Implemented the RoundUint64ToFloat64 TurboFan operator for x64 and arm64.

test/cctest/compiler/test-run-machops.cc

 // Copyright 2014 the V8 project authors. All rights reserved. Use of this
 // source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 
 // TODO(jochen): Remove this after the setting is turned on globally.
 #define V8_IMMINENT_DEPRECATION_WARNINGS
 
 #include <cmath>
 #include <functional>
 #include <limits>
@@ skipping 5363 matching lines @@
 }
 
 
 TEST(RunRoundInt64ToFloat64) {
   BufferedRawMachineAssemblerTester<double> m(kMachInt64);
   m.Return(m.RoundInt64ToFloat64(m.Parameter(0)));
   FOR_INT64_INPUTS(i) { CHECK_EQ(static_cast<double>(*i), m.Call(*i)); }
 }
 
 
+TEST(RunRoundUint64ToFloat64) {
+  BufferedRawMachineAssemblerTester<double> m(kMachUint64);
+  m.Return(m.RoundUint64ToFloat64(m.Parameter(0)));
+  FOR_UINT64_INPUTS(i) { CHECK_EQ(static_cast<double>(*i), m.Call(*i)); }
+}
+
+
 #endif
 
 
 TEST(RunBitcastFloat32ToInt32) {
   float input = 32.25;
   RawMachineAssemblerTester<int32_t> m;
   m.Return(m.BitcastFloat32ToInt32(m.LoadFromPointer(&input, kMachFloat32)));
   FOR_FLOAT32_INPUTS(i) {
     input = *i;
     int32_t expected = bit_cast<int32_t>(input);
@@ skipping 65 matching lines @@
   Node* call = r.AddNode(r.common()->Call(desc), phi);
   r.Return(call);
 
   CHECK_EQ(33, r.Call(1));
   CHECK_EQ(44, r.Call(0));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8