https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88398
--- Comment #31 from Wilco <wilco at gcc dot gnu.org> --- (In reply to Jiu Fu Guo from comment #30) > (In reply to Wilco from comment #29) > > The key question remains whether it is legal to assume the limit implies the > > memory is valid and use wider accesses. > If unaligned access is support, it would be valid to access the memory. > Otherwise, checking like ((pb&7) == (cur & 7)) would cost an additional > test, and it may not sure likely to be true. If both pointers are aligned it would be safe indeed, but if unaligned they will access up to 7 bytes after the first match. And that's not safe without knowing the underlying buffer bounds. See eg. comment #3.
