[PATCH 4.9 20/59] x86/kbuild: Use cc-option to enable -falign-{jumps/loops}

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matthias Kaehlcke <mka@xxxxxxxxxxxx>

commit 2c4fd1ac3ff167c91272dc43c7bfd2269ef61557 upstream.

clang currently does not support these optimizations, only enable them
when they are available.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Cc: Greg Hackmann <ghackmann@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Michael Davidson <md@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: grundler@xxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20170413172609.118122-1-mka@xxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/x86/Makefile |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -88,10 +88,10 @@ else
         KBUILD_CFLAGS += -m64
 
         # Align jump targets to 1 byte, not the default 16 bytes:
-        KBUILD_CFLAGS += -falign-jumps=1
+        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
 
         # Pack loops tightly as well:
-        KBUILD_CFLAGS += -falign-loops=1
+        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
 
         # Don't autogenerate traditional x87 instructions
         KBUILD_CFLAGS += $(call cc-option,-mno-80387)