Re: [RFC PATCH] Remove Intel compiler support

From: Nick Desaulniers <ndesaulniers@google.com>
To: Arnd Bergmann <arnd@arndb.de>, Masahiro Yamada <masahiroy@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-ia64@vger.kernel.org, Miguel Ojeda <ojeda@kernel.org>,
	Len Brown <lenb@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Terrell <terrelln@fb.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Robert Moore <robert.moore@intel.com>, Tom Rix <trix@redhat.com>,
	devel@acpica.org, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [RFC PATCH] Remove Intel compiler support
Date: Tue, 11 Oct 2022 09:43:38 -0700	[thread overview]
Message-ID: <CAKwvOdm3z2MWzxTuK9e=eZXWLEBgnkT3NC-ALKNB8z7L9PnfQw@mail.gmail.com> (raw)
In-Reply-To: <08db7754-ecd8-4425-875b-4f2b44497f6b@app.fastmail.com>

On Tue, Oct 11, 2022 at 8:18 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Tue, Oct 11, 2022, at 5:18 AM, Masahiro Yamada wrote:
> > include/linux/compiler-intel.h had no update in the past 3 years.
> >
> > We often forget about the third C compiler to build the kernel.
> >
> > For example, commit a0a12c3ed057 ("asm goto: eradicate CC_HAS_ASM_GOTO")
> > only mentioned GCC and Clang.
> >
> > init/Kconfig defines CC_IS_GCC and CC_IS_CLANG but not CC_IS_ICC,
> > and nobody has reported any issue.
> >
> > I guess the Intel Compiler support is broken, and nobody is caring
> > about it.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> > ---
> >
> > I am sending this to Linus and the x86 maintainers with RFC.
> > If somebody is still using ICC, please speak up!
>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
>
>
> I had the same thought a while back and tried to show that it as
> already broken, but I never managed to actually download the compiler
> at the time.
>
> It appears that in the meantime, Intel have completely dropped their
> old codebase and moved to using LLVM[1], so my guess is that with the
> current releases it will behave the same as clang. It might help
> to verify that this is indeed the case if you want to add that
> to the changelog text.

This is my thought, too.  I'm happy to help folks working on icx to
get icx up and running for kernel builds, if there's interest.

Change LGTM; there's probably some refactoring we might be able to do
as a result of this; we might be able to move more common definitions
out of include/linux/compiler-gcc.h and include/linux/compiler-clang.h
into include/linux/compiler_types.h, but that can wait until after
this change.

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

>
>      Arnd
>
> [1] https://www.intel.com/content/www/us/en/developer/articles/technical/adoption-of-llvm-complete-icx.html

-- 
Thanks,
~Nick Desaulniers