https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92684
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- bit-fields in C is a type. while in C++, it is not. So: st.v2 << 3 This is not ((long)st.v2) << 3 but rather (long:45)<<3. So it gets truncated. C11: ffff0000fff8 0xffff0000fff80000 1fff0000fff8 1 2 ffffffff80000000 C++14: ffff0000fff8 0xffff0000fff80000 ffff0000fff8 1 2 ffffffff80000000
