https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114505
--- Comment #13 from Andrew Pinski <pinskia at gcc dot gnu.org> --- I understand that this might be the reason why others have enabled zstd always but reading the code this case should be supported. That is LTO generated from a GCC without ZSTD support should be supported with one compiled with it. Plus: /* Compression algorithm used for compression of LTO bytecode. */ enum lto_compression { ZLIB, ZSTD }; ZSTD is 1 so it has to be something corrupting the field ...