🐛 Describe the bug

Hit this issue when I was debugging the gemma-3 error in optimum-executorch (CI link).

Upon checking the complained op_overload, the function object is actually a sym_max which is introduced via this line

https://github.com/huggingface/transformers/blob/1d45d90e5d1552eccb6d8cc9b7bba283ccefb808/src/transformers/cache_utils.py#L1725-L1732

        if self.is_sliding[layer_idx]:
            query_length = cache_position.shape[0]
            ...
            local_mask_kv_length = max(query_length, self.sliding_window)
            return local_mask_kv_length, local_mask_kv_offset

in the upstream transformers in the HybridCache class, which is expected as now we set the cache_poistion dim to be dynamic in huggingface/optimum-executorch#73.

The export works fine to have the sym_max in the exported graph (test_hybrid_cache_exportability passed in the transformers), but when further lowering the graph to executorch, the call to_executorch failed.

On chatting with @kimishpatel , it seems like we are missing implementation for sym_max as an op.

Versions

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