GELU support in XNNPACK

[phoebesv]

We would like to contribute rvv GELU in XNNPACK.
Does the XNNPACK plan to support GELU (related APIs, scalar code and TFLite delegation, etc.) ?
This is required for bert models (e.g. bert_base and bert_large)

[bhbruce]

Hi @fbarchard @Maratyszcza

Do you have any suggestions about this Op?

[ngzhian]

@alankelly i think Marat wanted to support this but was not prioritized. see b/272379108

[alankelly]

GELU is not on our roadmap, however, please feel free to add the required operator & subgraph support & scalar microkernels.

XNNPACK has strict precision requirements, the maximum error of your implementation will have to be found via exhaustive testing.

[phoebesv]

Thank you for your response. We will consider and explore the addition of the required operator, subgraph support, and scalar microkernels for GELU.