[luci/pass] Support Div in ConvertNCHWToNHWC (#13525)

* [luci/pass] Support Div in ConvertNCHWToNHWC

This supports Div in ConvertNCHWToNHWC.

ONE-DCO-1.0-Signed-off-by: Hyukjin Jeong <[email protected]>

* Update comment

compiler/luci/pass/src/ConvertNCHWToNHWCPass.cpp

@@ -569,6 +569,40 @@ bool is_NCHW_with_const(const luci::CircleMul *node, luci::CircleNode *&pred_nod
   return true;
 }
 
+// TODO Merge this function with other elementwise Ops
+bool is_NCHW_with_const(const luci::CircleDiv *node, luci::CircleNode *&pred_node,
+                        luci::CircleConst *&const_node)
+{
+  auto x = dynamic_cast<luci::CircleConst *>(node->x());
+  auto y = dynamic_cast<luci::CircleConst *>(node->y());
+
+  if (x != nullptr && y == nullptr)
+  {
+    pred_node = loco::must_cast<luci::CircleNode *>(node->y());
+    const_node = x;
+  }
+  else if (x == nullptr && y != nullptr)
+  {
+    pred_node = loco::must_cast<luci::CircleNode *>(node->x());
+    const_node = y;
+  }
+  else
+  {
+    // Ignore if DIV does not have a const_node input.
+    return false;
+  }
+
+  if (pred_node->rank() != 4)
+    return false;
+
+  if (not broadcastable(const_node, node))
+    return false;
+
+  const_node = expand_to_rank_4(const_node);
+
+  return true;
+}
+
 // We assume ADD with const input is NCHW if,
 // Input shape: (N, C, H, W)
 // Output shape: (N, C, H, W)
@@ -832,6 +866,58 @@ class ConvertNCHWToNHWC final : public luci::CircleNodeMutableVisitor<bool>
     return true;
   }
 
+  bool visit(luci::CircleDiv *node)
+  {
+    LOGGER(l);
+
+    luci::CircleNode *pred_node = nullptr;
+    luci::CircleConst *constant = nullptr;
+
+    if (is_NCHW_with_const(node, pred_node, constant))
+    {
+      assert(constant->rank() == 4); // FIX is_NCHW_with_const unless
+      auto nhwc_const = create_NHWC_from_NCHW(constant);
+      if (nhwc_const == nullptr)
+        return false;
+      node->y(nhwc_const);
+
+      auto pre_trans = create_pre_transpose(node);
+      pre_trans->a(pred_node);
+      node->x(pre_trans);
+    }
+    else if (constant == nullptr)
+    {
+      // Only support for input rank 4
+      auto input_x = loco::must_cast<luci::CircleNode *>(node->x());
+      if (input_x->rank() != 4)
+        return false;
+      auto input_y = loco::must_cast<luci::CircleNode *>(node->y());
+      if (input_y->rank() != 4)
+        return false;
+
+      auto pre_trans_x = create_pre_transpose(node);
+      pre_trans_x->a(input_x);
+      node->x(pre_trans_x);
+
+      auto pre_trans_y = create_pre_transpose(node);
+      pre_trans_y->a(input_y);
+      node->y(pre_trans_y);
+    }
+    else
+    {
+      return false;
+    }
+
+    // Do shape inference for this node again.
+    node->shape_status(luci::ShapeStatus::UNDEFINED);
+
+    auto post_trans = create_post_transpose(node);
+    loco::replace(node).with(post_trans);
+
+    post_trans->a(node);
+    return true;
+  }
+
   bool visit(luci::CircleElu *node) { return convert_unary_features<luci::CircleElu>(node); }
 
   bool visit(luci::CircleGelu *node) { return convert_unary_features<luci::CircleGelu>(node); }
@@ -1538,6 +1624,7 @@ bool ConvertNCHWToNHWCPass::run(loco::Graph *g)
       // tflite/circle assumes the last channel is always axis
       case luci::CircleOpcode::ADD:
       case luci::CircleOpcode::CONCATENATION:
+      case luci::CircleOpcode::DIV:
       case luci::CircleOpcode::ELU:
       case luci::CircleOpcode::GELU:
       case luci::CircleOpcode::LEAKY_RELU:

compiler/luci/pass/src/ConvertNCHWToNHWCPass.test.cpp

@@ -435,6 +435,54 @@ class ConcatenationGraph final : public SimpleGraph
   luci::CircleConst *input2 = nullptr;
 };
 
+class DivGraph final : public SimpleGraph
+{
+protected:
+  loco::Node *insertGraphBody(loco::Node *input) override
+  {
+    div = g.nodes()->create<luci::CircleDiv>();
+    constant = g.nodes()->create<luci::CircleConst>();
+
+    div->dtype(loco::DataType::FLOAT32);
+    constant->dtype(loco::DataType::FLOAT32);
+
+    uint32_t channel_size = 16;
+    div->shape({1, channel_size, 4, 4});
+    constant->shape({1, channel_size, 1, 1});
+
+    constant->size<loco::DataType::FLOAT32>(channel_size);
+    for (uint32_t i = 0; i < channel_size; i++)
+    {
+      constant->at<loco::DataType::FLOAT32>(i) = i;
+    }
+
+    div->x(input);
+    div->y(constant);
+
+    div->name("div");
+    constant->name("constant");
+
+    return div;
+  }
+
+public:
+  void update_const_shape_to_nchw(void)
+  {
+    uint32_t channel_size = 16;
+    constant->shape({1, channel_size, 4, 4});
+
+    constant->size<loco::DataType::FLOAT32>(channel_size * 4 * 4);
+    for (uint32_t i = 0; i < channel_size; i++)
+    {
+      constant->at<loco::DataType::FLOAT32>(i) = i;
+    }
+  }
+
+public:
+  luci::CircleDiv *div = nullptr;
+  luci::CircleConst *constant = nullptr;
+};
+
 class EluGraph final : public SimpleGraph
 {
 protected:
@@ -1382,6 +1430,35 @@ TEST(ConvertNCHWToNHWC, Concatenation)
   EXPECT_EQ(3, g.concat->axis());
 }
 
+TEST(ConvertNCHWToNHWC, Div)
+{
+  DivGraph g;
+  g.init();
+
+  run_phase(&g.g, false, false);
+
+  auto input_succs = loco::succs(g.input);
+  EXPECT_EQ(1, input_succs.size());
+  check_post_trans(*input_succs.begin());
+
+  check_pre_trans(g.div->x());
+
+  auto div_succs = loco::succs(g.div);
+  EXPECT_EQ(1, div_succs.size());
+  check_post_trans(*div_succs.begin());
+
+  uint32_t channel_size = 16;
+  auto new_constant = dynamic_cast<luci::CircleConst *>(g.div->y());
+  EXPECT_NE(nullptr, new_constant);
+  EXPECT_EQ(4, new_constant->rank());
+  EXPECT_EQ(1, new_constant->dim(0).value());
+  EXPECT_EQ(1, new_constant->dim(1).value());
+  EXPECT_EQ(1, new_constant->dim(2).value());
+  EXPECT_EQ(channel_size, new_constant->dim(3).value());
+
+  check_pre_trans(g.output->from());
+}
+
 TEST(ConvertNCHWToNHWC, Elu)
 {
   EluGraph g;