[Bug][Relax][Frontend][ONNX] ConvTranspose with 3D (5D) input fails in from_onnx: NotImplementedError

[siyiweigeHEW]

Expected behavior

A valid ONNX ConvTranspose model with 3D transposed convolution (5D input X: (N, C, D1, D2, D3)) should be imported successfully by tvm.relax.frontend.onnx.from_onnx, just like the 1D and 2D cases. The ONNX spec allows arbitrary N-D transposed convolution, and topi.nn.conv3d_transpose already exists, so the capability is present.

Actual behavior

from_onnx raises NotImplementedError:

NotImplementedError: Relax ConvTranspose3d not supported yet

raised at python/tvm/relax/frontend/onnx/onnx_frontend.py:1352 in ConvTranspose._impl_v1, which only handles ndim == 3 (1D) and ndim == 4 (2D) and hard-codes raise NotImplementedError for ndim == 5.

The same model passes onnx.checker and runs correctly in onnxruntime (output shape (1, 3, 6, 6, 6)), confirming it is a valid, runnable ONNX model.

Environment

• OS: Linux
• TVM: v0.24.dev0 (main branch, commit 262c6d2e0, built 2026-02-11)
• Python: 3.11
• onnx: 1.20.1
• onnxruntime: 1.24.1

Steps to reproduce

"""Repro: 3D ConvTranspose is a valid & runnable ONNX model, but TVM relax frontend rejects it."""
import numpy as np
import onnx, onnxruntime
from onnx import helper, TensorProto
from tvm.relax.frontend.onnx import from_onnx

w = np.zeros((2, 3, 3, 3, 3), dtype="float32")
graph = helper.make_graph(
    [helper.make_node("ConvTranspose", ["X", "W"], ["Y"])], "g",
    [helper.make_tensor_value_info("X", TensorProto.FLOAT, [1, 2, 4, 4, 4])],
    [helper.make_tensor_value_info("Y", TensorProto.FLOAT, [1, 3, 6, 6, 6])],
    [helper.make_tensor("W", TensorProto.FLOAT, [2, 3, 3, 3, 3], w.tolist())],
)
model = helper.make_model(graph, opset_imports=[helper.make_opsetid("", 18)])
model.ir_version = 8
onnx.checker.check_model(model)                                   # (1) valid ONNX model
x = np.random.rand(1, 2, 4, 4, 4).astype("float32")
y = onnxruntime.InferenceSession(model.SerializeToString()).run(None, {"X": x})[0]
print("onnxruntime runs OK ->", y.shape)                          # (2) reference impl works
from_onnx(model, shape_dict={"X": [1, 2, 4, 4, 4]})               # (3) TVM rejects the same model

Actual output:

onnxruntime runs OK -> (1, 3, 6, 6, 6)
Traceback (most recent call last):
  ...
  File "tvm/relax/frontend/onnx/onnx_frontend.py", line 1352, in _impl_v1
    raise NotImplementedError("Relax ConvTranspose3d not supported yet")
NotImplementedError: Relax ConvTranspose3d not supported yet

Triage

• needs-triage
• bug
• relax
• frontend/onnx