[turbofan] Added the optional Float64RoundTiesEven operator to turbofan.

src/compiler/arm/instruction-selector-arm.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/base/adapters.h"
 #include "src/base/bits.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 1117 matching lines @@
 void InstructionSelector::VisitFloat64RoundTruncate(Node* node) {
   VisitRR(this, kArmVrintzF64, node);
 }
 
 
 void InstructionSelector::VisitFloat64RoundTiesAway(Node* node) {
   VisitRR(this, kArmVrintaF64, node);
 }
 
 
+void InstructionSelector::VisitFloat64RoundTiesEven(Node* node) {
+  VisitRR(this, kArmVrintnF64, node);
+}
+
+
 void InstructionSelector::EmitPrepareArguments(NodeVector* arguments,
                                                const CallDescriptor* descriptor,
                                                Node* node) {
   ArmOperandGenerator g(this);
 
   // Prepare for C function call.
   if (descriptor->IsCFunctionCall()) {
     Emit(kArchPrepareCallCFunction |
              MiscField::encode(static_cast<int>(descriptor->CParameterCount())),
          0, nullptr, 0, nullptr);
@@ skipping 408 matching lines @@
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   MachineOperatorBuilder::Flags flags =
       MachineOperatorBuilder::kInt32DivIsSafe |
       MachineOperatorBuilder::kUint32DivIsSafe;
   if (CpuFeatures::IsSupported(ARMv8)) {
     flags |= MachineOperatorBuilder::kFloat64RoundDown |
              MachineOperatorBuilder::kFloat64RoundUp |
              MachineOperatorBuilder::kFloat64RoundTruncate |
-             MachineOperatorBuilder::kFloat64RoundTiesAway;
+             MachineOperatorBuilder::kFloat64RoundTiesAway |
+             MachineOperatorBuilder::kFloat64RoundTiesEven;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8