Add Float64Round operator.

src/compiler/machine-operator.cc

Index: src/compiler/machine-operator.cc
diff --git a/src/compiler/machine-operator.cc b/src/compiler/machine-operator.cc
index b5da8297e1d2c62e73d06866f50d8eaa489ea071..33ada6e92274c121c5ee0e00e7e9b3699c86fef0 100644
--- a/src/compiler/machine-operator.cc
+++ b/src/compiler/machine-operator.cc
@@ -181,6 +181,22 @@ struct MachineOperatorBuilderImpl {
   Store##Type##FullWriteBarrier##Operator k##Store##Type##FullWriteBarrier;
   MACHINE_TYPE_LIST(STORE)
 #undef STORE
+
+  struct Float64RoundOperator FINAL : public Operator1<Float64RoundMode> {
+    explicit Float64RoundOperator(Float64RoundMode mode)
+        : Operator1(IrOpcode::kFloat64Round, Operator::kPure, 1, 1,
+                    "Float64Round", mode) {}
+  };
+  Float64RoundOperator kFloat64RoundDown;
+  Float64RoundOperator kFloat64RoundUp;
+  Float64RoundOperator kFloat64RoundAway;
+  Float64RoundOperator kFloat64RoundTowards;
+
+  MachineOperatorBuilderImpl()
+      : kFloat64RoundDown(kRoundDown),
+        kFloat64RoundUp(kRoundUp),
+        kFloat64RoundAway(kRoundAway),
+        kFloat64RoundTowards(kRoundTowards) {}
 };
 
 
@@ -188,8 +204,9 @@ static base::LazyInstance<MachineOperatorBuilderImpl>::type kImpl =
     LAZY_INSTANCE_INITIALIZER;
 
 
-MachineOperatorBuilder::MachineOperatorBuilder(MachineType word)
-    : impl_(kImpl.Get()), word_(word) {
+MachineOperatorBuilder::MachineOperatorBuilder(
+    MachineType word, SupportedOperators supportedOperators)
+    : impl_(kImpl.Get()), word_(word), supportedOperators_(supportedOperators) {
   DCHECK(word == kRepWord32 || word == kRepWord64);
 }
 
@@ -237,6 +254,25 @@ const Operator* MachineOperatorBuilder::Store(StoreRepresentation rep) {
   return NULL;
 }
 
+
+const Operator* MachineOperatorBuilder::Float64Round(Float64RoundMode mode) {
+  switch (mode) {
+    case kRoundDown:
+      DCHECK(HasFloat64Floor());
+      return &impl_.kFloat64RoundDown;
+    case kRoundUp:
+      DCHECK(HasFloat64Ceil());
+      return &impl_.kFloat64RoundUp;
+    case kRoundAway:
+      DCHECK(HasFloat64RoundTiesAway());
+      return &impl_.kFloat64RoundAway;
+    case kRoundTowards:
+      DCHECK(HasFloat64RoundTiesTowards());
+      return &impl_.kFloat64RoundTowards;
+  }
+  UNREACHABLE();
+  return NULL;
+}
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8