[turbofan] Optimize ToName conversion.

src/compiler/js-typed-lowering.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-typed-lowering.h"
 
 #include "src/ast/modules.h"
 #include "src/builtins/builtins-utils.h"
 #include "src/code-factory.h"
 #include "src/compilation-dependencies.h"
@@ skipping 967 matching lines @@
   Node* const input = NodeProperties::GetValueInput(node, 0);
   Type* const input_type = NodeProperties::GetType(input);
   if (input_type->Is(type_cache_.kIntegerOrMinusZero)) {
     // JSToInteger(x:integer) => x
     ReplaceWithValue(node, input);
     return Replace(input);
   }
   return NoChange();
 }
 
+Reduction JSTypedLowering::ReduceJSToName(Node* node) {
+  Node* const input = NodeProperties::GetValueInput(node, 0);
+  Type* const input_type = NodeProperties::GetType(input);
+  if (input_type->Is(Type::Name())) {
+    // JSToName(x:name) => x
+    ReplaceWithValue(node, input);
+    return Replace(input);
+  }
+  return NoChange();
+}
+
 Reduction JSTypedLowering::ReduceJSToLength(Node* node) {
   Node* input = NodeProperties::GetValueInput(node, 0);
   Type* input_type = NodeProperties::GetType(input);
   if (input_type->Is(type_cache_.kIntegerOrMinusZero)) {
     if (input_type->Max() <= 0.0) {
       input = jsgraph()->ZeroConstant();
     } else if (input_type->Min() >= kMaxSafeInteger) {
       input = jsgraph()->Constant(kMaxSafeInteger);
     } else {
       if (input_type->Min() <= 0.0) {
@@ skipping 1188 matching lines @@
     case IrOpcode::kJSMultiply:
     case IrOpcode::kJSDivide:
     case IrOpcode::kJSModulus:
       return ReduceNumberBinop(node);
     case IrOpcode::kJSToBoolean:
       return ReduceJSToBoolean(node);
     case IrOpcode::kJSToInteger:
       return ReduceJSToInteger(node);
     case IrOpcode::kJSToLength:
       return ReduceJSToLength(node);
+    case IrOpcode::kJSToName:
+      return ReduceJSToName(node);
     case IrOpcode::kJSToNumber:
       return ReduceJSToNumber(node);
     case IrOpcode::kJSToString:
       return ReduceJSToString(node);
     case IrOpcode::kJSToObject:
       return ReduceJSToObject(node);
     case IrOpcode::kJSTypeOf:
       return ReduceJSTypeOf(node);
     case IrOpcode::kJSLoadNamed:
       return ReduceJSLoadNamed(node);
@@ skipping 55 matching lines @@
 }
 
 
 CompilationDependencies* JSTypedLowering::dependencies() const {
   return dependencies_;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8