Fix crash while printing MMO target flags

[rampitec]

Summary

MachineMemOperand::print can dereference a NULL pointer if TII
is not passed from the printMemOperand. This does not happen while
dumping the DAG/MIR from llc but crashes the debugger if a dump()
method is called from gdb.

llvm/lib/CodeGen/MachineOperand.cpp

void MachineMemOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
   if (isVolatile())
     OS << "volatile ";
   if (isNonTemporal())
     OS << "non-temporal ";
   if (isDereferenceable())
     OS << "dereferenceable ";
   if (isInvariant())
     OS << "invariant ";
+  if (TII) {
     if (getFlags() & MachineMemOperand::MOTargetFlag1)
       OS << '"' << getTargetMMOFlagName(*TII, MachineMemOperand::MOTargetFlag1)
          << "\" ";
     if (getFlags() & MachineMemOperand::MOTargetFlag2)
       OS << '"' << getTargetMMOFlagName(*TII, MachineMemOperand::MOTargetFlag2)
          << "\" ";
     if (getFlags() & MachineMemOperand::MOTargetFlag3)
       OS << '"' << getTargetMMOFlagName(*TII, MachineMemOperand::MOTargetFlag3)
          << "\" ";
+  } else {
+    if (getFlags() & MachineMemOperand::MOTargetFlag1)
+      OS << "\"MOTargetFlag1\" ";
+    if (getFlags() & MachineMemOperand::MOTargetFlag2)
+      OS << "\"MOTargetFlag2\" ";
+    if (getFlags() & MachineMemOperand::MOTargetFlag3)
+      OS << "\"MOTargetFlag3\" ";
+  }
 
   assert((isLoad() || isStore()) &&
          "machine memory operand must be a load or store (or both)");
   if (isLoad())
     OS << "load ";
   if (isStore())
     OS << "store ";