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Date: Mon, 30 Oct 2017 17:13:53 +0000
From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Robert Jarzmik <robert.jarzmik@free.fr>,
        Aaro Koskinen <aaro.koskinen@iki.fi>,
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        Sven Schmidt <4sschmid@informatik.uni-hamburg.de>,
        Petr Cvek <petrcvekcz@gmail.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] ARM: add a private asm/unaligned.h
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On Mon, Oct 30, 2017 at 06:01:44PM +0100, Arnd Bergmann wrote:
> Right, either fail the build or use the workaround from the gcc bugzilla,
> passing -fno-store-merging to the broken compilers avoids the problem
> reliably at the cost of slightly worse code. For the decompressor, we might
> also get away with passing -march=armv5t (not armv5te), which has
> experimentally been found to avoid the problem and produce better code
> than "-march=armv6 -fno-store-merging" as it avoids the strd instruction
> but not other store merging.

Depends how important the compilers are...

We currently refuse to build using these compilers:

gcc = 3.x where x < 3
gcc = 4.x where x < 3 if unwinding is enabled
gcc = 4.8.x where x < 3

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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