Re-write dynamically quantized Conv2D as FC

PiperOrigin-RevId: 727589025

Author: alankelly

src/subgraph/convolution-2d.c

@@ -1105,7 +1105,7 @@ enum xnn_status xnn_define_convolution_2d(
     return status;
   }
 
-  const struct xnn_value* input_value = &subgraph->values[input_id];
+  struct xnn_value* input_value = &subgraph->values[input_id];
   status = xnn_subgraph_check_input_type_dense(xnn_node_type_convolution_2d, input_id, input_value);
   if (status != xnn_status_success) {
     return status;
@@ -1299,15 +1299,19 @@ enum xnn_status xnn_define_convolution_2d(
       }
     }
   }
-  if (input_value->datatype == output_value->datatype) {
-    const bool unit_subsampling = (subsampling_width | subsampling_height) == 1;
-    const size_t kernel_size = kernel_height * kernel_width;
-    if (groups == 1 && kernel_size == 1 && unit_subsampling && !any_padding) {
-      // Check if the convolution can take the vmulcaddc path.
-      if (group_input_channels + group_output_channels > 2) {
-        return xnn_define_fully_connected(subgraph, output_min, output_max,
-                                          input_id, filter_id, bias_id, output_id, /*flags=*/0);
+  const bool unit_subsampling = (subsampling_width | subsampling_height) == 1;
+  const size_t kernel_size = kernel_height * kernel_width;
+  if (groups == 1 && kernel_size == 1 && unit_subsampling && !any_padding) {
+    // Check if the convolution can take the vmulcaddc path.
+    if (group_input_channels + group_output_channels > 2) {
+      if (input_value->datatype == xnn_datatype_qdint8) {
+        // Dynammically quantized tensors for fully connected ops are quantized
+        // per-channel, not per-batch.
+        input_value->quantization.num_nonbatch_dims = 1;
+        input_value->quantization.dynamic_params_size =  xnn_tensor_get_dynamic_quant_param_size(input_value);
       }
+      return xnn_define_fully_connected(subgraph, output_min, output_max,
+                                        input_id, filter_id, bias_id, output_id, /*flags=*/0);
     }
   }
   struct xnn_node* node = xnn_subgraph_new_node(subgraph);