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From: Arnd Bergmann <arnd@arndb.de>
To: linux-arch <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Vineet Gupta <vgupta@synopsys.com>,
	 Russell King <linux@armlinux.org.uk>,
	Nathan Chancellor <nathan@kernel.org>,
	 Nick Desaulniers <ndesaulniers@google.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	 clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [RFC 06/12] asm-generic: unaligned: remove byteshift helpers
Date: Sat, 8 May 2021 13:38:01 +0200	[thread overview]
Message-ID: <CAK8P3a3GP7Wwyes_08nRQ-ESfx2dQr2Ygdz6jpSC1754M2s82A@mail.gmail.com> (raw)
In-Reply-To: <20210507220813.365382-7-arnd@kernel.org>

On Sat, May 8, 2021 at 12:11 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> I've included this patch in the series because Linus asked about
> removing the byteshift version, but after trying it out, I'd
> prefer to drop this and use the byteshift version for the
> generic code as well.

Update: I've tried to create a small test case that illustrates the problem
with using the swab() based version, however all cases combinations
I tried showed either both producing identical output, or the shift
version being worse, see https://godbolt.org/z/bTdsjnjfT

I'll rewrite the patch description accordingly and leave this in place.

       Arnd

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  reply	other threads:[~2021-05-08 11:40 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-07 22:07 [RFC 0/12] Unify asm/unaligned.h around struct helper Arnd Bergmann
2021-05-07 22:07 ` [RFC 06/12] asm-generic: unaligned: remove byteshift helpers Arnd Bergmann
2021-05-08 11:38   ` Arnd Bergmann [this message]
2021-05-07 22:07 ` [RFC 07/12] asm-generic: unaligned always use struct helpers Arnd Bergmann
2021-05-07 22:07 ` [RFC 0/12] Unify asm/unaligned.h around struct helper Arnd Bergmann

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