[turbofan] Implemented the TruncateFloat64ToUint64 TurboFan operator.

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

Index: test/cctest/compiler/test-run-machops.cc
diff --git a/test/cctest/compiler/test-run-machops.cc b/test/cctest/compiler/test-run-machops.cc
index c6ed018a3a8705e17f92f3b501b6322fc5a1de66..2268ac5371a50a4b66c4b443213967143ec05385 100644
--- a/test/cctest/compiler/test-run-machops.cc
+++ b/test/cctest/compiler/test-run-machops.cc
@@ -5364,6 +5364,26 @@ TEST(RunChangeFloat64ToInt64) {
 }
 
 
+TEST(RunTruncateFloat64ToUint64) {
+  BufferedRawMachineAssemblerTester<uint64_t> m(kMachFloat64);
+  m.Return(m.TruncateFloat64ToUint64(m.Parameter(0)));
+
+  FOR_UINT64_INPUTS(j) {
+    double input = static_cast<double>(*j);
+
+    if (input < 18446744073709551616.0) {
+      CHECK_EQ(static_cast<uint64_t>(input), m.Call(input));
+    }
+  }
+
+  FOR_FLOAT64_INPUTS(i) {
+    if (*i < 18446744073709551616.0 && *i >= 0) {
+      CHECK_EQ(static_cast<uint64_t>(*i), m.Call(*i));
+    }
+  }
+}
+
+
 TEST(RunRoundInt64ToFloat32) {
   BufferedRawMachineAssemblerTester<float> m(kMachInt64);
   m.Return(m.RoundInt64ToFloat32(m.Parameter(0)));