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From: Arnd Bergmann <arnd@arndb.de>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Miko Larsson <mikoxyzzz@gmail.com>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>, Nathan Chancellor <nathan@kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Sean Christopherson <seanjc@google.com>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>, Chris Down <chris@chrisdown.name>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	John Ogness <john.ogness@linutronix.de>,
	Elliot Berman <quic_eberman@quicinc.com>,
	Oleksandr Natalenko <oleksandr@redhat.com>
Subject: Re: [PATCH 0/2] Kconfig: -O3 enablement
Date: Thu, 23 Jun 2022 19:27:29 +0200	[thread overview]
Message-ID: <CAK8P3a2SkawPCtBgm4J9rUawRYa1CT_-BqTbdE-SUUa=9VC2pg@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNAT3FrpLnhSgfTo5bxk-9cHm6g1ti58wSY6W-fxMx+mUrA@mail.gmail.com>

On Wed, Jun 22, 2022 at 3:57 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
> On Wed, Jun 22, 2022 at 1:17 AM Nick Desaulniers <ndesaulniers@google.com> wrote:
> >
> > On Tue, Jun 21, 2022 at 6:35 AM Miko Larsson <mikoxyzzz@gmail.com> wrote:
> > >
> > > Hi,
> > >
> > > This very small series allows -O3 to be used for all architectures. The
> > > first patch marks -O3 as experimental, with the reasoning being that it
> > > might expose unwanted regressions to users, and the second patch
> > > actually allows -O3 by removing the "depend on ARC" string.
> >
> > I think we should just remove -O3 support from KCONFIG.

I agree that would be best

> > If someone wants to mess around with "experimental features," there's
> > nothing stopping you from doing:
> >
> > $ make KCFLAGS=-O3
> >
>
> ARC uses -O3 since day1.
>
> "Generic build system uses -O2, we want -O3"
> in commit cfdbc2e16e65c1ec1c23057640607cee98d1a1bd
>
> If they want -O3, it is up to the ARC maintainer.

I suppose whatever the reason for using -O3 at the time has
likely changed by now.

> If you want to say "use this option carefully",
> EXPERT might be another option.
>
>     depends on ARC || EXPERT

This probably also needs a dependency on !COMPILE_TEST so we don't
report compile-time problems that are specific to -O3. Maybe a good first
step would be to turn this into

      depends on ARCH && EXPERT && !COMPILE_TEST

which should help both with compile-testing on ARC, and it would
prevent it from being visible on other architectures.

        Arnd

  parent reply	other threads:[~2022-06-23 18:28 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-21 13:35 [PATCH 0/2] Kconfig: -O3 enablement Miko Larsson
2022-06-21 13:35 ` [PATCH 1/2] Kconfig: Mark -O3 as experimental Miko Larsson
2022-06-21 13:35 ` [PATCH 2/2] Kconfig: Allow -O3 for all architectures Miko Larsson
2022-06-21 16:16 ` [PATCH 0/2] Kconfig: -O3 enablement Nick Desaulniers
2022-06-22  1:57   ` Masahiro Yamada
2022-06-23 15:42     ` Miko Larsson
2022-06-23 15:44       ` Masahiro Yamada
2022-06-23 17:00         ` Miko Larsson
2022-06-23 17:15           ` Masahiro Yamada
2022-06-23 17:44             ` Miko Larsson
2022-06-23 17:27     ` Arnd Bergmann [this message]
2022-06-24 18:29 Linus Torvalds
     [not found] ` <CA+55aFyugRmHNV1BbhB_YHf3mgaiU6ND_KL8bu0PPEaRVNwWHg@mail.gmail.com>
2022-06-24 18:38   ` Linus Torvalds

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