Be crazy and assert in case of unsupported modifier passed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84712 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/MSP430/AsmPrinter/MSP430InstPrinter.cpp b/lib/Target/MSP430/AsmPrinter/MSP430InstPrinter.cpp
index 59b448a..8f1ee81 100644
--- a/lib/Target/MSP430/AsmPrinter/MSP430InstPrinter.cpp
+++ b/lib/Target/MSP430/AsmPrinter/MSP430InstPrinter.cpp
@@ -47,6 +47,7 @@
 
 void MSP430InstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
                                      const char *Modifier) {
+  assert((Modifier == 0 || Modifier[0] == 0) && "No modifiers supported");
   const MCOperand &Op = MI->getOperand(OpNo);
   if (Op.isReg()) {
     O << getRegisterName(Op.getReg());