https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94770
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to Bence Szabó from comment #4) > As a remark for 'same code with -std=c++14 and -std=c++17 here', I can > confirm, the example you provided also produces same assembly for me in > c++14 and c++17. > Also compiling t032 with only c++14 or only c++17 still results in a failing > test case (30.71) and then a crash. Maybe this is not the same abi problem? Ah, then it is not c++14 vs. c++17 ABI incompatibility, but some bug in va_arg passing of such classes for mingw.