[turbofan] Added the optional Float64RoundTiesEven operator to turbofan.

src/compiler/mips64/instruction-selector-mips64.cc

Index: src/compiler/mips64/instruction-selector-mips64.cc
diff --git a/src/compiler/mips64/instruction-selector-mips64.cc b/src/compiler/mips64/instruction-selector-mips64.cc
index eae1d3f39dbcd12e68ba942af5f7f729d0d0b41e..4f5eebf1a764ae0a7b077ca0fbd994ed35dd88af 100644
--- a/src/compiler/mips64/instruction-selector-mips64.cc
+++ b/src/compiler/mips64/instruction-selector-mips64.cc
@@ -817,6 +817,11 @@ void InstructionSelector::VisitFloat64RoundTiesAway(Node* node) {
 }
 
 
+void InstructionSelector::VisitFloat64RoundTiesEven(Node* node) {
+  VisitRR(this, kMips64Float64RoundTiesEven, node);
+}
+
+
 void InstructionSelector::EmitPrepareArguments(NodeVector* arguments,
                                                const CallDescriptor* descriptor,
                                                Node* node) {
@@ -1398,7 +1403,8 @@ InstructionSelector::SupportedMachineOperatorFlags() {
          MachineOperatorBuilder::kFloat32Max |
          MachineOperatorBuilder::kFloat64RoundDown |
          MachineOperatorBuilder::kFloat64RoundUp |
-         MachineOperatorBuilder::kFloat64RoundTruncate;
+         MachineOperatorBuilder::kFloat64RoundTruncate |
+         MachineOperatorBuilder::kFloat64RoundTiesEven;
 }
 
 }  // namespace compiler