Messages in this thread | | | From | Masahiro Yamada <> | Date | Wed, 22 Jun 2022 10:57:34 +0900 | Subject | Re: [PATCH 0/2] Kconfig: -O3 enablement |
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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. > > 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.
If you want to say "use this option carefully", EXPERT might be another option.
depends on ARC || EXPERT
> > > > The reasoning behind this series is to open up -O3 so that bugs related > > to it (both compiler-related and kernel-related) can be discovered by > > eyeballs wanting to improve the "-O3 experience," as that might be > > beneficial to both compilers and the kernel. This has been attempted > > before [1], but unfortunately nothing ever came of it. > > > > [1] https://lore.kernel.org/lkml/20191211104619.114557-1-oleksandr@redhat.com/ > > > > Cc: linux-kbuild@vger.kernel.org > > Cc: x86@kernel.org > > Cc: Nathan Chancellor <nathan@kernel.org> > > Cc: Vlastimil Babka <vbabka@suse.cz> > > Cc: Nick Desaulniers <ndesaulniers@google.com> > > Cc: Thomas Gleixner <tglx@linutronix.de> > > Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > > Cc: Sean Christopherson <seanjc@google.com> > > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: Chris Down <chris@chrisdown.name> > > Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> > > Cc: John Ogness <john.ogness@linutronix.de> > > Cc: Elliot Berman <quic_eberman@quicinc.com> > > Cc: Oleksandr Natalenko <oleksandr@redhat.com> > > > > Miko Larsson (2): > > Kconfig: Mark -O3 as experimental > > Kconfig: Allow -O3 for all architectures > > > > init/Kconfig | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > -- > > 2.36.1 > > > > > -- > Thanks, > ~Nick Desaulniers
-- Best Regards Masahiro Yamada
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