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Date: Wed, 5 Apr 2017 12:01:30 -0700
From: Matthias Kaehlcke <mka@chromium.org>
Subject: Re: [PATCH 2/7] Makefile, x86, LLVM: disable unsupported
 optimization flags
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To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michael Davidson <md@google.com>, Michal Marek <mmarek@suse.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>, Herbert Xu <herbert@gondor.apana.org.au>, "David S. Miller" <davem@davemloft.net>, Shaohua Li <shli@kernel.org>, Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, X86 ML <x86@kernel.org>, Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-crypto@vger.kernel.org, linux-raid@vger.kernel.org

Hi Masahiro,

El Thu, Apr 06, 2017 at 03:08:26AM +0900 Masahiro Yamada ha dit:

> 2017-03-17 9:15 GMT+09:00 Michael Davidson <md@google.com>:
> > Unfortunately, while clang generates a warning about these flags
> > being unsupported it still exits with a status of 0 so we have
> > to explicitly disable them instead of just using a cc-option check.
> >
> > Signed-off-by: Michael Davidson <md@google.com>
> 
> 
> Instead, does the following work for you?
> https://patchwork.kernel.org/patch/9657285/

Thanks for the pointer, I was about to give this change (or rather its
ancestor) a rework myself :)

> You need to use
> $(call cc-option, ...)
> for -falign-jumps=1 and -falign-loops=1

I can confirm that this works.

Thanks

Matthias