGridAttrs, attaches attrs to calls, and updates op registration to use attrs type.
python/tvm/relax/op/op_attrs.py	Registers Python-side AffineGridAttrs object wrapper.
python/tvm/relax/op/image/image.py	Extends Relax Python API for affine_grid(..., align_corners=...) (default True).
python/tvm/relax/transform/legalize_ops/image.py	Passes align_corners through legalization to TOPI.
python/tvm/topi/image/grid_sample.py	Extends TOPI affine_grid to support both align_corners modes.
python/tvm/topi/testing/grid_sample_python.py	Extends NumPy reference affine_grid_python for both align_corners modes.
python/tvm/relax/frontend/onnx/onnx_frontend.py	Uses ONNX align_corners attribute (default 0) and forwards it into Relax affine_grid.
tests/python/relax/test_op_image.py	Adds attribute test + struct-info inference coverage + E2E numeric coverage for both alignments.
tests/python/relax/test_transform_legalize_ops_image.py	Adds legalization test coverage for align_corners=False expected TIR.
tests/python/relax/test_frontend_onnx.py	Parameterizes ONNX AffineGrid test to cover omitted attr (default), 0, and 1.

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