[turbofan] Inline Array.isArray in JSBuiltinReducer.

src/compiler/js-builtin-reducer.cc

Index: src/compiler/js-builtin-reducer.cc
diff --git a/src/compiler/js-builtin-reducer.cc b/src/compiler/js-builtin-reducer.cc
index a9af93c80ce9cb6e661d72ab5ff189ca6aa49884..e3bafadaef0ef1304680fa9553d4617000e3a57c 100644
--- a/src/compiler/js-builtin-reducer.cc
+++ b/src/compiler/js-builtin-reducer.cc
@@ -725,6 +725,104 @@ Reduction JSBuiltinReducer::ReduceArrayIteratorNext(Node* node) {
   return NoChange();
 }
 
+// ES6 section 22.1.2.2 Array.isArray ( arg )
+Reduction JSBuiltinReducer::ReduceArrayIsArray(Node* node) {
+  // We certainly know that undefined is not an array.
+  if (node->op()->ValueInputCount() < 3) {
+    Node* value = jsgraph()->FalseConstant();
+    ReplaceWithValue(node, value);
+    return Replace(value);
+  }
+  Node* value = NodeProperties::GetValueInput(node, 2);
+  Node* context = NodeProperties::GetContextInput(node);
+  Node* frame_state = NodeProperties::GetFrameStateInput(node);
+  Node* effect = NodeProperties::GetEffectInput(node);
+  Node* control = NodeProperties::GetControlInput(node);
+
+  int count = 0;
+  Node* values[5];
+  Node* effects[5];
+  Node* controls[4];
+
+  // Check if the {value} is a Smi.
+  Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), value);
+  control =
+      graph()->NewNode(common()->Branch(BranchHint::kFalse), check, control);
+
+  // The {value} is a Smi.
+  controls[count] = graph()->NewNode(common()->IfTrue(), control);
+  effects[count] = effect;
+  values[count] = jsgraph()->FalseConstant();
+  count++;
+
+  control = graph()->NewNode(common()->IfFalse(), control);
+
+  // Load the {value}s instance type.
+  Node* value_map = effect = graph()->NewNode(
+      simplified()->LoadField(AccessBuilder::ForMap()), value, effect, control);
+  Node* value_instance_type = effect = graph()->NewNode(
+      simplified()->LoadField(AccessBuilder::ForMapInstanceType()), value_map,
+      effect, control);
+
+  // Check if the {value} is a JSArray.
+  check = graph()->NewNode(simplified()->NumberEqual(), value_instance_type,
+                           jsgraph()->Constant(JS_ARRAY_TYPE));
+  control = graph()->NewNode(common()->Branch(), check, control);
+
+  // The {value} is a JSArray.
+  controls[count] = graph()->NewNode(common()->IfTrue(), control);
+  effects[count] = effect;
+  values[count] = jsgraph()->TrueConstant();
+  count++;
+
+  control = graph()->NewNode(common()->IfFalse(), control);
+
+  // Check if the {value} is a JSProxy.
+  check = graph()->NewNode(simplified()->NumberEqual(), value_instance_type,
+                           jsgraph()->Constant(JS_PROXY_TYPE));
+  control =
+      graph()->NewNode(common()->Branch(BranchHint::kFalse), check, control);
+
+  // The {value} is neither a JSArray nor a JSProxy.
+  controls[count] = graph()->NewNode(common()->IfFalse(), control);
+  effects[count] = effect;
+  values[count] = jsgraph()->FalseConstant();
+  count++;
+
+  control = graph()->NewNode(common()->IfTrue(), control);
+
+  // Let the %ArrayIsArray runtime function deal with the JSProxy {value}.
+  value = effect =
+      graph()->NewNode(javascript()->CallRuntime(Runtime::kArrayIsArray), value,
+                       context, frame_state, effect, control);
+  NodeProperties::SetType(value, Type::Boolean());
+  control = graph()->NewNode(common()->IfSuccess(), value);
+
+  // Rewire any IfException edges on {node} to {value}.
+  for (Edge edge : node->use_edges()) {
+    Node* const user = edge.from();
+    if (user->opcode() == IrOpcode::kIfException) {
+      edge.UpdateTo(value);
+      Revisit(user);
+    }
+  }
+
+  // The {value} is neither a JSArray nor a JSProxy.
+  controls[count] = control;
+  effects[count] = effect;
+  values[count] = value;
+  count++;
+
+  control = graph()->NewNode(common()->Merge(count), count, controls);
+  effects[count] = control;
+  values[count] = control;
+  effect = graph()->NewNode(common()->EffectPhi(count), count + 1, effects);
+  value = graph()->NewNode(common()->Phi(MachineRepresentation::kTagged, count),
+                           count + 1, values);
+  ReplaceWithValue(node, value, effect, control);
+  return Replace(value);
+}
+
 // ES6 section 22.1.3.17 Array.prototype.pop ( )
 Reduction JSBuiltinReducer::ReduceArrayPop(Node* node) {
   Handle<Map> receiver_map;
@@ -1969,6 +2067,8 @@ Reduction JSBuiltinReducer::Reduce(Node* node) {
       return ReduceArrayIterator(node, IterationKind::kValues);
     case kArrayIteratorNext:
       return ReduceArrayIteratorNext(node);
+    case kArrayIsArray:
+      return ReduceArrayIsArray(node);
     case kArrayPop:
       return ReduceArrayPop(node);
     case kArrayPush: