I was following the old GH issue / thread related to OpenCL support for 1.x of TensorFlow. I tinkered an got it working with opensource kernel drivers on GCN1 (HD 7970) https://github.com/tensorflow/tensorflow/issues/22

You could do it, and GCN was good at compute (still is with Radeon VI) but I must admit it was far more complicated than any AI researcher would have liked compared to the closed source binary approach of NVidia / Cuda.