[turbofan] Added the optional Float64RoundTiesEven operator to turbofan.

src/compiler/ia32/instruction-selector-ia32.cc

Index: src/compiler/ia32/instruction-selector-ia32.cc
diff --git a/src/compiler/ia32/instruction-selector-ia32.cc b/src/compiler/ia32/instruction-selector-ia32.cc
index 40167a472cc54ec5828e30c4abae2b05fdaea8e6..fd976bc3b3ac3bd851acc79a2b3d8912ae6878bc 100644
--- a/src/compiler/ia32/instruction-selector-ia32.cc
+++ b/src/compiler/ia32/instruction-selector-ia32.cc
@@ -871,6 +871,11 @@ void InstructionSelector::VisitFloat64RoundTiesAway(Node* node) {
 }
 
 
+void InstructionSelector::VisitFloat64RoundTiesEven(Node* node) {
+  VisitRR(this, node, kSSEFloat64Round | MiscField::encode(kRoundToNearest));
+}
+
+
 void InstructionSelector::EmitPrepareArguments(NodeVector* arguments,
                                                const CallDescriptor* descriptor,
                                                Node* node) {
@@ -1281,7 +1286,8 @@ InstructionSelector::SupportedMachineOperatorFlags() {
   if (CpuFeatures::IsSupported(SSE4_1)) {
     flags |= MachineOperatorBuilder::kFloat64RoundDown |
              MachineOperatorBuilder::kFloat64RoundUp |
-             MachineOperatorBuilder::kFloat64RoundTruncate;
+             MachineOperatorBuilder::kFloat64RoundTruncate |
+             MachineOperatorBuilder::kFloat64RoundTiesEven;
   }
   return flags;
 }