From: Jeff Law <jeffreyalaw@gmail.com>
To: "Christoph Müllner" <christoph.muellner@vrull.eu>
Cc: gcc-patches@gcc.gnu.org, Kito Cheng <kito.cheng@sifive.com>,
Jim Wilson <jim.wilson.gcc@gmail.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Andrew Waterman <andrew@sifive.com>,
Philipp Tomsich <philipp.tomsich@vrull.eu>,
Vineet Gupta <vineetg@rivosinc.com>
Subject: Re: [PATCH 7/7] riscv: Add support for str(n)cmp inline expansion
Date: Mon, 14 Nov 2022 17:22:47 -0700 [thread overview]
Message-ID: <6395fbc9-6874-55f9-9ea0-5d4f87b1b83e@gmail.com> (raw)
In-Reply-To: <CAEg0e7gkYBc8-tONaD0TwEhLL-NyvPEcgBaD-8qsmyUPNNA0YA@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 805 bytes --]
On 11/14/22 14:49, Christoph Müllner wrote:
>
>
> We can take this further, but then the following questions pop up:
> * how much data processing per loop iteration?
I have no idea because I don't have any real data. Last time I gathered
any data on this issue was circa 1988 :-)
> * what about unaligned strings?
I'd punt. I don't think we can depend on having a high performance
unaligned access. You could do a dynamic check of alignment, but you'd
really need to know that they're aligned often enough that the dynamic
check can often be recovered.
>
> Happy to get suggestions/opinions for improvement.
I think this is pretty good without additional data that would indicate
that handling unaligned cases or a different number of loop peels would
be a notable improvement.
Jeff
next prev parent reply other threads:[~2022-11-15 0:22 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-13 23:05 [PATCH 0/7] riscv: Improve builtins expansion Christoph Muellner
2022-11-13 23:05 ` [PATCH 1/7] riscv: bitmanip: add orc.b as an unspec Christoph Muellner
2022-11-14 16:51 ` Jeff Law
2022-11-14 17:53 ` Jeff Law
2022-11-14 19:05 ` Philipp Tomsich
2022-11-13 23:05 ` [PATCH 2/7] riscv: bitmanip/zbb: Add prefix/postfix and enable visiblity Christoph Muellner
2022-11-14 16:55 ` Jeff Law
2022-11-13 23:05 ` [PATCH 3/7] riscv: Enable overlap-by-pieces via tune param Christoph Muellner
2022-11-14 2:48 ` Vineet Gupta
2022-11-14 7:59 ` Philipp Tomsich
2022-11-14 8:29 ` Christoph Müllner
2022-11-14 19:04 ` Jeff Law
2022-11-14 19:07 ` Christoph Müllner
2022-11-13 23:05 ` [PATCH 4/7] riscv: Move riscv_block_move_loop to separate file Christoph Muellner
2022-11-14 16:56 ` Jeff Law
2022-11-13 23:05 ` [PATCH 5/7] riscv: Use by-pieces to do overlapping accesses in block_move_straight Christoph Muellner
2022-11-14 17:16 ` Jeff Law
2022-11-14 19:01 ` Christoph Müllner
2022-11-14 19:05 ` Jeff Law
2022-11-13 23:05 ` [PATCH 6/7] riscv: Add support for strlen inline expansion Christoph Muellner
2022-11-14 18:17 ` Jeff Law
2022-11-14 21:07 ` Christoph Müllner
2022-11-13 23:05 ` [PATCH 7/7] riscv: Add support for str(n)cmp " Christoph Muellner
2022-11-14 19:28 ` Jeff Law
2022-11-14 21:49 ` Christoph Müllner
2022-11-15 0:22 ` Jeff Law [this message]
2022-11-15 0:46 ` Kito Cheng
2022-11-15 0:53 ` Palmer Dabbelt
2022-11-15 1:55 ` Kito Cheng
2022-11-15 3:41 ` Jeff Law
2022-11-15 22:22 ` Christoph Müllner
2022-11-16 0:15 ` Philipp Tomsich
2022-11-21 3:24 ` Kito Cheng
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