[moco/tf] Implement forward node elimination (#4027)

This commit implements forward node elimination as a part of moco.tf
compilation pipeline.

Note that this transform is off by default.

Signed-off-by: Jonghyun Park <jh1302.park@samsung.com>

diff --git a/contrib/moco-tf/src/Knob.lst b/contrib/moco-tf/src/Knob.lst
index 428716c..91dd355 100644 (file)
--- a/contrib/moco-tf/src/Knob.lst
+++ b/contrib/moco-tf/src/Knob.lst
@@ -3,3 +3,4 @@
 #endif // KNOB_BOOL
 
 // KNOB_BOOL(NAME, DEFAULT_VALUE, DESCRIPTION)
+KNOB_BOOL(RemoveForwardNode, false, Enable RemoveForwardNode optimization)

diff --git a/contrib/moco-tf/src/Optimizer.cpp b/contrib/moco-tf/src/Optimizer.cpp
index 62e5880..3e9a9af 100644 (file)
--- a/contrib/moco-tf/src/Optimizer.cpp
+++ b/contrib/moco-tf/src/Optimizer.cpp
@@ -16,7 +16,11 @@
 
 #include "Optimizer.h"
 
+#include "Knob.h"
 #include "Phase.h"
+#include "Transforms.h"
+
+#include <stdex/Memory.h>
 
 namespace moco
 {
@@ -28,7 +32,10 @@ void Optimizer::optimize(loco::Graph *g) const
   moco::tf::Phase phase;
 
   /* TRANSFORM DECLARATION BEGIN */
-
+  if (moco::tf::get<moco::tf::Knob::RemoveForwardNode>())
+  {
+    phase.emplace_back(stdex::make_unique<RemoveForwardNodeTransform>());
+  }
   /* TRANSFORM DECLARATION END */
 
   moco::tf::PhaseRunner<moco::tf::PhaseStrategy::Saturate> phase_runner{g};

diff --git a/contrib/moco-tf/src/Optimizer.test.cpp b/contrib/moco-tf/src/Optimizer.test.cpp
index 5879af4..486ee7e 100644 (file)
--- a/contrib/moco-tf/src/Optimizer.test.cpp
+++ b/contrib/moco-tf/src/Optimizer.test.cpp
@@ -31,3 +31,27 @@ TEST(Optimizer, empty_graph)
 
   SUCCEED();
 }
+
+TEST(Optimizer, simple_forward_graph)
+{
+  moco::tf::Optimizer o;
+
+  /**
+   * Create a simple graph that forwards a constant as output
+   */
+  loco::Graph g;
+  {
+    auto constgen = g.nodes()->create<loco::ConstGen>();
+    constgen->shape({2, 3});
+
+    auto forward = g.nodes()->create<loco::Forward>();
+    forward->input(constgen);
+
+    auto pull = g.nodes()->create<loco::Push>();
+    pull->from(forward);
+  }
+
+  o.optimize(&g);
+
+  SUCCEED();
+}

diff --git a/contrib/moco-tf/src/Transforms.h b/contrib/moco-tf/src/Transforms.h
index 5d6e09f..541d961 100644 (file)
--- a/contrib/moco-tf/src/Transforms.h
+++ b/contrib/moco-tf/src/Transforms.h
@@ -20,5 +20,6 @@
 #include "Transforms/ClearAnnotTransform.h"
 #include "Transforms/FixPaddingTransform.h"
 #include "Transforms/FixShapeTransform.h"
+#include "Transforms/RemoveForwardNodeTransform.h"
 
 #endif // __MOCO_TF_TRANSFORMS_H__

diff --git a/contrib/moco-tf/src/Transforms/RemoveForwardNodeTransform.cpp b/contrib/moco-tf/src/Transforms/RemoveForwardNodeTransform.cpp
new file mode 100644 (file)
index 0000000..c3923a1
--- /dev/null
+++ b/contrib/moco-tf/src/Transforms/RemoveForwardNodeTransform.cpp
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2019 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 "RemoveForwardNodeTransform.h"
+
+#include <loco/IR/CanonicalDialect.h>
+#include <loco/IR/CanonicalNode.h>
+
+#include <set>
+
+namespace moco
+{
+namespace tf
+{
+
+bool RemoveForwardNodeTransform::run(loco::Graph *g)
+{
+  struct Collector final : public loco::CanonicalNodeMutableVisitor<void>
+  {
+    void visit(loco::Forward *node) final
+    {
+      if (node->input() != nullptr)
+      {
+        candidates.insert(node);
+      }
+    }
+
+    void visit(loco::Node *) final { return; }
+
+    std::set<loco::Forward *> candidates;
+  };
+
+  Collector collector;
+
+  for (auto node : loco::all_nodes(g))
+  {
+    if (node->dialect() == loco::CanonicalDialect::get())
+    {
+      auto canonical_node = dynamic_cast<loco::CanonicalNode *>(node);
+      canonical_node->accept(&collector);
+    }
+  }
+
+  for (auto node : collector.candidates)
+  {
+    replace(node).with(node->input());
+    node->input(nullptr);
+  }
+
+  return collector.candidates.size() > 0;
+}
+
+} // namespace tf
+} // namespace moco

diff --git a/contrib/moco-tf/src/Transforms/RemoveForwardNodeTransform.h b/contrib/moco-tf/src/Transforms/RemoveForwardNodeTransform.h
new file mode 100644 (file)
index 0000000..e64771a
--- /dev/null
+++ b/contrib/moco-tf/src/Transforms/RemoveForwardNodeTransform.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2019 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.
+ */
+
+#ifndef __MOCO_TF_REMOVE_FORWARD_NODE_TRANSFORM_H__
+#define __MOCO_TF_REMOVE_FORWARD_NODE_TRANSFORM_H__
+
+#include "Transform.h"
+
+namespace moco
+{
+namespace tf
+{
+
+/**
+ * @brief Use the input of "Forward" node instead
+ *
+ * BEFORE:
+ *   [X] -> [Forward] -> [Y]
+ *
+ * AFTER:
+ *   [X]       ->        [Y]
+ *          [Forward]
+ *
+ * NOTE This transform does not remove "Forward" node
+ */
+struct RemoveForwardNodeTransform final : public Transform
+{
+  const char *name(void) const final { return "RemoveForwardNodeTransform"; }
+
+  bool run(loco::Graph *g) final;
+};
+
+} // namespace tf
+} // namespace moco
+
+#endif // __MOCO_TF_REMOVE_FORWARD_NODE_TRANSFORM_H__