[Bug][Relay] TVM generates input name that cannot be imported with the parser

[mehrdadh]

I'm compiling an ONNX model which I realized the input name has this format input:0. When I import the model and run it, it works fine, however if I try to import the same Relay text with the parser it will result in error.

cc @gigiblender

[slyubomirsky]

Can you write a simple pass that will change ("sanitize") the variable names? I don't know if a colon is treated in any special way by the parser, but you could try replacing them with underscores. I thought the parser did some sanitization of its own and am surprised that this still happens.