1 files changed, 172 insertions, 0 deletions
diff --git a/compiler/luci/pass/src/RemoveUnnecessaryReshapeNetPass.cpp b/compiler/luci/pass/src/RemoveUnnecessaryReshapeNetPass.cpp
new file mode 100644
index 000000000..476ec68bf
--- /dev/null
+++ b/compiler/luci/pass/src/RemoveUnnecessaryReshapeNetPass.cpp
@@ -0,0 +1,172 @@
+/*
+ * Copyright (c) 2022 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "luci/Pass/RemoveUnnecessaryReshapeNetPass.h"
+
+#include <luci/IR/CircleNodes.h>
+
+namespace
+{
+
+bool acceptable_intermediate_op(const loco::Node *node)
+{
+  if (not node)
+    return false;
+
+  const auto opcode = loco::must_cast<const luci::CircleNode *>(node)->opcode();
+
+  switch (opcode)
+  {
+    case luci::CircleOpcode::ADD:
+    case luci::CircleOpcode::MUL:
+    case luci::CircleOpcode::TANH:
+    case luci::CircleOpcode::LOGISTIC:
+      break;
+
+    default:
+      return false;
+  }
+
+  return true;
+}
+
+bool same_shape(const loco::Node *a, const loco::Node *b)
+{
+  auto a_cnode = loco::must_cast<const luci::CircleNode *>(a);
+  auto b_cnode = loco::must_cast<const luci::CircleNode *>(b);
+
+  if (a_cnode->rank() != b_cnode->rank())
+    return false;
+
+  for (uint32_t i = 0; i < a_cnode->rank(); i++)
+  {
+    if (not(a_cnode->dim(i) == b_cnode->dim(i)))
+      return false;
+  }
+  return true;
+}
+
+class PreReshapeFinder
+{
+public:
+  PreReshapeFinder(const luci::CircleReshape *post_reshape) : _post_reshape(post_reshape)
+  {
+    assert(post_reshape != nullptr); // FIX_CALLER_UNLESS
+  }
+
+public:
+  // Return true if pre_reshapes are found
+  bool collect_pre_reshapes(loco::Node *node)
+  {
+    // TODO Support diamond case
+    if (loco::succs(node).size() != 1)
+      return false;
+
+    if (auto pre_reshape = dynamic_cast<luci::CircleReshape *>(node))
+    {
+      // Check ifm of pre-reshape and ofm of post_reshape
+      if (not same_shape(pre_reshape->tensor(), _post_reshape))
+        return false;
+
+      // Check ofm of pre-reshape and ifm of post_reshape
+      if (not same_shape(pre_reshape, _post_reshape->tensor()))
+        return false;
+
+      _pre_reshapes.emplace_back(pre_reshape);
+      return true;
+    }
+
+    if (not acceptable_intermediate_op(node))
+      return false;
+
+    for (uint32_t i = 0; i < node->arity(); i++)
+    {
+      if (not collect_pre_reshapes(node->arg(i)))
+        return false;
+    }
+
+    return true;
+  }
+
+public:
+  std::vector<luci::CircleReshape *> pre_reshapes(void) const { return _pre_reshapes; }
+
+private:
+  const luci::CircleReshape *_post_reshape = nullptr;
+  std::vector<luci::CircleReshape *> _pre_reshapes;
+};
+
+bool remove_unnecessary_reshape_net(luci::CircleReshape *reshape)
+{
+  PreReshapeFinder finder(reshape);
+  if (not finder.collect_pre_reshapes(reshape->tensor()))
+    return false;
+
+  // Remove pre_reshapes
+  for (auto pre_reshape : finder.pre_reshapes())
+  {
+    loco::replace(pre_reshape).with(pre_reshape->tensor());
+  }
+
+  // Remove post_reshape
+  loco::replace(reshape).with(reshape->tensor());
+
+  return true;
+}
+
+} // namespace
+
+namespace luci
+{
+
+/**
+ * BEFORE
+ *
+ *      [CircleNode]
+ *            |
+ *    [CircleReshape_1] (shape: A -> B)
+ *            |
+ *      [CircleNode] (ex: Add/Mul/Tanh/Logistic ..)
+ *            |
+ *    [CircleReshape_2] (shape: B -> A)
+ *            |
+ *      [CircleNode]
+ *
+ * AFTER
+ *
+ *      [CircleNode]
+ *            |   \
+ *            |   [CircleReshape_1]
+ *      [CircleNode]
+ *            |   \
+ *            |   [CircleReshape_2]
+ *      [CircleNode]
+ **/
+bool RemoveUnnecessaryReshapeNetPass::run(loco::Graph *g)
+{
+  bool changed = false;
+  for (auto node : loco::active_nodes(loco::output_nodes(g)))
+  {
+    if (auto reshape_node = dynamic_cast<luci::CircleReshape *>(node))
+    {
+      if (remove_unnecessary_reshape_net(reshape_node))
+        changed = true;
+    }
+  }
+  return changed;
+}
+
+} // namespace luci