[Fix][Relax][ONNX] Fix Range dtype for PrimExpr bounds

[viiccwen]

The ONNX Range importer uses the dtype of the start value as the output dtype for relax.op.arange. The frontend previously passed start.ty.dtype, which is a PrimType wrapper rather than the underlying DataType expected by arange.

This patch passes the underlying dtype with start.ty.dtype.dtype.

The regression test covers a shape-derived bound produced by Shape -> Gather -> Range, and checks that the imported Relax IR contains R.arange(..., dtype="int64").

Verification:

• python -m pytest tests/python/relax/test_frontend_onnx.py::test_range_with_primexpr_limit -q
• pre-commit run --files python/tvm/relax/frontend/onnx/onnx_frontend.py tests/python/relax/test_frontend_onnx.py

Fixes #19999.

[gemini-code-assist]

Code Review

This pull request updates the ONNX frontend in TVM Relax to correctly extract the data type when handling the Range operator, changing start.ty.dtype to start.ty.dtype.dtype. It also adds a new unit test, test_range_with_primexpr_limit, to verify the behavior of the Range operator when the limit is a PrimExpr. There are no review comments, so I have no feedback to provide.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[viiccwen]

Looks like something wrong with Ruff, I add a small lint cleanup to fix it. 🤔

[viiccwen]

cc @tlopex, @guan404ming. ✨🙌