Update examples/perplexity/perplexity.cpp

Co-authored-by: compilade <git@compilade.net>

Author: jart

examples/perplexity/perplexity.cpp

@@ -639,7 +639,7 @@ static results_perplexity perplexity(llama_context * ctx, const gpt_params & par
         for (int seq = 0; seq < n_seq_batch; seq++) {
             const float * all_logits = num_batches > 1 ? logits.data() : llama_get_logits_ith(ctx, seq*n_ctx + first);
             if (!all_logits) {
-                return 1;
+                return {std::move(tokens), -1, {}, {}};
             }
 
             llama_token * tokens_data = tokens.data() + start + seq*n_ctx + first;