Add int16->int32 quantization to TFLM quantize op.

PiperOrigin-RevId: 339953940
Change-Id: I568589fc09fa6e5aae137e7e8533e1dab86190d3

tensorflow/lite/micro/kernels/quantize.cc

@@ -67,7 +67,8 @@ TfLiteStatus Prepare(TfLiteContext* context, TfLiteNode* node) {
                               input->type == kTfLiteInt8);
   TF_LITE_ENSURE(context, output->type == kTfLiteUInt8 ||
                               output->type == kTfLiteInt8 ||
-                              output->type == kTfLiteInt16);
+                              output->type == kTfLiteInt16 ||
+                              output->type == kTfLiteInt32);
 
   if (((input->type == kTfLiteInt16 || input->type == kTfLiteInt8) &&
        output->type == kTfLiteInt8) ||
@@ -139,6 +140,13 @@ TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
             data->quantization_params.zero_point,
             tflite::micro::GetTensorData<int16_t>(output));
         return kTfLiteOk;
+      case kTfLiteInt32:
+        reference_ops::Requantize(
+            tflite::micro::GetTensorData<int16_t>(input), size,
+            data->output_multiplier, data->output_shift, data->input_zero_point,
+            data->quantization_params.zero_point,
+            tflite::micro::GetTensorData<int32_t>(output));
+        return kTfLiteOk;
       default:
         TF_LITE_KERNEL_LOG(context, "Input %s, output %s not supported.",
                            TfLiteTypeGetName(input->type),

tensorflow/lite/micro/kernels/quantize_test.cc

@@ -282,4 +282,21 @@ TF_LITE_MICRO_TEST(QuantizeOpTestInt8toInt8NoZeroPoint) {
                                   output_zero_point, output_quantized);
 }
 
+TF_LITE_MICRO_TEST(QuantizeOpTestInt16toInt32) {
+  const int length = 10;
+  const int dims[] = {2, 2, 5};
+  const float values[] = {-32, -31, -30, -29, -28, 27, 28, 29, 30, 31};
+  const float input_scale = 1.f;
+  const int input_zero_point = 0;
+  const float output_scale = 0.5;
+  const int output_zero_point = 0;
+  int32_t output_quantized[length];
+  int32_t values_quantized[length];
+  int16_t input_quantized[length];
+  tflite::testing::TestRequantize(dims, values, input_quantized, input_scale,
+                                  input_zero_point, dims, values,
+                                  values_quantized, output_scale,
+                                  output_zero_point, output_quantized);
+}
+
 TF_LITE_MICRO_TESTS_END