[turbofan] Added the optional Float64RoundTiesEven operator to turbofan.

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index cf9cc4fc96bb121045e38d1b10dba148e1c44a9f..9da11b39f8442e244f3888c53309329d0faeadf9 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -119,18 +119,20 @@ class MachineOperatorBuilder final : public ZoneObject {
     kFloat64RoundDown = 1u << 4,
     kFloat64RoundUp = 1u << 5,
     kFloat64RoundTruncate = 1u << 6,
-    kFloat64RoundTiesAway = 1u << 7,
-    kInt32DivIsSafe = 1u << 8,
-    kUint32DivIsSafe = 1u << 9,
-    kWord32ShiftIsSafe = 1u << 10,
-    kWord32Ctz = 1u << 11,
-    kWord64Ctz = 1u << 12,
-    kWord32Popcnt = 1u << 13,
-    kWord64Popcnt = 1u << 14,
+    kFloat64RoundTiesEven = 1u << 7,
+    kFloat64RoundTiesAway = 1u << 8,
+    kInt32DivIsSafe = 1u << 9,
+    kUint32DivIsSafe = 1u << 10,
+    kWord32ShiftIsSafe = 1u << 11,
+    kWord32Ctz = 1u << 12,
+    kWord64Ctz = 1u << 13,
+    kWord32Popcnt = 1u << 14,
+    kWord64Popcnt = 1u << 15,
     kAllOptionalOps = kFloat32Max | kFloat32Min | kFloat64Max | kFloat64Min |
                       kFloat64RoundDown | kFloat64RoundUp |
                       kFloat64RoundTruncate | kFloat64RoundTiesAway |
-                      kWord32Ctz | kWord64Ctz | kWord32Popcnt | kWord64Popcnt
+                      kFloat64RoundTiesEven | kWord32Ctz | kWord64Ctz |
+                      kWord32Popcnt | kWord64Popcnt
   };
   typedef base::Flags<Flag, unsigned> Flags;
 
@@ -267,6 +269,7 @@ class MachineOperatorBuilder final : public ZoneObject {
   const OptionalOperator Float64RoundUp();
   const OptionalOperator Float64RoundTruncate();
   const OptionalOperator Float64RoundTiesAway();
+  const OptionalOperator Float64RoundTiesEven();
 
   // Floating point bit representation.
   const Operator* Float64ExtractLowWord32();