diff --git a/tensorflow/core/graph/edgeset.cc b/tensorflow/core/graph/edgeset.cc
index 2e0c6714616..e3b88994b5e 100644
--- a/tensorflow/core/graph/edgeset.cc
+++ b/tensorflow/core/graph/edgeset.cc
@@ -38,9 +38,8 @@ std::pair<EdgeSet::const_iterator, bool> EdgeSet::insert(value_type value) {
     }
     // array is full. convert to set.
     s = new std::set<const Edge*>;
-    for (int i = 0; i < kInline; i++) {
-      s->insert(static_cast<const Edge*>(ptrs_[i]));
-    }
+    s->insert(reinterpret_cast<const Edge**>(std::begin(ptrs_)),
+              reinterpret_cast<const Edge**>(std::end(ptrs_)));
     ptrs_[0] = this;
     ptrs_[1] = s;
     // fall through.
diff --git a/tensorflow/core/graph/graph_constructor.cc b/tensorflow/core/graph/graph_constructor.cc
index f6d83d5f6ff..ac1b690df31 100644
--- a/tensorflow/core/graph/graph_constructor.cc
+++ b/tensorflow/core/graph/graph_constructor.cc
@@ -35,6 +35,8 @@ limitations under the License.
 #include "tensorflow/core/graph/graph.h"
 #include "tensorflow/core/graph/tensor_id.h"
 #include "tensorflow/core/lib/core/errors.h"
+#include "tensorflow/core/lib/gtl/flatmap.h"
+#include "tensorflow/core/lib/gtl/flatset.h"
 #include "tensorflow/core/lib/gtl/inlined_vector.h"
 #include "tensorflow/core/lib/strings/scanner.h"
 #include "tensorflow/core/lib/strings/str_util.h"
@@ -268,22 +270,20 @@ class GraphConstructor {
     int gdef_index;
     Node* node;  // nullptr until the NodeDef is converted to a Node.
   };
-  // TODO(vrv): Profile this data structure to see if we should use an
-  // alternative implementation of std::unordered_map.
-  std::unordered_map<StringPiece, NodeInfo, StringPieceHasher> gdef_nodes_;
+  gtl::FlatMap<StringPiece, NodeInfo, StringPieceHasher> gdef_nodes_;
 
   // Prefixes already used in the GraphDef being imported.
-  std::unordered_set<StringPiece, StringPieceHasher> gdef_prefixes_;
+  gtl::FlatSet<StringPiece, StringPieceHasher> gdef_prefixes_;
 
   // Mapping from node name to the existing node in g_.
-  std::unordered_map<StringPiece, Node*, StringPieceHasher> existing_nodes_;
+  gtl::FlatMap<StringPiece, Node*, StringPieceHasher> existing_nodes_;
 
   // Prefixes already used in the graph.
-  std::unordered_set<StringPiece, StringPieceHasher> existing_prefixes_;
+  gtl::FlatSet<StringPiece, StringPieceHasher> existing_prefixes_;
 
   // Imported node names that have been uniquified. The key is the original
   // name, the value is the new unique name.
-  std::unordered_map<string, string> uniquified_names_;
+  gtl::FlatMap<string, string> uniquified_names_;
 
   // Index of NodeDefs in node_defs_ with all inputs already converted. We use a
   // (sorted) set so nodes are created in the order defined in the GraphDef.
@@ -360,7 +360,7 @@ bool NodeNameInValues(const std::vector<string>& control_dependencies,
 // Adds any prefixes of `node_name` (not including the full name itself) to
 // `prefixes`.
 void AddPrefixes(StringPiece node_name,
-                 std::unordered_set<StringPiece, StringPieceHasher>* prefixes) {
+                 gtl::FlatSet<StringPiece, StringPieceHasher>* prefixes) {
   size_t idx = -1;
   while ((idx = node_name.find('/', idx + 1)) != StringPiece::npos) {
     prefixes->insert(node_name.substr(0, idx));
@@ -857,7 +857,7 @@ void GraphConstructor::UpdateUniquifiedColocationNames() {
     for (int i = 0; i < coloc_values.size(); ++i) {
       StringPiece val(coloc_values[i]);
       if (str_util::ConsumePrefix(&val, kColocationGroupPrefix)) {
-        const auto& name_pair = uniquified_names_.find(string(val));
+        auto name_pair = uniquified_names_.find(string(val));
         if (name_pair == uniquified_names_.end()) continue;
         updated = true;
         coloc_values[i] =