Messages in this thread | | | From | Nick Desaulniers <> | Date | Fri, 2 Nov 2018 10:34:44 -0700 | Subject | Re: [PATCH v2] raid6/ppc: Fix build for clang |
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On Thu, Nov 1, 2018 at 5:45 PM Joel Stanley <joel@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 <jji@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 <joel@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?
> endif > > # The GCC option -ffreestanding is required in order to compile code containing > -- > 2.19.1 >
-- Thanks, ~Nick Desaulniers
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