https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77597
--- Comment #4 from Chris Green <greenc at fnal dot gov> --- (In reply to Jakub Jelinek from comment #3) > Ah, maybe I'm wrong what S6_ stands for. Anyway: > https://llvm.org/bugs/show_bug.cgi?id=30401#c1 > has more details. So NOTABUG? See particularly https://llvm.org/bugs/show_bug.cgi?id=30401#c1. While the c++filt provided with binutils on Ubuntu 16.04 demangles both symbols to the same (correct) function, LLVM's libc++abi demangler demonstrates an apparent erroneous backreference in LLVM's mangled symbol name. Until new evidence suggests otherwise, I'd be willing to accept a determination that this is LLVM's bug, not GCC's.