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From: "juzhe.zhong@rivai.ai" <juzhe.zhong@rivai.ai>
To: "Robin Dapp" <rdapp.gcc@gmail.com>,
	 gcc-patches <gcc-patches@gcc.gnu.org>
Cc: "Robin Dapp" <rdapp.gcc@gmail.com>,
	 kito.cheng <kito.cheng@gmail.com>,
	 Kito.cheng <kito.cheng@sifive.com>,
	 jeffreyalaw <jeffreyalaw@gmail.com>
Subject: Re: Re: [PATCH] RISC-V: Fix regressions due to 86de9b66480b710202a2898cf513db105d8c432f
Date: Mon, 22 Jan 2024 19:28:19 +0800	[thread overview]
Message-ID: <CAA04928E9306D9A+2024012219281930602615@rivai.ai> (raw)
In-Reply-To: <54b40771-d5e8-42a4-a452-6874dd4b2e6d@gmail.com>

[-- Attachment #1: Type: text/plain, Size: 765 bytes --]

No, we didn't undo the optimization.

We just disallow move pattern for (set (reg) (VL_REGNUM)).




juzhe.zhong@rivai.ai
 
From: Robin Dapp
Date: 2024-01-22 19:25
To: Juzhe-Zhong; gcc-patches
CC: rdapp.gcc; kito.cheng; kito.cheng; jeffreyalaw
Subject: Re: [PATCH] RISC-V: Fix regressions due to 86de9b66480b710202a2898cf513db105d8c432f
 
Hi Juzhe,
 
in principle this seems ok to me but I wonder about:
 
> We shouldn't worry about subreg:...VL_REGNUM since it's impossible
> that we can have such situation,
 
I think we allow this in legitimize_move for situations like
(subreg:SI (reg:V4QI)).  That was not added for correctness but
optimization - are we sure we don't undo this optimization with
that change?
 
Regards
Robin
 
 

  reply	other threads:[~2024-01-22 11:28 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-22  9:05 Juzhe-Zhong
2024-01-22 11:25 ` Robin Dapp
2024-01-22 11:28   ` juzhe.zhong [this message]
2024-01-22 13:34     ` Robin Dapp

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