PPC: [turbofan] Implemented the TruncateFloat64ToUint64 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 cf07caf6f3bc906faeadfe67a1a16b541f770f36..3d199a68ccbb0f0ace48ce833fcd2e1f698f95d8 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -1137,6 +1137,13 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
                               i.OutputRegister(), kScratchDoubleReg);
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
+#if V8_TARGET_ARCH_PPC64
+    case kPPC_DoubleToUint64:
+      __ ConvertDoubleToUnsignedInt64(i.InputDoubleRegister(0),
+                                      i.OutputRegister(), kScratchDoubleReg);
+      DCHECK_EQ(LeaveRC, i.OutputRCBit());
+      break;
+#endif
     case kPPC_DoubleToFloat32:
       ASSEMBLE_FLOAT_UNOP_RC(frsp);
       break;