[RELAY][PASS] General OpFusion.

include/tvm/relay/expr.h

@@ -429,6 +429,16 @@ inline const TTypeNode* ExprNode::type_as() const {
   return node;
 }
 
+/*!
+ * \brief Print node as text format.
+ * \param node The node to be printed.
+ * \param annotate An optional callback function for attaching
+ *        additional comment block to an expr.
+ * \return The text representation.
+ */
+std::string RelayPrint(
+    const NodeRef& node,
+    runtime::TypedPackedFunc<std::string(Expr)> annotate = nullptr);
 }  // namespace relay
 }  // namespace tvm
 #endif  // TVM_RELAY_EXPR_H_

include/tvm/runtime/packed_func.h

@@ -161,6 +161,8 @@ class TypedPackedFunc<R(Args...)> {
   using TSelf = TypedPackedFunc<R(Args...)>;
   /*! \brief default constructor */
   TypedPackedFunc() {}
+  /*! \brief constructor from null */
+  TypedPackedFunc(std::nullptr_t null) {}  // NOLINT(*)
   /*!
    * \brief construct by wrap a PackedFunc
    *

python/tvm/relay/base.py

@@ -22,15 +22,20 @@ def register_relay_node(type_key=None):
 
 
 class RelayNode(NodeBase):
-    def astext(self):
+    """Base class of all relay node."""
+    def astext(self, annotate=None):
         """Get the text format of the expression.
 
         Returns
         -------
         text : str
             The text format of the expression.
+
+        annotate: Optional[relay.Expr->str]
+            Optional annotate function to provide additional
+            information in the comment block.
         """
-        return _expr._text_print(self)
+        return _expr.RelayPrint(self, annotate)
 
 
 @register_relay_node

python/tvm/relay/build_module.py

@@ -173,11 +173,13 @@ def build(func,
     else:
         tophub_context = autotvm.util.EmptyContext()
 
+    cfg = BuildConfig.current
+
     with tophub_context:
         func = optimize(func)
         # Fuse ops before running code gen
         func = ir_pass.infer_type(func)
-        func = ir_pass.fuse_ops(func)
+        func = ir_pass.fuse_ops(func, cfg.opt_level)
         # Graph code generation
         func = ir_pass.infer_type(func)
         graph_gen = _graph_gen.GraphRuntimeCodegen(mod=None, target=target)

python/tvm/relay/expr.py

@@ -6,7 +6,6 @@
 import numpy as _np
 from .base import RelayNode, register_relay_node
 from . import _make
-from . import _expr
 from . import ty as _ty
 from .._ffi import base as _base
 from .. import nd as _nd
@@ -477,7 +476,7 @@ def astext(self):
         text : str
             The text format of the tuple expression.
         """
-        return _expr._text_print(self.tuple_value)
+        return self.tuple_value.astext()
 
     def __getitem__(self, index):
         if index >= len(self):

python/tvm/relay/ir_pass.py

@@ -259,17 +259,20 @@ def structural_hash(value):
         raise TypeError(msg)
 
 
-def fuse_ops(expr):
+def fuse_ops(expr, opt_level=1):
     """Fuse operators in expr together.
 
     Parameters
     ----------
     expr : tvm.relay.Expr
         The input expression.
 
+    opt_level : int
+        The level of fuse optimization.
+
     Returns
     -------
     transformed_expr : tvm.relay.Expr
         Transformed expression, containing fused result.
     """
-    return _ir_pass.FuseOps(expr)
+    return _ir_pass.FuseOps(expr, opt_level)

src/common/arena.h

@@ -38,11 +38,29 @@ class Arena {
   /*!
    * \brief Allocate a space from Arena for type T
    * \param T the data type to be allocated
+   * \note The space of T is not initialized.
    */
   template<typename T>
-  T* Alloc() {
+  T* allocate_() {
     return static_cast<T*>(Alloc(sizeof(T), alignof(T)));
   }
+  /*!
+   * \brief Create a new instance of type T.
+   * \param args The constructor argument.
+   * \tparam T the type to be created.
+   * \tparam Args Arguments to the constructor.
+   *
+   * \return The allocated object.
+   * \note The type T must be simple type, or only contain
+   *  memory allocated from the same arena.
+   *  Otherwise the destructor needs to be called explicitly.
+   */
+  template<typename T, typename... Args>
+  T* make(Args&&... args) {
+    T* ptr = allocate_<T>();
+    new (ptr) T(std::forward<Args>(args)...);
+    return ptr;
+  }
 
  private:
   // page size 16 KB
@@ -87,6 +105,44 @@ class Arena {
   }
 };
 
+/*!
+ * \brief Link list node
+ * \tparam T the content data type
+ */
+template<typename T>
+struct LinkNode {
+  /*! \brief The content value */
+  T value;
+  /*! \brief pointer to the next location */
+  LinkNode<T>* next{nullptr};
+};
+/*!
+ * \brief LinkedList structure
+ * \tparam T the content data type
+ * \note This is a simple data structure that can be used together with the arena.
+ * \sa LinkNode
+ */
+template<typename T>
+struct LinkedList {
+  /*! \brief Head pointer */
+  LinkNode<T>* head{nullptr};
+  /*! \brief Tail pointer */
+  LinkNode<T>* tail{nullptr};
+  /*!
+   * \brief Push a new node to the end of the linked list.
+   * \param node The node to be pushed.
+   */
+  void Push(LinkNode<T>* node) {
+    node->next = nullptr;
+    if (this->tail != nullptr) {
+      this->tail->next = node;
+      this->tail = node;
+    } else {
+      head = tail = node;
+    }
+  }
+};
+
 }  // namespace common
 }  // namespace tvm
 #endif  // TVM_COMMON_ARENA_H_

