https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80833
--- Comment #12 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Peter Cordes from comment #4) > MMX is also a saving in code-size: one fewer prefix byte vs. SSE2 integer > instructions. It's also another set of 8 registers for 32-bit mode. After touching a MMX register, the compiler needs to emit emms insn, so MMX moves are practically unusable as generic moves.
