From: Adrian Ratiu <adrian.ratiu@collabora.com> To: linux-arm-kernel@lists.infradead.org Cc: Nathan Chancellor <natechancellor@gmail.com>, Nick Desaulniers <ndesaulniers@google.com>, Arnd Bergmann <arnd@arndb.de>, clang-built-linux@googlegroups.com, Russell King <linux@armlinux.org.uk>, linux-kernel@vger.kernel.org, kernel@collabora.com Subject: [PATCH 0/2] arm: lib: xor-neon: Remove warn & disble neon vect Date: Fri, 6 Nov 2020 07:14:34 +0200 [thread overview] Message-ID: <20201106051436.2384842-1-adrian.ratiu@collabora.com> (raw) Dear all, This is my attempt to close the loop on a relatively old discussion [1] caused by a compiler bug [2]. In a nutshell, the Clang build issues a bogus warning about GCC while it silently botches the neon auto-loop vectorization. :) Many thanks to all who have investigated this issue before me. Arnd posted a workaround for xor.h [3], but I very much like his first suggestion of disabling the broken feature until the compiler is fixed. Tested on latest linux next-20201105 using bcm2835 & versatile configs and Clang 10.0.1 P.S: While testing aarch64/imx8m I also noticed vectorization is broke there as well, but that deserves its own patch because it's a separate xor-neon implementation (if this approach is deemed sensible). [1] https://patchwork.kernel.org/project/linux-arm-kernel/patch/20190528235742.105510-1-natechancellor@gmail.com/ [2] https://bugs.llvm.org/show_bug.cgi?id=40976 [3] https://bugs.llvm.org/show_bug.cgi?id=40976#c6 Kind regards, Adrian Adrian Ratiu (1): arm: lib: xor-neon: disable clang vectorization Nathan Chancellor (1): arm: lib: xor-neon: remove unnecessary GCC < 4.6 warning arch/arm/include/asm/xor.h | 3 ++- arch/arm/lib/Makefile | 3 +++ arch/arm/lib/xor-neon.c | 13 +++++-------- 3 files changed, 10 insertions(+), 9 deletions(-) -- 2.29.0
WARNING: multiple messages have this Message-ID (diff)
From: Adrian Ratiu <adrian.ratiu@collabora.com> To: linux-arm-kernel@lists.infradead.org Cc: Arnd Bergmann <arnd@arndb.de>, Nick Desaulniers <ndesaulniers@google.com>, Russell King <linux@armlinux.org.uk>, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nathan Chancellor <natechancellor@gmail.com>, kernel@collabora.com Subject: [PATCH 0/2] arm: lib: xor-neon: Remove warn & disble neon vect Date: Fri, 6 Nov 2020 07:14:34 +0200 [thread overview] Message-ID: <20201106051436.2384842-1-adrian.ratiu@collabora.com> (raw) Dear all, This is my attempt to close the loop on a relatively old discussion [1] caused by a compiler bug [2]. In a nutshell, the Clang build issues a bogus warning about GCC while it silently botches the neon auto-loop vectorization. :) Many thanks to all who have investigated this issue before me. Arnd posted a workaround for xor.h [3], but I very much like his first suggestion of disabling the broken feature until the compiler is fixed. Tested on latest linux next-20201105 using bcm2835 & versatile configs and Clang 10.0.1 P.S: While testing aarch64/imx8m I also noticed vectorization is broke there as well, but that deserves its own patch because it's a separate xor-neon implementation (if this approach is deemed