To avoid printing out multiple error messages for cases like:

.long 80+08

go ahead and assume that if we've got an Error token that we handled it
already. Otherwise if it's a token we can't handle then go ahead and
return the default error.

llvm-svn: 129322

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -539,6 +539,9 @@ bool AsmParser::ParsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
   switch (Lexer.getKind()) {
   default:
     return TokError("unknown token in expression");
+  // If we have an error assume that we've already handled it.
+  case AsmToken::Error:
+    return true;
   case AsmToken::Exclaim:
     Lex(); // Eat the operator.
     if (ParsePrimaryExpr(Res, EndLoc))