PPC64: Implemented the RoundUint64ToFloat64 TurboFan operator.

src/compiler/ppc/code-generator-ppc.cc

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index 1d8d0dd1c5c3e9739ca0e46f1f4d4a4b66d65030..93b5a47f432559b5e35a1b9d0ed6a311cdc1c757 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -1095,6 +1095,11 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ ConvertInt64ToDouble(i.InputRegister(0), i.OutputDoubleRegister());
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
+    case kPPC_Uint64ToDouble:
+      __ ConvertUnsignedInt64ToDouble(i.InputRegister(0),
+                                      i.OutputDoubleRegister());
+      DCHECK_EQ(LeaveRC, i.OutputRCBit());
+      break;
 #endif
     case kPPC_Int32ToDouble:
       __ ConvertIntToDouble(i.InputRegister(0), i.OutputDoubleRegister());