!12301 [GraphKernel] Eliminate redundant split nodes.

From: @tronzhang
Reviewed-by: @gaoxiong1,@anyrenwei
Signed-off-by: @anyrenwei

mindspore/ccsrc/backend/optimizer/graph_kernel/shape_ops_splitter.cc

@@ -16,6 +16,7 @@
 #include "backend/optimizer/graph_kernel/shape_ops_splitter.h"
 #include <algorithm>
 #include <vector>
+#include <set>
 #include <string>
 #include <unordered_set>
 #include <utility>
@@ -50,18 +51,24 @@ AnfNodePtr CloneCNode(const AnfNodePtr &anf_node) {
 }
 
 void SplitNode(const AnfNodePtr &node, const FuncGraphManagerPtr &mng) {
-  auto &users = mng->node_users();
-  AnfNodePtrList splitted_nodes;
-  for (size_t i = 0; i < users[node].size(); ++i) {
-    splitted_nodes.push_back(CloneCNode(node));
+  const auto &index_set = mng->node_users()[node];
+  std::map<AnfNodePtr, std::vector<int>> users_info;
+  std::for_each(index_set.cbegin(), index_set.cend(), [&users_info](const std::pair<AnfNodePtr, int> &iter) {
+    users_info[iter.first].push_back(iter.second);
+  });
+
+  AnfNodePtrList split_nodes;
+  for (size_t i = 0; i < users_info.size(); ++i) {
+    split_nodes.push_back(CloneCNode(node));
   }
 
-  const auto &index_set = users[node];
   int i = 0;
-  for (auto [user, index] : index_set) {
+  for (auto [user, indices] : users_info) {
     auto user_node = user->cast<CNodePtr>();
     MS_EXCEPTION_IF_NULL(user_node);
-    user_node->set_input(index, splitted_nodes[i]);
+    for (auto index : indices) {
+      user_node->set_input(index, split_nodes[i]);
+    }
     i++;
   }
 }
@@ -69,9 +76,11 @@ void SplitNode(const AnfNodePtr &node, const FuncGraphManagerPtr &mng) {
 
 bool ShapeOpsSplitter::IsMultiUserShapeOps(const AnfNodePtr &node, const FuncGraphManagerPtr &mng) {
   auto &users = mng->node_users();
-  return users[node].size() > 1 && std::any_of(shape_ops_.begin(), shape_ops_.end(), [&node](const PrimitivePtr &prim) {
-           return IsPrimitiveCNode(node, prim);
-         });
+  std::set<AnfNodePtr> user_set;
+  std::transform(users[node].cbegin(), users[node].cend(), std::inserter(user_set, user_set.end()),
+                 [](const std::pair<AnfNodePtr, int> &iter) { return iter.first; });
+  return user_set.size() > 1 && std::any_of(shape_ops_.begin(), shape_ops_.end(),
+                                            [&node](const PrimitivePtr &prim) { return IsPrimitiveCNode(node, prim); });
 }
 
 bool ShapeOpsSplitter::Process(const FuncGraphPtr &func_graph) {