https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112891
--- Comment #4 from Richard Sandiford <rsandifo at gcc dot gnu.org> --- (In reply to Hongtao Liu from comment #2) > So it looks like we need to handle ix86_avx_u128_mode_after > > --- a/gcc/config/i386/i386.cc > +++ b/gcc/config/i386/i386.cc > @@ -15177,7 +15177,14 @@ ix86_avx_u128_mode_after (int mode, rtx_insn *insn) > bool avx_upper_reg_found = false; > note_stores (insn, ix86_check_avx_upper_stores, &avx_upper_reg_found); > > - return avx_upper_reg_found ? AVX_U128_DIRTY : AVX_U128_CLEAN; > + if (avx_upper_reg_found) > + return AVX_U128_DIRTY; > + > + const function_abi &abi = insn_callee_abi (insn); > + if (!hard_reg_set_subset_p (reg_class_contents[SSE_REGS], > + abi.mode_clobbers (V4DImode))) > + return AVX_U128_ANY; > + return AVX_U128_CLEAN; > } It's a long time since I looked at this code, but this looks correct to me FWIW.
