[Bug] arguments of clip drop after fusion

[soodoshll]

This snippet gives the wrong result

import hidet
import numpy as np
import onnx

from onnx import numpy_helper, TensorProto
from onnx.helper import (
    make_model, make_node, make_graph,
    make_tensor_value_info)

X = make_tensor_value_info('X', TensorProto.FLOAT, [None, None])
Y = make_tensor_value_info('Y', TensorProto.FLOAT, [None, None])

v_min = numpy_helper.from_array(np.array(-1, dtype='float32'), name='v_min')
v_max = numpy_helper.from_array(np.array(1, dtype='float32'), name='v_max')

vmin = make_node('Constant', [], ['vmin'], value=v_min) 
vmax = make_node('Constant', [], ['vmax'], value=v_max) 

node = make_node('Clip',['X', 'vmin', 'vmax'], ['Y'])
graph = make_graph([vmin, vmax, node], 'foo', [X], [Y]) 
onnx_model = make_model(graph)

hidet.option.search_space(1)
hidet_onnx_module = hidet.graph.frontend.from_onnx(onnx_model)
hidet_onnx_module = hidet_onnx_module.to_cuda()

input_names = hidet_onnx_module.input_names

inputs = [hidet.asarray(np.array([6], dtype='float32'), device='cuda')]
symbol_data = [hidet.symbol_like(inputs[0])]
symbol_output = hidet_onnx_module(*symbol_data)
graph: hidet.FlowGraph = hidet.trace_from(symbol_output, inputs=symbol_data)
with hidet.graph.PassContext() as ctx:
    graph_opt: hidet.FlowGraph = hidet.graph.optimize(graph)
    print(graph_opt)
cuda_graph = graph_opt.cuda_graph()
outputs = cuda_graph.run(inputs)

print(outputs[0].detach().cpu().numpy())

It returns 6 instead of 1. The cuda code generated for clip op is just copying the input tensor without any condition statements. vmin and vmax seem to be dropped. Work well when fuse_operator_pass is disabled.

[yaoyaoding]

Thanks @soodoshll.