https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88409
--- Comment #5 from Nick Clifton <nickc at gcc dot gnu.org> --- (In reply to H.J. Lu from comment #4) > I am expecting that > > [hjl@gnu-cfl-1 libiberty]$ c++filt > _ZN4modc6parser8sequenceINS_9astParser13LocatedParserINS0_9ParserRefINS2_UlRN > S2_16TokenParserInputEE_EEEEEINS0_14OptionalParserINS2_18ListParserTemplateIL > NS_6tokens5Token4TypeE4EXadL_ZNSD_Ut_13parenthesizedEEEE6ParserINS4_INS0_6Par > serIS5_NS_3ast10ExpressionEEEEEEEEENSA_INS4_INS2_22OneOfKeywordsToTParserINSJ > _5StyleEEEEEEENS0_14SequenceParserIS5_INS0_18ExactElementParserIS5_EENSA_ISM_ > EEEEENS0_14RepeatedParserINS4_INS0_15TransformParserINSU_IS5_INS4_INSP_INSJ_1 > 0Annotation12RelationshipEEEEESX_EEENS2_UlNS2_3LocES12_ONS_5MaybeISK_EEE19_EE > EEELb0EEEEEENSU_INS0_17ExtractParserTypeIT_E9InputTypeEINS0_8MaybeRefIS1F_E4T > ypeEDpNS1I_IT0_E4TypeEEEEOS1F_DpOS1L_ > > continues to work. Does it work with your patch? No. But "c++filt -r <that-mangled-string>" will work. Is that string an example of a real world mangled symbol name, or was it just invented to test the demangler ?