Implemented the RoundInt64ToFloat32 TurboFan operator for x64, arm64, and mips64.

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 5a6088a193c8a169374f3a2974926435b9af26ec..b215714ed0753de3a9204f6914288b3b37e55e39 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -814,6 +814,8 @@ void InstructionSelector::VisitNode(Node* node) {
       return MarkAsWord32(node), VisitTruncateFloat64ToInt32(node);
     case IrOpcode::kTruncateInt64ToInt32:
       return MarkAsWord32(node), VisitTruncateInt64ToInt32(node);
+    case IrOpcode::kRoundInt64ToFloat32:
+      return MarkAsFloat32(node), VisitRoundInt64ToFloat32(node);
     case IrOpcode::kRoundInt64ToFloat64:
       return MarkAsFloat64(node), VisitRoundInt64ToFloat64(node);
     case IrOpcode::kBitcastFloat32ToInt32:
@@ -1036,6 +1038,11 @@ void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
 }
 
 
+void InstructionSelector::VisitRoundInt64ToFloat32(Node* node) {
+  UNIMPLEMENTED();
+}
+
+
 void InstructionSelector::VisitRoundInt64ToFloat64(Node* node) {
   UNIMPLEMENTED();
 }