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From: Jeff Law <jeffreyalaw@gmail.com>
To: Philipp Tomsich <philipp.tomsich@vrull.eu>, gcc-patches@gcc.gnu.org
Cc: Kito Cheng <kito.cheng@gmail.com>,
	Christoph Muellner <christoph.muellner@vrull.eu>,
	Vineet Gupta <vineetg@rivosinc.com>,
	Jeff Law <jlaw@ventanamicro.com>,
	Palmer Dabbelt <palmer@rivosinc.com>
Subject: Re: [PATCH] RISC-V: Use binvi to cover more immediates than with xori alone
Date: Tue, 15 Nov 2022 20:45:43 -0700	[thread overview]
Message-ID: <1c091d0d-e355-8fd8-8c6b-1bfe77f20291@gmail.com> (raw)
In-Reply-To: <20221110213501.3592470-1-philipp.tomsich@vrull.eu>


On 11/10/22 14:35, Philipp Tomsich wrote:
> Sequences of the form "a ^ C" with C being the positive half of a
> signed immediate's range with one extra bit set in addtion are mapped
> to xori and one binvi to avoid using a temporary (and a multi-insn
> sequence to load C into that temporary).
>
> gcc/ChangeLog:
>
> 	* config/riscv/bitmanip.md (*binvi<mode>_extrabit): New pattern.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/riscv/zbs-binvi.c: New test.

Could this have been potentially done by extending the ior pattern with 
a code iterator that covered IOR/XOR?


Not a big deal, but if it'd work, consider to avoid the pattern duplication.


OK.

jeff



  reply	other threads:[~2022-11-16  3:45 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-10 21:35 Philipp Tomsich
2022-11-16  3:45 ` Jeff Law [this message]
2022-11-16  9:17   ` Philipp Tomsich

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