Error on setting flag again

Author: optimisan

llvm/lib/CodeGen/MIRParser/MIRParser.cpp

@@ -703,6 +703,11 @@ bool MIRParserImpl::parseRegisterInfo(PerFunctionMIParsingState &PFS,
         return error(FlagStringValue.SourceRange.Start,
                      Twine("use of undefined register flag '") +
                          FlagStringValue.Value + "'");
+      if (Info.Flags & FlagValue)
+        return error(FlagStringValue.SourceRange.Start,
+                     Twine("flag '") + FlagStringValue.Value +
+                         "' was already set for virtual register '%" +
+                         Twine(VReg.ID.Value) + "'");
       Info.Flags |= FlagValue;
     }
     RegInfo.noteNewVirtualRegister(Info.VReg);