Index: llvm/lib/Target/AVR/MCTargetDesc/AVRInstPrinter.cpp
===================================================================
--- llvm/lib/Target/AVR/MCTargetDesc/AVRInstPrinter.cpp
+++ llvm/lib/Target/AVR/MCTargetDesc/AVRInstPrinter.cpp
@@ -100,6 +100,11 @@
 
 void AVRInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
                                   raw_ostream &O) {
+  if (OpNo >= MI->size()) {
+    O << "<unknown>";
+    return;
+  }
+
   const MCOperand &Op = MI->getOperand(OpNo);
   const MCOperandInfo &MOI = this->MII.get(MI->getOpcode()).OpInfo[OpNo];
 
@@ -125,6 +130,11 @@
 /// being encoded as a pc-relative value.
 void AVRInstPrinter::printPCRelImm(const MCInst *MI, unsigned OpNo,
                                    raw_ostream &O) {
+  if (OpNo >= MI->size()) {
+    O << "<unknown>";
+    return;
+  }
+
   const MCOperand &Op = MI->getOperand(OpNo);
 
   if (Op.isImm()) {