!8163 Add irpass related to PrimTile.

Merge pull request !8163 from huangbingjian/add_irpass_tile

mindspore/ccsrc/frontend/optimizer/irpass.cc

@@ -69,7 +69,7 @@ OptimizeIRPassLib::OptimizeIRPassLib() {
   // ops eliminate
   item_tuple_eliminate_ = MakeSubstitution(std::make_shared<ItemTupleEliminater>(), "item_tuple_eliminate",
                                            {prim::kPrimTupleGetItem, prim::kPrimTupleSetItem, prim::kPrimListGetItem});
-  tile_eliminate_ = MakeSubstitution(std::make_shared<TileMultiplyByOne>(), "tile_eliminate", prim::kPrimTile);
+  tile_eliminate_ = MakeSubstitution(std::make_shared<TileEliminater>(), "tile_eliminate", prim::kPrimTile);
   cast_eliminate_ = MakeSubstitution(std::make_shared<CastEliminater>(), "cast_eliminate", prim::kPrimCast);
   reshape_eliminate_ = MakeSubstitution(std::make_shared<ReshapeEliminater>(), "reshape_eliminate", prim::kPrimReshape);
   transpose_eliminate_ =

mindspore/ccsrc/frontend/optimizer/irpass/tile_eliminate.h

@@ -29,8 +29,9 @@ namespace mindspore {
 namespace opt {
 namespace irpass {
 // check if node is value tuple and all one. e.g. (1, 1, 1)
-// {PrimTile, X, MultiOne}
-class TileMultiplyByOne : public AnfVisitor {
+// {PrimTile, X, MultiOne} -> X
+// {PrimTile, X, Empty} -> X
+class TileEliminater : public AnfVisitor {
  public:
   AnfNodePtr operator()(const OptimizerPtr &, const AnfNodePtr &node) override {
     Reset();
@@ -44,7 +45,7 @@ class TileMultiplyByOne : public AnfVisitor {
     auto value = GetValueNode(tuple_);
     auto elements = GetValue<std::vector<int>>(value);
     if (elements.empty()) {
-      return nullptr;
+      return x_;
     }
 
     auto cmp = std::all_of(elements.cbegin(), elements.cend(), [](int i) { return i == 1; });