[PATCH 4.19 88/96] Revert "kbuild: use -Oz instead of -Os when using clang"

Greg Kroah-Hartman
2019-04-24T17:46:03Z

commit a75bb4eb9e565b9f5115e2e8c07377ce32cbe69a upstream.

The clang option -Oz enables *aggressive* optimization for size,
which doesn't necessarily result in smaller images, but can have
negative impact on performance. Switch back to the less aggressive
-Os.

This reverts commit 6748cb3c299de1ffbe56733647b01dbcc398c419.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 3fac08f6a11e..91e265ca0ca5 100644
--- a/Makefile
+++ b/Makefile
@@ -661,8 +661,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow)
KBUILD_CFLAGS += $(call cc-disable-warning, int-in-bool-context)

ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-KBUILD_CFLAGS += $(call cc-option,-Oz,-Os)
-KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,)
+KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,)
else
ifdef CONFIG_PROFILE_ALL_BRANCHES
KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,)
--
2.19.1