From: Uros Bizjak <ubizjak@gmail.com>
To: Hongtao Liu <crazylht@gmail.com>
Cc: Jakub Jelinek <jakub@redhat.com>,
GCC Patches <gcc-patches@gcc.gnu.org>,
Kirill Yukhin <kirill.yukhin@gmail.com>
Subject: Re: [PATCH]i386: Optimize pmovskb on zero_extend of subreg HI of the result [PR98461]
Date: Tue, 5 Jan 2021 08:19:58 +0100 [thread overview]
Message-ID: <CAFULd4ZtYegmmO-CWR1A__p8UHss4BgvqK48msydc-9_qXpn3g@mail.gmail.com> (raw)
In-Reply-To: <CAFULd4ZYc4QnfG99XhUcTgNE-qOj9H6SzAwpmcOrYhf5_0RbyA@mail.gmail.com>
On Tue, Jan 5, 2021 at 8:04 AM Uros Bizjak <ubizjak@gmail.com> wrote:
> >
> > +(define_split
> > + [(set (match_operand:SI 0 "register_operand")
> > + (zero_extend:SI
> > + (not:HI
> > + (subreg:HI
> > + (unspec:SI
> > + [(match_operand:V16QI 1 "register_operand")]
> > + UNSPEC_MOVMSK) 0))))]
> > + "TARGET_SSE2"
> > + [(set (match_dup 2)
> > + (unspec:SI [(match_dup 1)] UNSPEC_MOVMSK))
> > + (set (match_dup 0)
> > + (match_dup 3))]
>
> Just write:
>
> (set (match_dup 0)
> (xor:SI (match_dup 2)(const_int 65535))
BTW: This could be a universal combine splitter to simplify
unsigned int foo (unsigned short z)
{
return (unsigned short)~z;
}
Trying 7 -> 8:
7: r87:HI=~r88:SI#0
REG_DEAD r88:SI
8: r86:SI=zero_extend(r87:HI)
REG_DEAD r87:HI
Failed to match this instruction:
(set (reg:SI 86)
(zero_extend:SI (not:HI (subreg:HI (reg:SI 88) 0))))
But combine does not "split" to one insns.
Uros.
next prev parent reply other threads:[~2021-01-05 7:20 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-04 5:56 Hongtao Liu
2021-01-04 7:40 ` Uros Bizjak
2021-01-04 7:54 ` Hongtao Liu
2021-01-04 8:42 ` Uros Bizjak
2021-01-04 8:49 ` Jakub Jelinek
2021-01-04 8:59 ` Hongtao Liu
2021-01-05 6:32 ` Hongtao Liu
2021-01-05 7:04 ` Uros Bizjak
2021-01-05 7:19 ` Uros Bizjak [this message]
2021-01-05 10:28 ` Hongtao Liu
2021-01-05 10:30 ` Uros Bizjak
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