[PATCH] raid6/ppc: Fix build for clang

From: Joel Stanley
Date: Tue Oct 30 2018 - 23:28:43 EST

We cannot build these files with clang as it does not allow altivec
instructions in assembly when -msoft-float is passed.

Jinsong Ji <jji@xxxxxxxxxx> 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@xxxxxxxxx>
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)
+# 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

# The GCC option -ffreestanding is required in order to compile code containing