[turbofan] Refactor IsSame into NodeProperties.

BUG=

Review-Url: https://codereview.chromium.org/2635243002
Cr-Commit-Position: refs/heads/master@{#42439}

src/compiler/js-builtin-reducer.cc

@@ -108,19 +108,6 @@ JSBuiltinReducer::JSBuiltinReducer(Editor* editor, JSGraph* jsgraph,
 
 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;
-}
-
 MaybeHandle<Map> GetMapWitness(Node* node) {
   Node* receiver = NodeProperties::GetValueInput(node, 1);
   Node* effect = NodeProperties::GetEffectInput(node);
@@ -128,7 +115,7 @@ MaybeHandle<Map> GetMapWitness(Node* node) {
   // 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)) {
       ZoneHandleSet<Map> const& maps =
           CheckMapsParametersOf(dominator->op()).maps();
       return (maps.size() == 1) ? MaybeHandle<Map>(maps[0])
@@ -914,7 +901,7 @@ bool HasInstanceTypeWitness(Node* receiver, Node* effect,
                             InstanceType instance_type) {
   for (Node* dominator = effect;;) {
     if (dominator->opcode() == IrOpcode::kCheckMaps &&
-        IsSame(dominator->InputAt(0), receiver)) {
+        NodeProperties::IsSame(dominator->InputAt(0), receiver)) {
       ZoneHandleSet<Map> const& maps =
           CheckMapsParametersOf(dominator->op()).maps();
       // Check if all maps have the given {instance_type}.
@@ -1621,7 +1608,7 @@ Node* GetStringWitness(Node* node) {
   // the lowering below.
   for (Node* dominator = effect;;) {
     if (dominator->opcode() == IrOpcode::kCheckString &&
-        IsSame(dominator->InputAt(0), receiver)) {
+        NodeProperties::IsSame(dominator->InputAt(0), receiver)) {
       return dominator;
     }
     if (dominator->op()->EffectInputCount() != 1) {

src/compiler/js-call-reducer.cc

@@ -223,19 +223,6 @@ Reduction JSCallReducer::ReduceFunctionPrototypeHasInstance(Node* 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) {
@@ -245,7 +232,7 @@ MaybeHandle<Map> InferReceiverMap(Node* node) {
   // 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());

src/compiler/js-inlining.cc

@@ -278,19 +278,6 @@ Node* JSInliner::CreateTailCallerFrameState(Node* node, Node* frame_state) {
 
 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(bmeurer): Unify this with the witness helper functions in the
 // js-builtin-reducer.cc once we have a better understanding of the
 // map tracking we want to do, and eventually changed the CheckMaps
@@ -305,7 +292,7 @@ bool IsSame(Node* a, Node* b) {
 bool NeedsConvertReceiver(Node* receiver, Node* effect) {
   for (Node* dominator = effect;;) {
     if (dominator->opcode() == IrOpcode::kCheckMaps &&
-        IsSame(dominator->InputAt(0), receiver)) {
+        NodeProperties::IsSame(dominator->InputAt(0), receiver)) {
       // Check if all maps have the given {instance_type}.
       ZoneHandleSet<Map> const& maps =
           CheckMapsParametersOf(dominator->op()).maps();

src/compiler/node-properties.cc

@@ -312,6 +312,20 @@ void NodeProperties::CollectControlProjections(Node* node, Node** projections,
 #endif
 }
 
+// static
+bool NodeProperties::IsSame(Node* a, Node* b) {
+  for (;;) {
+    if (a->opcode() == IrOpcode::kCheckHeapObject) {
+      a = GetValueInput(a, 0);
+      continue;
+    }
+    if (b->opcode() == IrOpcode::kCheckHeapObject) {
+      b = GetValueInput(b, 0);
+      continue;
+    }
+    return a == b;
+  }
+}
 
 // static
 MaybeHandle<Context> NodeProperties::GetSpecializationContext(

src/compiler/node-properties.h

@@ -123,6 +123,9 @@ class V8_EXPORT_PRIVATE NodeProperties final {
   //  - Switch: [ IfValue, ..., IfDefault ]
   static void CollectControlProjections(Node* node, Node** proj, size_t count);
 
+  // Checks if two nodes are the same, looking past {CheckHeapObject}.
+  static bool IsSame(Node* a, Node* b);
+
   // ---------------------------------------------------------------------------
   // Context.