On Wed, 30 Sep 2020, Vineet Gupta wrote: > Hi Nicolas, > > On 9/30/20 2:23 PM, Nicolas Pitre wrote: > > Hello, > > > > I just realized you might not be aware of the following issue. > > > > The kernel kbuild test robot project identified a build failure on ARC > > that bisects down to a patch of mine. > > Your patch to Linux kernel ? Indeed the report we got for build failure didn't > provide that context and we will appreciate pointers to same just for > curiosity.
Here is the original report: https://www.spinics.net/lists/kernel/msg3596096.html > > It turns out that my patch is > > highlighting a bug in gcc for ARC. > > In any case, we did reach the same conclusion it is indeed an ARC gcc bug > (for Big > endian builds only) and have created a github ticket for our gcc maintainer to > resolve. Please note that we've not seen it internally as Big Endian is an > optional configuration option and not in wide spread use for us. > > https://github.com/foss-for-synopsys-dwc-arc-processors/toolchain/issues/300 > > > And we can also confirm this is seen in gcc 9 and gcc 10 both. > > Thx, > -Vineet > > > > > ---------- Forwarded message ---------- > > Date: Mon, 28 Sep 2020 17:43:20 -0400 (EDT) > > From: Nicolas Pitre <n...@fluxnic.net> > > To: Rong Chen <rong.a.c...@intel.com> > > Cc: kernel test robot <l...@intel.com>, kbuild-...@lists.01.org, > > linux-ker...@vger.kernel.org, Arnd Bergmann <a...@arndb.de>, > > g...@gcc.gnu.org > > Message-ID: <nycvar.ysq.7.78.906.2009281705410.1...@knanqh.ubzr> > > Subject: Re: {standard input}:1174: Error: inappropriate arguments for > > opcode > > 'mpydu' > > > > On Sun, 27 Sep 2020, Rong Chen wrote: > > > >> Hi Nicolas, > >> > >> Thanks for the feedback, the error still remains with gcc 10.2.0: > > I've created the simplest test case that can be. You won't believe it. > > > > Test case: > > > > $ cat test.c > > unsigned int test(unsigned int x, unsigned long long y) > > { > > y /= 0x20000000; > > if (x > 1) > > y *= x; > > return y; > > } > > $ export > > LD_LIBRARY_PATH=$LD_LIBRARY_PATH:~/0day/gcc-9.3.0-nolibc/arc-elf/libexec/gcc/arc-elf/9.3.0 > > $ ~/0day/gcc-9.3.0-nolibc/arc-elf/bin/arc-elf-gcc -mcpu=hs38 -mbig-endian > > -O2 -c test.c > > /tmp/cc0GAomh.s: Assembler messages: > > /tmp/cc0GAomh.s:21: Error: inappropriate arguments for opcode 'mpydu' > > > > I know nothing about ARC. Please anyone take it over from here. > > > > > > Nicolas > > _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
