[moco-tf] Canonicalizer for TFRsqrt (#6723)

This will introduce Canonicalizer for TFRsqrt node that converts to "1/Sqrt(x)"

Signed-off-by: SaeHie Park <saehie.park@samsung.com>

diff --git a/compiler/moco-tf/src/Canonicalization/RsqrtCanonicalizer.cpp b/compiler/moco-tf/src/Canonicalization/RsqrtCanonicalizer.cpp
new file mode 100644 (file)
index 0000000..b4fbcac
--- /dev/null
+++ b/compiler/moco-tf/src/Canonicalization/RsqrtCanonicalizer.cpp
@@ -0,0 +1,166 @@
+/*
+ * 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 "RsqrtCanonicalizer.h"
+
+#include "Annotations/ShapeInferenceData.h"
+
+#include "Dialect/TFDialect.h"
+#include "Dialect/TFNodes.h"
+#include "Dialect/TFNodeVisitor.h"
+#include "Dialect/TFNodeImpl.h"
+
+#include <moco/Log.h>
+
+#include <loco/Service/TypeInference.h>
+
+#include <stdex/Memory.h>
+
+namespace
+{
+
+template <typename T>
+void prepare_const_gen(loco::ConstGen *const_node, const moco::tf::ShapeInferenceData *shapedata,
+                       T value);
+
+template <>
+void prepare_const_gen<float>(loco::ConstGen *const_node,
+                              const moco::tf::ShapeInferenceData *shapedata, float value)
+{
+  LOGGER(l);
+
+  uint32_t const_num_elements = 1;
+
+  auto dtype = loco::DataType::FLOAT32;
+  const_node->dtype(dtype);
+
+  auto rank = shapedata->rank();
+  const_node->rank(rank);
+  for (uint32_t r = 0; r < rank; ++r)
+  {
+    if (shapedata->dim(r).known())
+      const_node->dim(r) = shapedata->dim(r);
+    else
+      throw std::runtime_error("Cannot handle unknown shape");
+
+    assert(shapedata->dim(r).value() > 0);
+
+    const_num_elements *= shapedata->dim(r).value();
+  }
+
+  INFO(l) << "prepare_const_gen : Elements = " << const_num_elements;
+
+  const_node->size<loco::DataType::FLOAT32>(const_num_elements);
+  for (uint32_t i = 0; i < const_num_elements; ++i)
+  {
+    const_node->at<loco::DataType::FLOAT32>(i) = value;
+  }
+}
+
+bool canonicalize_rsqrt(loco::Graph *graph, moco::tf::TFRsqrt *node)
+{
+  /**
+   * @note This will replace TFRsqrt node with Canonical EltwiseSqrt + EltwiseRealDiv
+   *
+   *       Before
+   *                 A --- TFRsqrt -- C
+   *       After
+   *                    +- TFRsqrt --
+   *                    |
+   *                    |   ConstGen --+
+   *                    |               \
+   *                 A -+- EltwiseSqrt -- EltwiseDiv -- C
+   *
+   *       Where
+   *                 A : features of TFRsqrt
+   *                 C : a node that uses TFSqrt as an input
+   *                 TFRsqrt is disconnected from C
+   *                 TFRsqrt is converted to 1 / EltwiseSqrt
+   */
+
+  auto rsqrt_shapedata = node->annot<moco::tf::ShapeInferenceData>();
+  if (rsqrt_shapedata == nullptr)
+  {
+    // We need this shape information
+    assert(false); // this shouldn't happen, let's add an alarm
+    return false;
+  }
+
+  if (!loco::dtype_known(node))
+  {
+    // We need type of this node
+    return false;
+  }
+
+  auto sqrt_node = graph->nodes()->create<loco::EltwiseSqrt>();
+  auto eltdiv_node = graph->nodes()->create<loco::EltwiseDiv>();
+  auto const_node = graph->nodes()->create<loco::ConstGen>();
+
+  auto dtype = loco::dtype_get(node);
+
+  switch (dtype)
+  {
+    case loco::DataType::FLOAT32:
+      prepare_const_gen<float>(const_node, rsqrt_shapedata, 1.0f);
+      break;
+
+    default:
+      throw std::runtime_error("NYI for this DataType");
+  }
+
+  auto node_A = node->x();
+
+  // update connections
+  sqrt_node->input(node_A);
+  eltdiv_node->lhs(const_node);
+  eltdiv_node->rhs(sqrt_node);
+
+  // replace node
+  replace(node).with(eltdiv_node);
+
+  return true;
+}
+
+} // namespace
+
+namespace moco
+{
+namespace tf
+{
+
+bool RsqrtCanonicalizer::run(loco::Graph *graph)
+{
+  auto active_nodes = loco::active_nodes(loco::output_nodes(graph));
+  bool changed = false;
+
+  for (auto node : active_nodes)
+  {
+    if (node->dialect() == TFDialect::get())
+    {
+      auto tf_node = dynamic_cast<moco::tf::TFRsqrt *>(node);
+      if (tf_node != nullptr)
+      {
+        if (canonicalize_rsqrt(graph, tf_node))
+          changed = true;
+      }
+    }
+  }
+
+  return changed;
+}
+
+} // namespace tf
+} // namespace moco

diff --git a/compiler/moco-tf/src/Canonicalization/RsqrtCanonicalizer.h b/compiler/moco-tf/src/Canonicalization/RsqrtCanonicalizer.h
new file mode 100644 (file)
index 0000000..a58c0ad
--- /dev/null
+++ b/compiler/moco-tf/src/Canonicalization/RsqrtCanonicalizer.h
@@ -0,0 +1,44 @@
+/*
+ * 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_RSQRT_CANONICALIZER_H__
+#define __MOCO_TF_RSQRT_CANONICALIZER_H__
+
+#include "Transform.h"
+
+#include <loco.h>
+
+namespace moco
+{
+namespace tf
+{
+
+/**
+ * @brief  Convert TFRsqrt to Canonical EltwiseDiv + EltwiseSqrt
+ */
+class RsqrtCanonicalizer : public Transform
+{
+public:
+  const char *name(void) const final { return "RsqrtCanonicalizer"; }
+
+public:
+  bool run(loco::Graph *graph) override;
+};
+
+} // namespace tf
+} // namespace moco
+
+#endif // __MOCO_TF_RSQRT_CANONICALIZER_H__