src/relay/backend/compile_engine.cc

@@ -109,6 +109,29 @@ class ScheduleGetter :
     return {};
   }
 
+  Array<Tensor> VisitExpr_(const ConstantNode* op) final {
+    CHECK(op->is_scalar());
+    void* data = op->data->data;
+    DataType dtype = TVMType2Type(op->data->dtype);
+    Tensor value = tvm::compute({}, [&](const Array<tvm::Var>&) {
+        if (dtype == Int(32)) {
+          return make_const(dtype, static_cast<const int32_t*>(data)[0]);
+        } else if (dtype == Int(64)) {
+          return make_const(dtype, static_cast<const int64_t*>(data)[0]);
+        } else if (dtype == Float(32)) {
+          return make_const(dtype, static_cast<const float*>(data)[0]);
+        } else if (dtype == Float(64)) {
+          return make_const(dtype, static_cast<const double*>(data)[0]);
+        } else if (dtype == Bool()) {
+          return make_const(dtype, static_cast<const uint8_t*>(data)[0]);
+        } else {
+          LOG(FATAL) << "not handled";
+          return tvm::Expr();
+        }
+      });
+    return {value};
+  }
+
   Array<Tensor> VisitExpr_(const CallNode* call_node) final {
     static auto fcompute =
         Op::GetAttr<FTVMCompute>("FTVMCompute");

src/relay/ir/text_printer.cc

@@ -125,6 +125,8 @@ class TextPrinter :
     public TypeFunctor<void (const Type&, std::ostream& os)>,  // NOLINT(*)
     public AttrFunctor<void (const NodeRef&, std::ostream& os)> { // NOLINT(*)
  public:
+  explicit TextPrinter(runtime::TypedPackedFunc<std::string(Expr)> annotate)
+      : annotate_(annotate) {}
   /*!
    * \brief Print a node to string.
    * \param node.
@@ -279,11 +281,11 @@ class TextPrinter :
 
   TextValue VisitExpr_(const CallNode* op) final {
     // possibly through meta-data
-    TextValue call_op = GetValue(op->op);
     std::vector<TextValue> args;
     for (Expr arg : op->args) {
       args.emplace_back(GetValue(arg));
     }
+    TextValue call_op = GetValue(op->op);
     TextValue id = this->AllocTempVar();
     this->PrintIndent();
 
@@ -532,7 +534,9 @@ class TextPrinter :
    */
   void PrintOptionalInfo(const Expr& expr) {
     // additional information in comment.
-    if (expr->checked_type_.defined()) {
+    if (annotate_ != nullptr) {
+      stream_ << " # " << annotate_(expr);
+    } else if (expr->checked_type_.defined()) {
       stream_ << " # ty=";
       this->PrintType(expr->checked_type(), stream_);
     }
@@ -678,14 +682,19 @@ class TextPrinter :
       name = "%" + name;
     }
     TextValue val(GetUniqueName(name));
-    CHECK(!memo_.count(var)) << "Duplicated variable " << var;
+    // still print if ir is malformed, but show the error.
+    if (memo_.count(var)) {
+      memo_[var] = TextValue(val.name + "-malformed-ir");
+    }
     memo_[var] = val;
     return val;
   }
 
  private:
   class AttrPrinter;
   friend class AttrPrinter;
+  /*! \brief additional comment function */
+  runtime::TypedPackedFunc<std::string(Expr)> annotate_;
   /*! \brief meta data context */
   TextMetaDataContext meta_;
   /*! \brief Check whether scope is still valid */
@@ -776,12 +785,15 @@ void TextPrinter::PrintCallAttrs(const Expr& op,
   os << ", " << meta_.GetMetaNode(attrs);
 }
 
-std::string RelayPrint(const NodeRef& node) {
-  return TextPrinter().Print(node);
+std::string RelayPrint(const NodeRef& node,
+                       runtime::TypedPackedFunc<std::string(Expr)> annotate) {
+  return TextPrinter(annotate).Print(node);
 }
 
-TVM_REGISTER_API("relay._expr._text_print")
-.set_body_typed<std::string(const NodeRef&)>(RelayPrint);
+TVM_REGISTER_API("relay._expr.RelayPrint")
+.set_body_typed<std::string(
+    const NodeRef&,
+    runtime::TypedPackedFunc<std::string(Expr)>)>(RelayPrint);
 
 }  // namespace relay
 }  // namespace tvm

src/relay/pass/fold_scale_axis.cc

@@ -10,6 +10,7 @@
 #include <tvm/relay/attrs/nn.h>
 #include <tvm/relay/expr_functor.h>
 #include "pattern_util.h"
+#include "pass_util.h"
 #include "../op/nn/layout.h"
 
 namespace tvm {
@@ -580,23 +581,6 @@ using FBackwardTransform = TypedPackedFunc<
 //----------------------------------------------
 // Generic Visitors for FScaleAxisBackward
 //----------------------------------------------
-/*!
- * \brief Get reference counter of each internal ExprNode in body.
- * \param body The body expression.
- * \return The reference count mapping.
- */
-std::unordered_map<const Node*, size_t>
-GetExprRefCount(const Expr& body) {
-  class ExprRefCounter : private ExprVisitor {
-   public:
-    std::unordered_map<const Node*, size_t>
-    Get(const Expr& body) {
-      this->VisitExpr(body);
-      return std::move(this->visit_counter_);
-    }
-  };
-  return ExprRefCounter().Get(body);
-}
 
 class BackwardPrep : private ExprVisitor {
  public: