| Message ID | 20181031032829.18131-1-joel@jms.id.au |
|---|---|
| State | Superseded |
| Headers | show |
| Series | raid6/ppc: Fix build for clang | expand |
On Tue, Oct 30, 2018 at 8:28 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> Hopefully we can have this fixed up soon. I'll try to see who works on Clang+PPC here and see if they can help move that bug along. Thanks for the patch! > --- > lib/raid6/Makefile | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile > index 2f8b61dfd9b0..3a844e6fd01c 100644 > --- a/lib/raid6/Makefile > +++ b/lib/raid6/Makefile > @@ -18,6 +18,21 @@ quiet_cmd_unroll = UNROLL $@ > > ifeq ($(CONFIG_ALTIVEC),y) > altivec_flags := -maltivec $(call cc-option,-mabi=altivec) > + > +ifdef CONFIG_CC_IS_CLANG Note that the top level makefile detects clang via: ifeq ($(cc-name),clang) Does that not work here? I'd prefer to keep compiler detection in Makefiles consistent, if it works? > +# clang ppc port does not yet support -maltifec 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 > endif > > # The GCC option -ffreestanding is required in order to compile code containing > -- > 2.19.1 > -- Thanks, ~Nick Desaulniers
Nick Desaulniers <ndesaulniers@google.com> writes: > On Tue, Oct 30, 2018 at 8:28 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> > > Hopefully we can have this fixed up soon. I'll try to see who works > on Clang+PPC here and see if they can help move that bug along. Thanks > for the patch! > >> --- >> lib/raid6/Makefile | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile >> index 2f8b61dfd9b0..3a844e6fd01c 100644 >> --- a/lib/raid6/Makefile >> +++ b/lib/raid6/Makefile >> @@ -18,6 +18,21 @@ quiet_cmd_unroll = UNROLL $@ >> >> ifeq ($(CONFIG_ALTIVEC),y) >> altivec_flags := -maltivec $(call cc-option,-mabi=altivec) >> + >> +ifdef CONFIG_CC_IS_CLANG > > Note that the top level makefile detects clang via: > > ifeq ($(cc-name),clang) > > Does that not work here? I'd prefer to keep compiler detection in > Makefiles consistent, if it works? cc-name is being removed in favor of CONFIG_CC_IS_CLANG: https://lore.kernel.org/lkml/1540905994-6073-1-git-send-email-yamada.masahiro@socionext.com/ cheers
On Wed, Oct 31, 2018 at 9:38 PM Michael Ellerman <mpe@ellerman.id.au> wrote: > > Nick Desaulniers <ndesaulniers@google.com> writes: > > On Tue, Oct 30, 2018 at 8:28 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> > > > > Hopefully we can have this fixed up soon. I'll try to see who works > > on Clang+PPC here and see if they can help move that bug along. Thanks > > for the patch! > > > >> --- > >> lib/raid6/Makefile | 15 +++++++++++++++ > >> 1 file changed, 15 insertions(+) > >> > >> diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile > >> index 2f8b61dfd9b0..3a844e6fd01c 100644 > >> --- a/lib/raid6/Makefile > >> +++ b/lib/raid6/Makefile > >> @@ -18,6 +18,21 @@ quiet_cmd_unroll = UNROLL $@ > >> > >> ifeq ($(CONFIG_ALTIVEC),y) > >> altivec_flags := -maltivec $(call cc-option,-mabi=altivec) > >> + > >> +ifdef CONFIG_CC_IS_CLANG > > > > Note that the top level makefile detects clang via: > > > > ifeq ($(cc-name),clang) > > > > Does that not work here? I'd prefer to keep compiler detection in > > Makefiles consistent, if it works? > > cc-name is being removed in favor of CONFIG_CC_IS_CLANG: > > https://lore.kernel.org/lkml/1540905994-6073-1-git-send-email-yamada.masahiro@socionext.com/ > > cheers Cool, thanks for the link! -- Thanks, ~Nick Desaulniers
diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile index 2f8b61dfd9b0..3a844e6fd01c 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 -maltifec 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 endif # The GCC option -ffreestanding is required in order to compile code containing