Refactor kernel selection.

Early return in priority selection.

Change-Id: I435665df8ca29f5e148038f3836fdf53a4d33e2d

tflm/opt/conv_s8.cc

diff --git a/tflm/opt/conv_s8.cc b/tflm/opt/conv_s8.cc
index ce56fda..d3529ef 100644
--- a/tflm/opt/conv_s8.cc
+++ b/tflm/opt/conv_s8.cc
@@ -192,46 +192,49 @@
   const auto output_width = output_shape.Dims(2);
   const auto output_depth = output_shape.Dims(3);
 
-  // use generic implementation by default
-  auto fn = ConvS8Generic;
+#define RUN_KERNEL(kernel) {\
+  kernel(\
+      params, output_multiplier, output_shift, input_shape, input_data,\
+      filter_shape, filter_data, bias_shape, bias_data, output_shape,\
+      output_data);\
+  return; \
+}
 
   // special case of filter_depth = 4n
   if (dilation_width_factor == 1 && dilation_height_factor == 1 &&
       stride_width <= 2 && stride_height <= 2 && filter_depth % 4 == 0 &&
       output_depth >= 8 && output_width >= 8 && pad_width <= 1) {
-    fn = kelvin::opt::ConvS8D4;
+    RUN_KERNEL(kelvin::opt::ConvS8D4);
   }
 
   // special case of filter depth = 32n
-  else if (dilation_width_factor == 1 && dilation_height_factor == 1 &&
+  if (dilation_width_factor == 1 && dilation_height_factor == 1 &&
       stride_width <= 2 && stride_height <= 2 && filter_depth % 32 == 0) {
-    fn = kelvin::opt::ConvS8D32;
+    RUN_KERNEL(kelvin::opt::ConvS8D32);
   }
 
   // special case of filter size 1x1
-  else if (filter_height == 1 && filter_width == 1 && stride_height == 1 &&
+  if (filter_height == 1 && filter_width == 1 && stride_height == 1 &&
       stride_width == 1 && dilation_height_factor == 1 &&
       dilation_width_factor == 1 && pad_height == 0 && pad_width == 0 &&
       (output_depth % 8) == 0 && (input_depth % 32) == 0) {
     // TODO(ndodda): uncomment it when all tests are passed
-    // fn = kelvin::opt::ConvS8K1x1;
+    // RUN_KERNEL(kelvin::opt::ConvS8K1x1);
   }
 
   // special case of filter size 48x3x1x48
-  else if (batches == 1 && filter_height == 3 && filter_width == 1 &&
+  if (batches == 1 && filter_height == 3 && filter_width == 1 &&
       input_width == 1 && input_depth == 48 && output_depth == 48 &&
       stride_height == 1 && stride_width == 1 && dilation_height_factor == 1 &&
       dilation_width_factor == 1 && pad_height == 0 && pad_width == 0) {
-    fn = kelvin::opt::ConvS8K3x1D48;
+    RUN_KERNEL(kelvin::opt::ConvS8K3x1D48);
   }
 
-  else if (input_depth == 1 && ((output_depth % 4) == 0)) {
-    fn = kelvin::opt::ConvPerChannelD1;
+  if (input_depth == 1 && ((output_depth % 4) == 0)) {
+    RUN_KERNEL(kelvin::opt::ConvPerChannelD1);
   }
 
-  fn(params, output_multiplier, output_shift, input_shape, input_data,
-     filter_shape, filter_data, bias_shape, bias_data, output_shape,
-     output_data);
+  RUN_KERNEL(ConvS8Generic);
 }
 
 }  // namespace kelvin::opt