On Mon, Dec 3, 2018 at 2:24 AM Joel Stanley <j...@jms.id.au> wrote: > > On Sat, 3 Nov 2018 at 04:04, Nick Desaulniers <ndesaulni...@google.com> wrote: > > > > On Thu, Nov 1, 2018 at 5:45 PM Joel Stanley <j...@jms.id.au> wrote: > > > > > > We cannot build these files with clang as it does not allow altivec > > > instructions in assembly when -msoft-float is passed. > > > > > > Jinsong Ji <j...@us.ibm.com> wrote: > > > > We currently disable Altivec/VSX support when enabling soft-float. So > > > > any usage of vector builtins will break. > > > > > > > > Enable Altivec/VSX with soft-float may need quite some clean up work, so > > > > I guess this is currently a limitation. > > > > > > > > Removing -msoft-float will make it work (and we are lucky that no > > > > floating point instructions will be generated as well). > > > > > > This is a workaround until the issue is resolved in clang. > > > > > > Link: https://bugs.llvm.org/show_bug.cgi?id=31177 > > > Link: https://github.com/ClangBuiltLinux/linux/issues/239 > > > Signed-off-by: Joel Stanley <j...@jms.id.au> > > > --- > > > v2: fix typo in comment, thanks Jinsong > > > > > > lib/raid6/Makefile | 15 +++++++++++++++ > > > 1 file changed, 15 insertions(+) > > > > > > diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile > > > index 2f8b61dfd9b0..7ed43eaa02ef 100644 > > > --- a/lib/raid6/Makefile > > > +++ b/lib/raid6/Makefile > > > @@ -18,6 +18,21 @@ quiet_cmd_unroll = UNROLL $@ > > > > > > ifeq ($(CONFIG_ALTIVEC),y) > > > altivec_flags := -maltivec $(call cc-option,-mabi=altivec) > > > + > > > +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 > > > +CFLAGS_REMOVE_altivec1.o += -msoft-float > > > +CFLAGS_REMOVE_altivec2.o += -msoft-float > > > +CFLAGS_REMOVE_altivec4.o += -msoft-float > > > +CFLAGS_REMOVE_altivec8.o += -msoft-float > > > +CFLAGS_REMOVE_altivec8.o += -msoft-float > > > +CFLAGS_REMOVE_vpermxor1.o += -msoft-float > > > +CFLAGS_REMOVE_vpermxor2.o += -msoft-float > > > +CFLAGS_REMOVE_vpermxor4.o += -msoft-float > > > +CFLAGS_REMOVE_vpermxor8.o += -msoft-float > > > +endif > > > > Hi Joel, thanks for this patch! My same thoughts about > > CONFIG_CC_IS_CLANG vs cc-option from > > https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-November/180939.html > > apply here as well. I don't feel strongly about either though. What > > are your thoughts? > > I'm not sure that we can test for this one with cc-option. The result > of having -maltivec with -msoft-float is a error about the internals > of clang, which isn't something that kbuild is set up to test for.
As in clang itself crashes, and cc-option/kbuild can't handle that gracefully? > > When clang is fixed to allow this combination we will still build this > code in the same way, so in that sense it fails "open". > > Cheers, > > Joel -- Thanks, ~Nick Desaulniers