kbuild: use -Oz instead of -Os when using clang

This generates smaller resulting object code when compiled with clang.

Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index ae49fef98ca3..d26618608633 100644
--- a/Makefile
+++ b/Makefile
@@ -638,7 +638,8 @@ KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
 endif
 
 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-KBUILD_CFLAGS   += -Os $(call cc-disable-warning,maybe-uninitialized,)
+KBUILD_CFLAGS   += $(call cc-option,-Oz,-Os)
+KBUILD_CFLAGS   += $(call cc-disable-warning,maybe-uninitialized,)
 else
 ifdef CONFIG_PROFILE_ALL_BRANCHES
 KBUILD_CFLAGS   += -O2 $(call cc-disable-warning,maybe-uninitialized,)