From: Arnd Bergmann <arnd@arndb.de>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>,
linux-arm-kernel@lists.infradead.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Jon Medhurst <tixy@linaro.org>,
Marc Zyngier <marc.zyngier@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang
Date: Fri, 19 Feb 2016 15:23:16 +0100 [thread overview]
Message-ID: <3205167.CfekeqRXnt@wuerfel> (raw)
In-Reply-To: <alpine.LFD.2.20.1602181230440.13632@knanqh.ubzr>
On Thursday 18 February 2016 12:31:35 Nicolas Pitre wrote:
> On Thu, 18 Feb 2016, Arnd Bergmann wrote:
>
> > clang ignores the -mfpu=neon flag when building with -march=armv6:
> >
> > In file included from lib/raid6/neon1.c:27:
> > clang/3.8.0/include/arm_neon.h:28:2: error: "NEON support not enabled"
> >
> > There is no real need to build the file with -march=armv6 in a
> > multi-CPU enabled kernel, as nothing in here will ever get called
> > on an ARMv6 CPU. Adding -march=armv7 doesn't hurt and can only
> > improve the code quality.
>
> Is this enough to override a previous -mfpu for gcc?
I did not see any build failures on gcc with this, so I assume it
has no effect. I could move the -march=armv7-a in front of
-mfpu=neon if you think that would be safer though.
Arnd
next prev parent reply other threads:[~2016-02-19 14:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1455815113-2562966-1-git-send-email-arnd@arndb.de>
2016-02-18 17:05 ` Arnd Bergmann
2016-02-18 17:31 ` Nicolas Pitre
2016-02-19 14:23 ` Arnd Bergmann [this message]
2016-02-19 17:08 ` Nicolas Pitre
2016-02-18 17:05 ` [PATCH 2/3] [RESEND] ARM: fix copypage-*.c building " Arnd Bergmann
2016-02-18 17:34 ` Nicolas Pitre
2016-02-18 17:05 ` [PATCH 3/3] [RESEND] ARM: kprobes: use "I" constraint for inline assembly offsets Arnd Bergmann
2016-02-18 18:12 ` Jon Medhurst (Tixy)
2016-02-18 18:59 ` Robin Murphy
2016-02-19 9:34 ` Jon Medhurst (Tixy)
2016-02-18 18:24 ` Nicolas Pitre
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