Re: [PATCH] x86: avoid maybe_gen_...()

[Hongtao Liu <crazylht@gmail.com>]

On Fri, Jul 14, 2023 at 5:42 PM Jan Beulich via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> In the (however unlikely) event that no insn can be found for the
> requested mode, using maybe_gen_...() without (really) checking its
> result for being a null rtx would lead to silent bad code generation.
Ok.
>
> gcc/
>
>         * config/i386/i386-expand.cc (ix86_expand_vector_init_duplicate):
>         Use gen_vec_set_0.
>         (ix86_expand_vector_extract): Use gen_vec_extract_lo /
>         gen_vec_extract_hi.
>         (expand_vec_perm_broadcast_1): Use gen_vec_interleave_high /
>         gen_vec_interleave_low. Rename local variable.
>
> --- a/gcc/config/i386/i386-expand.cc
> +++ b/gcc/config/i386/i386-expand.cc
> @@ -15456,8 +15456,7 @@ ix86_expand_vector_init_duplicate (bool
>             {
>               tmp1 = force_reg (GET_MODE_INNER (mode), val);
>               tmp2 = gen_reg_rtx (mode);
> -             emit_insn (maybe_gen_vec_set_0 (mode, tmp2,
> -                                             CONST0_RTX (mode), tmp1));
> +             emit_insn (gen_vec_set_0 (mode, tmp2, CONST0_RTX (mode), tmp1));
>               tmp1 = gen_lowpart (mode, tmp2);
>             }
>           else
> @@ -17419,9 +17418,9 @@ ix86_expand_vector_extract (bool mmx_ok,
>                  ? gen_reg_rtx (V16HFmode)
>                  : gen_reg_rtx (V16BFmode));
>           if (elt < 16)
> -           emit_insn (maybe_gen_vec_extract_lo (mode, tmp, vec));
> +           emit_insn (gen_vec_extract_lo (mode, tmp, vec));
>           else
> -           emit_insn (maybe_gen_vec_extract_hi (mode, tmp, vec));
> +           emit_insn (gen_vec_extract_hi (mode, tmp, vec));
>           ix86_expand_vector_extract (false, target, tmp, elt & 15);
>           return;
>         }
> @@ -17435,9 +17434,9 @@ ix86_expand_vector_extract (bool mmx_ok,
>                  ? gen_reg_rtx (V8HFmode)
>                  : gen_reg_rtx (V8BFmode));
>           if (elt < 8)
> -           emit_insn (maybe_gen_vec_extract_lo (mode, tmp, vec));
> +           emit_insn (gen_vec_extract_lo (mode, tmp, vec));
>           else
> -           emit_insn (maybe_gen_vec_extract_hi (mode, tmp, vec));
> +           emit_insn (gen_vec_extract_hi (mode, tmp, vec));
>           ix86_expand_vector_extract (false, target, tmp, elt & 7);
>           return;
>         }
> @@ -22501,18 +22500,18 @@ expand_vec_perm_broadcast_1 (struct expa
>        if (d->testing_p)
>         return true;
>
> -      rtx (*maybe_gen) (machine_mode, int, rtx, rtx, rtx);
> +      rtx (*gen_interleave) (machine_mode, int, rtx, rtx, rtx);
>        if (elt >= nelt2)
>         {
> -         maybe_gen = maybe_gen_vec_interleave_high;
> +         gen_interleave = gen_vec_interleave_high;
>           elt -= nelt2;
>         }
>        else
> -       maybe_gen = maybe_gen_vec_interleave_low;
> +       gen_interleave = gen_vec_interleave_low;
>        nelt2 /= 2;
>
>        dest = gen_reg_rtx (vmode);
> -      emit_insn (maybe_gen (vmode, 1, dest, op0, op0));
> +      emit_insn (gen_interleave (vmode, 1, dest, op0, op0));
>
>        vmode = V4SImode;
>        op0 = gen_lowpart (vmode, dest);



-- 
BR,
Hongtao