[turbofan] Make an OptionalOperator for MachineOperatorBuilder.

test/unittests/compiler/raw-machine-assembler.h

 // 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.
 
 #ifndef V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 #define V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph-builder.h"
 #include "src/compiler/linkage.h"
@@ skipping 398 matching lines @@
   Node* TruncateFloat64ToFloat32(Node* a) {
     return NewNode(machine()->TruncateFloat64ToFloat32(), a);
   }
   Node* TruncateFloat64ToInt32(Node* a) {
     return NewNode(machine()->TruncateFloat64ToInt32(), a);
   }
   Node* TruncateInt64ToInt32(Node* a) {
     return NewNode(machine()->TruncateInt64ToInt32(), a);
   }
   Node* Float64RoundDown(Node* a) {
-    return NewNode(machine()->Float64RoundDown(), a);
+    return NewNode(machine()->Float64RoundDown().op(), a);
   }
   Node* Float64RoundTruncate(Node* a) {
-    return NewNode(machine()->Float64RoundTruncate(), a);
+    return NewNode(machine()->Float64RoundTruncate().op(), a);
   }
   Node* Float64RoundTiesAway(Node* a) {
-    return NewNode(machine()->Float64RoundTiesAway(), a);
+    return NewNode(machine()->Float64RoundTiesAway().op(), a);
   }
 
   // Float64 bit operations.
   Node* Float64ExtractLowWord32(Node* a) {
     return NewNode(machine()->Float64ExtractLowWord32(), a);
   }
   Node* Float64ExtractHighWord32(Node* a) {
     return NewNode(machine()->Float64ExtractHighWord32(), a);
   }
   Node* Float64InsertLowWord32(Node* a, Node* b) {
@@ skipping 78 matching lines @@
   BasicBlock* current_block_;
 
   DISALLOW_COPY_AND_ASSIGN(RawMachineAssembler);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_