[turbofan] Slighly improve JSCreateArguments lowering.

src/compiler/js-create-lowering.cc

 // Copyright 2016 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-create-lowering.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
@@ skipping 275 matching lines @@
   // arguments object, but only for non-inlined (i.e. outermost) frames.
   if (outer_state->opcode() != IrOpcode::kFrameState) {
     switch (type) {
       case CreateArgumentsType::kMappedArguments: {
         // TODO(mstarzinger): Duplicate parameters are not handled yet.
         Handle<SharedFunctionInfo> shared_info;
         if (!state_info.shared_info().ToHandle(&shared_info) ||
             shared_info->has_duplicate_parameters()) {
           return NoChange();
         }
-        // TODO(bmeurer): Actually we don't need a frame state here.
         Callable callable = CodeFactory::FastNewSloppyArguments(isolate());
         CallDescriptor* desc = Linkage::GetStubCallDescriptor(
             isolate(), graph()->zone(), callable.descriptor(), 0,
-            CallDescriptor::kNeedsFrameState);
+            CallDescriptor::kNoFlags);
         const Operator* new_op = common()->Call(desc);
         Node* stub_code = jsgraph()->HeapConstant(callable.code());
         node->InsertInput(graph()->zone(), 0, stub_code);
+        node->RemoveInput(3);

[Jarin, 2016/05/11 04:45:27]

Could you say in the comment that you are removing frame state? (Here and
below.)

[Benedikt Meurer, 2016/05/11 05:37:48]

Done.

         NodeProperties::ChangeOp(node, new_op);
         return Changed(node);
       }
       case CreateArgumentsType::kUnmappedArguments: {
-        // TODO(bmeurer): Actually we don't need a frame state here.
         Callable callable = CodeFactory::FastNewStrictArguments(isolate());
         CallDescriptor* desc = Linkage::GetStubCallDescriptor(
             isolate(), graph()->zone(), callable.descriptor(), 0,
-            CallDescriptor::kNeedsFrameState);
+            CallDescriptor::kNoFlags);
         const Operator* new_op = common()->Call(desc);
         Node* stub_code = jsgraph()->HeapConstant(callable.code());
         node->InsertInput(graph()->zone(), 0, stub_code);
+        node->RemoveInput(3);
         NodeProperties::ChangeOp(node, new_op);
         return Changed(node);
       }
       case CreateArgumentsType::kRestParameter: {
-        // TODO(bmeurer): Actually we don't need a frame state here.
         Callable callable = CodeFactory::FastNewRestParameter(isolate());
         CallDescriptor* desc = Linkage::GetStubCallDescriptor(
             isolate(), graph()->zone(), callable.descriptor(), 0,
-            CallDescriptor::kNeedsFrameState);
+            CallDescriptor::kNoFlags);
         const Operator* new_op = common()->Call(desc);
         Node* stub_code = jsgraph()->HeapConstant(callable.code());
         node->InsertInput(graph()->zone(), 0, stub_code);
+        node->RemoveInput(3);
         NodeProperties::ChangeOp(node, new_op);
         return Changed(node);
       }
     }
     UNREACHABLE();
   } else if (outer_state->opcode() == IrOpcode::kFrameState) {
     // Use inline allocation for all mapped arguments objects within inlined
     // (i.e. non-outermost) frames, independent of the object size.
     if (type == CreateArgumentsType::kMappedArguments) {
       Handle<SharedFunctionInfo> shared;
@@ skipping 792 matching lines @@
   return jsgraph()->simplified();
 }
 
 MachineOperatorBuilder* JSCreateLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8