[Bug target/103571] ABI: V2HF, V4HF and V8HFmode argument passing issues

["ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103571

--- Comment #9 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Hongtao.liu from comment #8)
> (In reply to Uroš Bizjak from comment #6)
> > (In reply to Hongtao.liu from comment #5)
> > 
> > > There're several places in i386-expand.c which assume TARGET_AVX512FP16 for
> > > case V8HF/V16HF/V32HF, if we want to put V8HF/V16HF/V32HF in
> > > VALID_SSE2/AVX256/AVX512F_REG_MODE, we need to "fix" them first.
> > 
> > These are of the type:
> > 
> >       use_vector_set = TARGET_AVX512FP16 && one_var == 0;
> >       gen_vec_set_0 = gen_vec_setv8hf_0;
> > 
> > So they look immune to the above change.
> 
> This is ok.
> 
> I mean in ix86_expand_vector_init_duplicate
> 
>     case E_V8HFmode:
>     case E_V16HFmode:
>     case E_V32HFmode:
>       return ix86_vector_duplicate_value (mode, target, val);
> 
> AVX2 is needed for V8HF/V16HFmode vpbroadcastw, AVX512BW is needed for
> V32HFmode, those modes should be handled same as V8HI/V16HI/V32HImode.
> 
> Also in ix86_expand_vector_extract, below should be under TARGET_AVX512BW,
> other wise, vector_extract go through stack.
> 
>     case E_V32HFmode:
>       tmp = gen_reg_rtx (V16HFmode);
>       if (elt < 16)
> 	emit_insn (gen_vec_extract_lo_v32hf (tmp, vec));
>       else
> 	emit_insn (gen_vec_extract_hi_v32hf (tmp, vec));
>       ix86_expand_vector_extract (false, target, tmp, elt & 15);
>       return;
> 
> 
> others seems to be ok.

Please note that the change mainly affects moves between SSE and GP registers.
Expansion is done way before register allocation, and if we allow these modes
earlier, I'm not sure I understand how it affects expand.

I propose we proceed with my patch and fix eventual fallout as a follow-up.