sensible). [1] https://patchwork.kernel.org/project/linux-arm-kernel/patch/20190528235742.105510-1-natechancellor@gmail.com/ [2] https://bugs.llvm.org/show_bug.cgi?id=40976 [3] https://bugs.llvm.org/show_bug.cgi?id=40976#c6 Kind regards, Adrian Adrian Ratiu (1): arm: lib: xor-neon: disable clang vectorization Nathan Chancellor (1): arm: lib: xor-neon: remove unnecessary GCC < 4.6 warning arch/arm/include/asm/xor.h | 3 ++- arch/arm/lib/Makefile | 3 +++ arch/arm/lib/xor-neon.c | 13 +++++-------- 3 files changed, 10 insertions(+), 9 deletions(-) -- 2.29.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2020-11-06 5:14 UTC|newest] Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-06 5:14 Adrian Ratiu [this message] 2020-11-06 5:14 ` [PATCH 0/2] arm: lib: xor-neon: Remove warn & disble neon vect Adrian Ratiu 2020-11-06 5:14 ` [PATCH 1/2] arm: lib: xor-neon: remove unnecessary GCC < 4.6 warning Adrian Ratiu 2020-11-06 5:14 ` Adrian Ratiu 2020-11-06 14:46 ` Arnd Bergmann 2020-11-06 14:46 ` Arnd Bergmann 2020-11-06 18:03 ` Nathan Chancellor 2020-11-06 18:03 ` Nathan Chancellor 2020-11-06 21:46 ` Arnd Bergmann 2020-11-06 21:46 ` Arnd Bergmann 2020-11-06 5:14 ` [PATCH 2/2] arm: lib: xor-neon: disable clang vectorization Adrian Ratiu 2020-11-06 5:14 ` Adrian Ratiu 2020-11-06 10:14 ` Nathan Chancellor 2020-11-06 10:14 ` Nathan Chancellor 2020-11-06 11:50 ` Adrian Ratiu 2020-11-06 11:50 ` Adrian Ratiu 2020-11-06 18:01 ` Nathan Chancellor 2020-11-06 18:01 ` Nathan Chancellor 2020-11-06 19:52 ` Nick Desaulniers 2020-11-06 19:52 ` Nick Desaulniers 2020-11-07 18:07 ` Adrian Ratiu 2020-11-07 18:07 ` Adrian Ratiu 2020-11-09 19:53 ` Adrian Ratiu 2020-11-09 19:53 ` Adrian Ratiu 2020-11-10 21:41 ` Nick Desaulniers 2020-11-10 21:41 ` Nick Desaulniers 2020-11-10 22:15 ` Arvind Sankar 2020-11-10 22:15 ` Arvind Sankar 2020-11-10 22:36 ` Nick Desaulniers 2020-11-10 22:36 ` Nick Desaulniers 2020-11-10 22:39 ` Nick Desaulniers 2020-11-10 22:39 ` Nick Desaulniers 2020-11-10 22:39 ` Nick Desaulniers 2020-11-10 22:39 ` Nick Desaulniers 2020-11-10 22:54 ` Arvind Sankar 2020-11-10 22:54 ` Arvind Sankar 2020-11-10 23:56 ` Adrian Ratiu 2020-11-10 23:56 ` Adrian Ratiu 2020-11-11 0:18 ` Nick Desaulniers 2020-11-11 0:18 ` Nick Desaulniers 2020-11-11 14:15 ` Adrian Ratiu 2020-11-11 14:15 ` Adrian Ratiu 2020-11-12 21:50 ` Arvind Sankar 2020-11-12 21:50 ` Arvind Sankar 2020-11-12 21:55 ` Nick Desaulniers 2020-11-12 21:55 ` Nick Desaulniers 2020-11-07 10:22 ` Russell King - ARM Linux admin 2020-11-07 10:22 ` Russell King - ARM Linux admin 2020-11-07 18:12 ` Adrian Ratiu 2020-11-07 18:12 ` Adrian Ratiu 2020-11-08 17:40 ` Arvind Sankar 2020-11-08 17:40 ` Arvind Sankar 2020-11-08 18:09 ` Arvind Sankar 2020-11-08 18:09 ` Arvind Sankar 2020-11-08 20:14 ` Ard Biesheuvel 2020-11-08 20:14 ` Ard Biesheuvel
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20201106051436.2384842-1-adrian.ratiu@collabora.com \ --to=adrian.ratiu@collabora.com \ --cc=arnd@arndb.de \ --cc=clang-built-linux@googlegroups.com \ --cc=kernel@collabora.com \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux@armlinux.org.uk \ --cc=natechancellor@gmail.com \ --cc=ndesaulniers@google.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.