[turbofan] Refactor IsSame into NodeProperties.

src/compiler/js-call-reducer.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/js-call-reducer.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
@@ skipping 205 matching lines @@
   node->ReplaceInput(3, frame_state);
   node->ReplaceInput(4, effect);
   node->ReplaceInput(5, control);
   node->TrimInputCount(6);
   NodeProperties::ChangeOp(node, javascript()->OrdinaryHasInstance());
   return Changed(node);
 }
 
 namespace {
 
-// TODO(turbofan): Shall we move this to the NodeProperties? Or some (untyped)
-// alias analyzer?
-bool IsSame(Node* a, Node* b) {
-  if (a == b) {
-    return true;
-  } else if (a->opcode() == IrOpcode::kCheckHeapObject) {
-    return IsSame(a->InputAt(0), b);
-  } else if (b->opcode() == IrOpcode::kCheckHeapObject) {
-    return IsSame(a, b->InputAt(0));
-  }
-  return false;
-}
-
 // TODO(turbofan): Share with similar functionality in JSInliningHeuristic
 // and JSNativeContextSpecialization, i.e. move to NodeProperties helper?!
 MaybeHandle<Map> InferReceiverMap(Node* node) {
   Node* receiver = NodeProperties::GetValueInput(node, 1);
   Node* effect = NodeProperties::GetEffectInput(node);
   // Check if the {node} is dominated by a CheckMaps with a single map
   // for the {receiver}, and if so use that map for the lowering below.
   for (Node* dominator = effect;;) {
     if (dominator->opcode() == IrOpcode::kCheckMaps &&
-        IsSame(dominator->InputAt(0), receiver)) {
+        NodeProperties::IsSame(dominator->InputAt(0), receiver)) {
       if (dominator->op()->ValueInputCount() == 2) {
         HeapObjectMatcher m(dominator->InputAt(1));
         if (m.HasValue()) return Handle<Map>::cast(m.Value());
       }
       return MaybeHandle<Map>();
     }
     if (dominator->op()->EffectInputCount() != 1) {
       // Didn't find any appropriate CheckMaps node.
       return MaybeHandle<Map>();
     }
@@ skipping 422 matching lines @@
   return jsgraph()->javascript();
 }
 
 SimplifiedOperatorBuilder* JSCallReducer::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8