[turbofan] Remove the TryLowerDirectJSCall hack from generic lowering.

src/compiler/js-generic-lowering.cc

Index: src/compiler/js-generic-lowering.cc
diff --git a/src/compiler/js-generic-lowering.cc b/src/compiler/js-generic-lowering.cc
index 322654cad57371f7f5f49dc39af36d8a768b1f1a..51b4f10073f673f079d891b313be8e13a435f9bf 100644
--- a/src/compiler/js-generic-lowering.cc
+++ b/src/compiler/js-generic-lowering.cc
@@ -514,44 +514,7 @@ void JSGenericLowering::LowerJSCallConstruct(Node* node) {
 }
 
 
-bool JSGenericLowering::TryLowerDirectJSCall(Node* node) {
-  // Lower to a direct call to a constant JSFunction if legal.
-  const CallFunctionParameters& p = CallFunctionParametersOf(node->op());
-  int arg_count = static_cast<int>(p.arity() - 2);
-
-  // Check the function is a constant and is really a JSFunction.
-  HeapObjectMatcher<Object> function_const(node->InputAt(0));
-  if (!function_const.HasValue()) return false;  // not a constant.
-  Handle<Object> func = function_const.Value().handle();
-  if (!func->IsJSFunction()) return false;  // not a function.
-  Handle<JSFunction> function = Handle<JSFunction>::cast(func);
-  if (arg_count != function->shared()->internal_formal_parameter_count()) {
-    return false;
-  }
-
-  // Check the receiver doesn't need to be wrapped.
-  Node* receiver = node->InputAt(1);
-  if (!NodeProperties::IsTyped(receiver)) return false;
-  Type* ok_receiver = Type::Union(Type::Undefined(), Type::Receiver(), zone());
-  if (!NodeProperties::GetBounds(receiver).upper->Is(ok_receiver)) return false;
-
-  // Update to the function context.
-  NodeProperties::ReplaceContextInput(
-      node, jsgraph()->HeapConstant(Handle<Context>(function->context())));
-  CallDescriptor::Flags flags = FlagsForNode(node);
-  if (is_strict(p.language_mode())) flags |= CallDescriptor::kSupportsTailCalls;
-  CallDescriptor* desc =
-      Linkage::GetJSCallDescriptor(zone(), false, 1 + arg_count, flags);
-  node->set_op(common()->Call(desc));
-  return true;
-}
-
-
 void JSGenericLowering::LowerJSCallFunction(Node* node) {
-  // Fast case: call function directly.
-  if (TryLowerDirectJSCall(node)) return;
-
-  // General case: CallFunctionStub.
   const CallFunctionParameters& p = CallFunctionParametersOf(node->op());
   int arg_count = static_cast<int>(p.arity() - 2);
   CallFunctionStub stub(isolate(), arg_count, p.flags());