[PATCH] Kbuild: x86: Eliminate duplicate command line options

From: Rasmus Villemoes
Date: Tue Aug 05 2014 - 12:17:49 EST


The options -mno-mmx and -mno-sse are unconditionally added to
KBUILD_CFLAGS in both branches of an ifeq and through a $(cc-option)
further down. We can safely remove the first instances.

In fact, since the -mno-mmx and -mno-sse options were introduced
simultaneous with the other two options in the $(cc-option) [according
to http://www.gnu.org/software/gcc/gcc-3.1/changes.html], and since
the former were unconditionally used, one can deduce that only gcc
versions knowing about all four are supported. So also eliminate the
$(cc-option) wrap.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
arch/x86/Makefile | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index c65fd96..202f849 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -50,9 +50,6 @@ ifeq ($(CONFIG_X86_32),y)

KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return

- # Don't autogenerate MMX or SSE instructions
- KBUILD_CFLAGS += -mno-mmx -mno-sse
-
# Never want PIC in a 32-bit kernel, prevent breakage with GCC built
# with nonstandard options
KBUILD_CFLAGS += -fno-pic
@@ -80,8 +77,7 @@ else
KBUILD_AFLAGS += -m64
KBUILD_CFLAGS += -m64

- # Don't autogenerate traditional x87, MMX or SSE instructions
- KBUILD_CFLAGS += -mno-mmx -mno-sse
+ # Don't autogenerate traditional x87 instructions
KBUILD_CFLAGS += $(call cc-option,-mno-80387)
KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)

@@ -168,7 +164,7 @@ KBUILD_CFLAGS += -Wno-sign-compare
#
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# prevent gcc from generating any FP code by mistake
-KBUILD_CFLAGS += $(call cc-option,-mno-sse -mno-mmx -mno-sse2 -mno-3dnow,)
+KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
KBUILD_CFLAGS += $(call cc-option,-mno-avx,)

KBUILD_CFLAGS += $(mflags-y)
--
1.9.2

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