https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91198
--- Comment #1 from Andrew Stubbs <ams at gcc dot gnu.org> --- I don't believe GCC detects that operation automatically. It does support the instruction via intrinsics (builtin functions that correspond to low-level machine features). You should investigate "__builtin_ia32_compressstoresf512_mask" and friends.
