From fa96a3e8f24934cbe640c5ab78138486d2e2dbf5 Mon Sep 17 00:00:00 2001
From: Adrian Lundell <adrian.lundell@arm.com>
Date: Fri, 6 Oct 2023 09:32:48 +0200
Subject: [PATCH] Use fallback reference for 8-bit fully connnected operators
 with non-zero filter offset in CMSIS-NN

Change-Id: I10a732d7ab0c7bb15ce6517e9ae1cb8a42d50b7e
---
 .../micro/kernels/cmsis_nn/fully_connected.cc | 21 ++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/tensorflow/lite/micro/kernels/cmsis_nn/fully_connected.cc b/tensorflow/lite/micro/kernels/cmsis_nn/fully_connected.cc
index d9729a5fb51..dbba5b27f58 100644
--- a/tensorflow/lite/micro/kernels/cmsis_nn/fully_connected.cc
+++ b/tensorflow/lite/micro/kernels/cmsis_nn/fully_connected.cc
@@ -104,7 +104,8 @@ TfLiteStatus Prepare(TfLiteContext* context, TfLiteNode* node) {
     TF_LITE_ENSURE_EQ(context, input->params.zero_point, 0);
     TF_LITE_ENSURE_EQ(context, output->params.zero_point, 0);
     buf_size = arm_fully_connected_s16_get_buffer_size(&filter_dims);
-  } else if (input->type == kTfLiteInt8) {
+  } else if (input->type == kTfLiteInt8 &&
+             data->reference_op_data.filter_zero_point == 0) {
     const RuntimeShape input_shape = GetTensorShape(input);
 
     TFLITE_DCHECK_GE(output_dim_count, 2);
@@ -374,8 +375,22 @@ TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
     case kTfLiteInt8: {
       switch (filter_int8.type) {
         case kTfLiteInt8:
-          return EvalQuantizedInt8(context, node, data, input, &filter_int8,
-                                   bias, output);
+          if (data.reference_op_data.filter_zero_point == 0) {
+            return EvalQuantizedInt8(context, node, data, input, &filter_int8,
+                                     bias, output);
+          } else {
+            tflite::reference_integer_ops::FullyConnected(
+                FullyConnectedParamsQuantized(data.reference_op_data),
+                tflite::micro::GetTensorShape(input),
+                tflite::micro::GetTensorData<int8_t>(input),
+                tflite::micro::GetTensorShape(filter),
+                tflite::micro::GetTensorData<int8_t>(filter),
+                tflite::micro::GetTensorShape(bias),
+                tflite::micro::GetOptionalTensorData<int32_t>(bias),
+                tflite::micro::GetTensorShape(output),
+                tflite::micro::GetTensorData<int8_t>(output));
+            return kTfLiteOk;
+          }
         default:
           MicroPrintf("Filter Type %s (%d) not supported.",
                       TfLiteTypeGetName(filter->type), filter->type);