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Peter Anvin" , Masahiro Yamada , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Michal Marek , Linux Kbuild mailing list , LKML , Kees Cook , Tony Luck , Dmitry Vyukov , Michael Ellerman , Joe Perches , Joel Fernandes , Daniel Axtens , Andy Shevchenko , Alexandru Ardelean , Yury Norov , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Ard Biesheuvel , "Paul E . McKenney" , Daniel Kiper , Bruce Ashfield , Marco Elver , Vamshi K Sthambamkadi Subject: Re: [PATCH 0/4] -ffreestanding/-fno-builtin-* patches Message-ID: <20200821191458.GA1475504@rani.riverdale.lan> References: <20200818202407.GA3143683@rani.riverdale.lan> <20200818214146.GA3196105@rani.riverdale.lan> <20200820175617.GA604994@rani.riverdale.lan> <20200821172935.GA1411923@rani.riverdale.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org On Fri, Aug 21, 2020 at 11:02:08AM -0700, Linus Torvalds wrote: > On Fri, Aug 21, 2020 at 10:54 AM Linus Torvalds > wrote: > > > > On Fri, Aug 21, 2020 at 10:29 AM Arvind Sankar wrote: > > > > > > This is why I'm saying clang's no-builtin-foo option is useful for > > > embedded: it doesn't prevent the programmer using __builtin_foo(), it > > > prevents the _compiler_ using __builtin_foo() on its own. > > > > And that's fine. But it's apparently not what gcc does. > > Oh, testing it seems to say that that is exactly what gcc does too. I > must have misunderstood some comment in this thread to mean otherwise. > > Linus How are you testing it? https://godbolt.org/z/eahdGn