Misc. small optimizations in Grappler and shape inference code.

Impact on time per optimizer on inception graph:

model_pruner:          590 ms -> 550 ms   (-7%)
function_optimizer:    130 ms -> 130 ms   (-0%)
constant_folding:     7600 ms -> 7550 ms  (-0.7%)
arithmetic_optimizer: 1860 ms -> 1550 ms  (-20%)
loop_optimizer:        320 ms -> 320 ms   (-0%)
dependency_optimizer: 1300 ms -> 720 ms   (-45%)
layout:               1400 ms -> 1400 ms  (-0%)
memory_optimizer:     4200 ms -> 3540 ms  (-16%)
PiperOrigin-RevId: 192694528

1 files changed, 11 insertions, 30 deletions

diff --git a/tensorflow/core/grappler/utils.cc b/tensorflow/core/grappler/utils.cc
index 534fe670e0..7398d2c896 100644
--- a/tensorflow/core/grappler/utils.cc
+++ b/tensorflow/core/grappler/utils.cc
@@ -142,38 +142,12 @@ bool IsSameInput(const string& name1, const string& name2) {
     return true;
   }
   int position1;
-  string node1 = ParseNodeName(name1, &position1);
+  StringPiece node1 = ParseNodeNameAsStringPiece(name1, &position1);
   int position2;
-  string node2 = ParseNodeName(name2, &position2);
+  StringPiece node2 = ParseNodeNameAsStringPiece(name2, &position2);
   return (position1 == position2) && (node1 == node2);
 }
 
-string ParseNodeName(const string& name, int* position) {
-  // Strip the prefix '^' (if any), and strip the trailing ":{digits} (if any)
-  // to get a node name.
-  strings::Scanner scan(name);
-  scan.ZeroOrOneLiteral("^")
-      .RestartCapture()
-      .One(strings::Scanner::LETTER_DIGIT_DOT_UNDERSCORE)
-      .Any(strings::Scanner::LETTER_DIGIT_DASH_DOT_SLASH_UNDERSCORE);
-  StringPiece capture;
-  StringPiece remaining;
-  if (scan.Peek(':') != ':' || !scan.GetResult(&remaining, &capture)) {
-    *position = 0;
-    return "";
-  } else {
-    if (name[0] == '^') {
-      *position = -1;
-    } else if (remaining.empty()) {
-      *position = 0;
-    } else {
-      // Skip the first ':' character.
-      CHECK(strings::safe_strto32(remaining.substr(1), position));
-    }
-    return capture.ToString();
-  }
-}
-
 bool IsControlInput(const string& name) {
   return !name.empty() && name[0] == '^';
 }
@@ -185,7 +159,7 @@ string NodeName(const string& name) {
 
 int NodePosition(const string& name) {
   int position;
-  ParseNodeName(name, &position);
+  ParseNodeNameAsStringPiece(name, &position);
   return position;
 }
 
@@ -275,13 +249,20 @@ int NumNonControlInputs(const NodeDef& node) {
 
 int NumNonControlOutputs(const NodeDef& node, const NodeMap& node_map) {
   int num_outputs = 0;
+  int pos;
   for (const NodeDef* output : node_map.GetOutputs(node.name())) {
     for (const string& node_as_input : output->input()) {
       if (IsControlInput(node_as_input)) {
         break;
       }
-      if (NodeName(node_as_input) == node.name()) {
+      if (node_as_input == node.name()) {
         ++num_outputs;
+      } else {
+        const StringPiece name =
+            ParseNodeNameAsStringPiece(node_as_input, &pos);
+        if (name == node.name()) {
+          ++num_outputs;
+        }
       }
     }
   }