[turbofan] Avoid introducing useless JSConvertReceiver during inlining.

src/compiler/js-inlining.cc

 // Copyright 2014 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-inlining.h"
 
 #include "src/ast/ast.h"
 #include "src/compilation-info.h"
 #include "src/compiler.h"
 #include "src/compiler/all-nodes.h"
@@ skipping 272 matching lines @@
 // map tracking we want to do, and eventually changed the CheckMaps
 // operator to carry map constants on the operator instead of inputs.
 // I.e. if the CheckMaps has some kind of SmallMapSet as operator
 // parameter, then this could be changed to call a generic
 //
 //   SmallMapSet NodeProperties::CollectMapWitness(receiver, effect)
 //
 // function, which either returns the map set from the CheckMaps or
 // a singleton set from a StoreField.
 bool NeedsConvertReceiver(Node* receiver, Node* effect) {
+  // Check if the {receiver} is already a JSReceiver.
+  switch (receiver->opcode()) {
+    case IrOpcode::kJSConstruct:
+    case IrOpcode::kJSConstructWithSpread:
+    case IrOpcode::kJSCreate:
+    case IrOpcode::kJSCreateArguments:
+    case IrOpcode::kJSCreateArray:
+    case IrOpcode::kJSCreateClosure:
+    case IrOpcode::kJSCreateIterResultObject:
+    case IrOpcode::kJSCreateKeyValueArray:
+    case IrOpcode::kJSCreateLiteralArray:
+    case IrOpcode::kJSCreateLiteralObject:
+    case IrOpcode::kJSCreateLiteralRegExp:
+    case IrOpcode::kJSConvertReceiver:
+    case IrOpcode::kJSGetSuperConstructor:
+    case IrOpcode::kJSToObject:
+      return false;
+    default:
+      break;
+  }
+  if (receiver->opcode() == IrOpcode::kJSCreate) return false;

[Jarin, 2017/02/17 10:07:46]

This line is not necessary anymore, no?

[Benedikt Meurer, 2017/02/17 10:09:40]

Done.

   for (Node* dominator = effect;;) {
     if (dominator->opcode() == IrOpcode::kCheckMaps &&
         NodeProperties::IsSame(dominator->InputAt(0), receiver)) {
       // Check if all maps have the given {instance_type}.
       ZoneHandleSet<Map> const& maps =
           CheckMapsParametersOf(dominator->op()).maps();
       for (size_t i = 0; i < maps.size(); ++i) {
         if (!maps[i]->IsJSReceiverMap()) return true;
       }
       return false;
@@ skipping 432 matching lines @@
 
 CommonOperatorBuilder* JSInliner::common() const { return jsgraph()->common(); }
 
 SimplifiedOperatorBuilder* JSInliner::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8