https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79514
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to Uroš Bizjak from comment #6) > (In reply to Uroš Bizjak from comment #5) > > Maybe we should use our own pushxf expander? > > No. Middle end should be fixed. x86 does not define any of HAVE_PRE_MODIFY > macros. So what it can emit? PRE_DEC is not really right, because GET_MODE_SIZE (XFmode) is in that case 12, but PUSH_ROUNDING increases that to 16. But the push actually needs to adjust sp by 16, not 12. With -m128bit-long-double, rounded_size is equal to GET_MODE_SIZE and we get to: 4124 if (GET_MODE_SIZE (mode) == rounded_size) 4125 dest_addr = gen_rtx_fmt_e (STACK_PUSH_CODE, Pmode, stack_pointer_rtx); I think i386.md should have a pushxf1 expander enabled at least for the case when GET_MODE_SIZE (XFmode) != PUSH_ROUNDING (GET_MODE_SIZE (XFmode)) and just not use PRE_DEC in the pattern at all, just sp subtraction plus store.
