https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85939
--- Comment #7 from Florian Weimer <fw at gcc dot gnu.org> --- (In reply to H.J. Lu from comment #6) > I believe __m64 is 4-byte aligned. https://github.com/hjl-tools/x86-psABI/blob/801352a1470ae8542a3a1f83fb2abda35feab075/low-level-sys-info.tex#L108 says alignment is 8 bytes. Is it a bug in the ABI document?