Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 3 Dec 2018 17:24:41 -0600
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Joel Stanley <joel@jms.id.au>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        Kees Cook <keescook@chromium.org>,
        Arnd Bergmann <arnd@arndb.de>, Jinsong Ji <jji@us.ibm.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] raid6/ppc: Fix build for clang
Message-ID: <20181203232440.GB3803@gate.crashing.org>
References: <20181102004455.10157-1-joel@jms.id.au> <CAKwvOdni_iJ4beAWYkUUpZss_PYZezMGR7hN9k1rm9J0iB0gHQ@mail.gmail.com> <CACPK8XdbWzb=52iFV_fj0Y5KMWPgsRv_A8PZgfKn9vm96y3LOw@mail.gmail.com> <CAKwvOdndyeRZApOqbp-6evEpYgzHyGo4qqaMKd_DQ4U9x8_5wA@mail.gmail.com> <CACPK8Xcz4YzfnFAHGOcJZkt0UFfQ02YabtEQDHXdSFsH57xRiQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CACPK8Xcz4YzfnFAHGOcJZkt0UFfQ02YabtEQDHXdSFsH57xRiQ@mail.gmail.com>
User-Agent: Mutt/1.4.2.3i
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Dec 04, 2018 at 08:43:47AM +1030, Joel Stanley wrote:
> On Tue, 4 Dec 2018 at 05:15, Nick Desaulniers <ndesaulniers@google.com> wrote:
> > > > > +ifdef CONFIG_CC_IS_CLANG
> > > > > +# clang ppc port does not yet support -maltivec when -msoft-float is
> > > > > +# enabled. A future release of clang will resolve this
> > > > > +# https://bugs.llvm.org/show_bug.cgi?id=31177

> > As in clang itself crashes, and cc-option/kbuild can't handle that gracefully?
> 
> The developer gets something like this:
> 
> SplitVectorResult #0: t196: v16i8 = llvm.ppc.altivec.vcmpgtsb
> TargetConstant:i64<4823>, t146, t195
> fatal error: error in backend: Do not know how to split the result of
> this operator!
> clang-8: error: clang frontend command failed with exit code 70 (use
> -v to see invocation)

-msoft-float simply means not to use FPRs, and nothing more or less, so
that is a pretty interesting failure (will probably turn out to be a typo
or something else boring, but it is fun while it lasts).


Segher