https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107412
--- Comment #3 from Kewen Lin <linkw at gcc dot gnu.org> --- (In reply to Segher Boessenkool from comment #2) > Make sure we only use "plain" accesses on machines that allow all unaligned > accesses? p8 and later I think. The load-with-length insns are even later, > but a builtin does not necessarily translate to those newer insns, so some > care is required :-) Thanks for raising this, for now these LEN_{LOAD,STORE} can ONLY be generated when the target defines the relevant optab len_{load,store}, on power it's power9 and later, while on s390 it should be some latest cpu I guess. Those are internal function and invisible for users, the support and the documentation assume it can work for unaligned access, if some target wants to emulate it later, it needs some more updates (not only this folding). So we don't need to bother it for now IHMO. :)