[turbofan] Added the RoundInt64ToFloat64 instruction to TurboFan.

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index c7d702d679c00ecd110223a59692fed162ea10c5..6360008587bed6a731a8baf5de5a995781b764e3 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -710,6 +710,8 @@ void InstructionSelector::VisitNode(Node* node) {
       return MarkAsWord32(node), VisitTruncateFloat64ToInt32(node);
     case IrOpcode::kTruncateInt64ToInt32:
       return MarkAsWord32(node), VisitTruncateInt64ToInt32(node);
+    case IrOpcode::kRoundInt64ToFloat64:
+      return MarkAsFloat64(node), VisitRoundInt64ToFloat64(node);
     case IrOpcode::kBitcastFloat32ToInt32:
       return MarkAsWord32(node), VisitBitcastFloat32ToInt32(node);
     case IrOpcode::kBitcastFloat64ToInt64:
@@ -924,6 +926,11 @@ void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
 }
 
 
+void InstructionSelector::VisitRoundInt64ToFloat64(Node* node) {
+  UNIMPLEMENTED();
+}
+
+
 void InstructionSelector::VisitBitcastFloat64ToInt64(Node* node) {
   UNIMPLEMENTED();
 }