https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102865
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2021-10-21 Status|UNCONFIRMED |WAITING Ever confirmed|0 |1 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- HFmode should be supported: static bool ix86_scalar_mode_supported_p (scalar_mode mode) { if (DECIMAL_FLOAT_MODE_P (mode)) return default_decimal_float_supported_p (); else if (mode == TFmode) return true; else if (mode == HFmode && TARGET_SSE2) return true; else return default_scalar_mode_supported_p (mode); } SSE2 is default on for x86_64. Are you sure that the first compiler is not miscompiling the new one?