From: Uros Bizjak <ubizjak@gmail.com>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: Hongtao Liu <crazylht@gmail.com>,
Richard Biener <richard.guenther@gmail.com>,
Richard Sandiford <richard.sandiford@arm.com>
Subject: Re: [PATCH] [PR target/97194] [AVX2] Support variable index vec_set.
Date: Thu, 12 Nov 2020 19:26:00 +0100 [thread overview]
Message-ID: <CAFULd4bad6vjVH2LeSMjG75i7KeHhCZOmjB0Oi0T7-9VizsiUg@mail.gmail.com> (raw)
In-Reply-To: <CAFULd4YPGjewc6rV5NBfmq0Lrar4DG-HXhGLx1hgJheztOZkeg@mail.gmail.com>
On Thu, Nov 12, 2020 at 6:51 PM Uros Bizjak <ubizjak@gmail.com> wrote:
> > > > Yes, removed 'code' and value_mode by checking VECTOR_MODE_P and use GET_MODE_INNER
> > > > for value_mode. ".md expanders" shall support for integer constants index mode, but
> > > > I guess they shouldn't be expanded by IFN as this function is for variable index
> > > > insert only? Anyway, the v3 patch used VOIDmode check...
> >
> > I'm not sure what best to do here, as said accepting "any" (integer) mode as
> > input is desirable (SImode, DImode but eventually also smaller modes). How
> > that can be best achieved I don't know.
>
> I was expecting something similar to how extvM/extzvM operands are
> handled here. We have:
>
> Operands 0 and 1 both have mode M. Operands 2 and 3 have a
> target-specific mode.
>
> Please note operands 2 and 3 having a "target-specific" mode, handled
> in optabs-query.c as:
>
> machine_mode struct_mode = data->operand[struct_op].mode;
> if (struct_mode == VOIDmode)
> struct_mode = word_mode;
> if (mode != struct_mode)
> return false;
>
> > Why's not specifying any mode in the patter no good? Just make sure you
> > appropriately extend/subreg it? We can make sure it will be an integer
> > mode in the expander itself.
>
> IIRC, having known mode, expanders can use create_convert_operand_to,
> and the middle-end will do the above by itself. Also note that at
> least two targets specify SImode, so register operands are currently
> ineffective there.
On a related note, the pattern is currently expanded as (see
store_bit_field_1 in expmed.c):
create_fixed_operand (&ops[0], op0);
create_input_operand (&ops[1], value, innermode);
create_integer_operand (&ops[2], pos);
I don't think calling create_integer_operand on register operand is
correct. The function comment says:
/* Make OP describe an input operand that has value INTVAL and that has
no inherent mode. This function should only be used for operands that
are always expand-time constants. The backend may request that INTVAL
be copied into a different kind of rtx, but it must specify the mode
of that rtx if so. */
Uros.
next prev parent reply other threads:[~2020-11-12 18:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 8:45 Uros Bizjak
2020-11-12 2:06 ` Hongtao Liu
2020-11-12 8:20 ` Uros Bizjak
2020-11-12 9:12 ` Hongtao Liu
2020-11-12 9:15 ` Hongtao Liu
2020-11-12 9:25 ` Hongtao Liu
2020-11-12 13:59 ` Richard Biener
2020-11-12 17:51 ` Uros Bizjak
2020-11-12 18:26 ` Uros Bizjak [this message]
2020-11-12 18:34 ` Uros Bizjak
2020-11-16 11:57 ` Uros Bizjak
2020-11-19 10:54 ` Richard Sandiford
2020-11-16 10:16 ` Uros Bizjak
-- strict thread matches above, loose matches on Subject: below --
2020-10-19 8:23 Hongtao Liu
2020-10-19 9:07 ` Richard Biener
2020-10-19 9:39 ` Hongtao Liu
2020-10-19 9:55 ` Richard Biener
2020-10-20 2:37 ` Hongtao Liu
2020-10-20 7:36 ` Richard Biener
2020-10-27 7:51 ` Hongtao Liu
2020-11-11 8:03 ` Hongtao Liu
2020-11-25 19:15 ` Jeff Law
2020-11-26 1:45 ` Hongtao Liu
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