From: 钟居哲 <juzhe.zhong@rivai.ai>
To: richard.sandiford <richard.sandiford@arm.com>
Cc: gcc-patches <gcc-patches@gcc.gnu.org>, rguenther <rguenther@suse.de>
Subject: Re: Re: [PATCH V14] VECT: Add decrement IV iteration loop control by variable amount support
Date: Wed, 24 May 2023 23:52:22 +0800 [thread overview]
Message-ID: <70D20B75C645F088+2023052423522166255038@rivai.ai> (raw)
In-Reply-To: <mpth6s1enph.fsf@arm.com>
[-- Attachment #1: Type: text/plain, Size: 1631 bytes --]
Oh. I see. Thank you so much for pointing this.
Could you tell me what I should do in the codes?
It seems that I should adjust it in
vect_adjust_loop_lens_control
muliply by some factor ? Is this correct multiply by max_nscalars_per_iter
?
Thanks.
juzhe.zhong@rivai.ai
From: Richard Sandiford
Date: 2023-05-24 23:47
To: 钟居哲
CC: gcc-patches; rguenther
Subject: Re: [PATCH V14] VECT: Add decrement IV iteration loop control by variable amount support
钟居哲 <juzhe.zhong@rivai.ai> writes:
> Hi, Richard. I still don't understand it. Sorry about that.
>
>>> loop_len_48 = MIN_EXPR <loop_len_34 * 2, 4>;
> >> _74 = loop_len_34 * 2 - loop_len_48;
>
> I have the tests already tested.
> We have a MIN_EXPR to calculate the total elements:
> loop_len_34 = MIN_EXPR <ivtmp_72, 8>;
> I think "8" is already multiplied by 2?
>
> Why do we need loop_len_34 * 2 ?
> Could you give me more informations, The similiar tests you present we already have
> execution check and passed. I am not sure whether this patch has the issue that I didn't notice.
Think about the maximum values of each SSA name:
loop_len_34 = MIN_EXPR <ivtmp_72, 8>; // MAX 8
loop_len_48 = MIN_EXPR <loop_len_34, 4>; // MAX 4
_74 = loop_len_34 - loop_len_48; // MAX 4
loop_len_49 = MIN_EXPR <_74, 4>; // MAX 4 (always == _74)
_75 = _74 - loop_len_49; // 0
loop_len_50 = MIN_EXPR <_75, 4>; // 0
loop_len_51 = _75 - loop_len_50; // 0
So the final two y vectors will always have 0 controls.
Thanks,
Richard
next prev parent reply other threads:[~2023-05-24 15:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-24 14:48 juzhe.zhong
2023-05-24 15:07 ` Richard Sandiford
2023-05-24 15:13 ` 钟居哲
2023-05-24 15:31 ` Richard Sandiford
2023-05-24 15:42 ` 钟居哲
2023-05-24 15:47 ` Richard Sandiford
2023-05-24 15:52 ` 钟居哲 [this message]
2023-05-24 16:00 ` Richard Sandiford
2023-05-24 16:15 ` 钟居哲
2023-05-24 16:37 ` 钟居哲
2023-05-24 20:05 ` Richard Sandiford
2023-05-25 3:05 ` juzhe.zhong
[not found] ` <2023052423130398041121@rivai.ai>
2023-05-24 15:31 ` 回复: " 钟居哲
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