From: Segher Boessenkool <segher@kernel.crashing.org>
To: Jiufu Guo <guojiufu@linux.ibm.com>
Cc: Jiufu Guo via Gcc-patches <gcc-patches@gcc.gnu.org>,
"Kewen.Lin" <linkw@linux.ibm.com>,
dje.gcc@gmail.com, linkw@gcc.gnu.org
Subject: Re: [PATCH V2] rs6000: Support to build constants by li/lis+oris/xoris
Date: Mon, 28 Nov 2022 11:19:50 -0600 [thread overview]
Message-ID: <20221128171950.GN25951@gate.crashing.org> (raw)
In-Reply-To: <7e5yez1ppc.fsf@pike.rch.stglabs.ibm.com>
On Mon, Nov 28, 2022 at 03:51:59PM +0800, Jiufu Guo wrote:
> Jiufu Guo via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> > Segher Boessenkool <segher@kernel.crashing.org> writes:
> >>> > + else
> >>> > + {
> >>> > + emit_move_insn (temp,
> >>> > + GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
> >>> > + if (ud1 != 0)
> >>> > + emit_move_insn (temp, gen_rtx_IOR (DImode, temp, GEN_INT (ud1)));
> >>> > + emit_move_insn (dest,
> >>> > + gen_rtx_ZERO_EXTEND (DImode,
> >>> > + gen_lowpart (SImode, temp)));
> >>> > + }
> >>
> >> Why this? Please just write it in DImode, do not go via SImode?
> > Thanks for catch this. Yes, gen_lowpart with DImode would be ok.
> Oh, Sorry. DImode can not be used here. The genreated pattern with
> DImode can not be recognized. Using SImode is to match 'rlwxx'.
There are patterns that accept DImode for rlwinm just fine. Please use
(and:DI (const_int 0xffffffff) (x:DI))
not the obfuscated
(zero_extend:DI (subreg:SI (x:DI) LOWBYTE))
Segher
next prev parent reply other threads:[~2022-11-28 17:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-26 11:40 Jiufu Guo
2022-10-27 5:19 ` Jiufu Guo
2022-11-09 3:29 ` Ping: " Jiufu Guo
2022-11-25 8:11 ` Kewen.Lin
2022-11-25 12:41 ` Jiufu Guo
2022-11-25 14:43 ` Segher Boessenkool
2022-11-28 3:37 ` Jiufu Guo
2022-11-28 7:51 ` Jiufu Guo
2022-11-28 17:19 ` Segher Boessenkool [this message]
2022-11-29 13:14 ` Jiufu Guo
2022-12-01 1:48 ` Jiufu Guo
2022-11-28 14:18 ` Segher Boessenkool
2022-11-29 9:08 ` Jiufu Guo
2022-12-01 8:56 ` Jiufu Guo
2022-11-30 4:30 ` Jiufu Guo
2022-12-01 1:51 ` Jiufu Guo
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