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Kbuild: change CC_OPTIMIZE_FOR_SIZE definition

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commit 877417e6ffb9578e8580abf76a71e15732473456 upstream.

CC_OPTIMIZE_FOR_SIZE disables the often useful -Wmaybe-unused warning,
because that causes a ridiculous amount of false positives when combined
with -Os.

This means a lot of warnings don't show up in testing by the developers
that should see them with an 'allmodconfig' kernel that has
CC_OPTIMIZE_FOR_SIZE enabled, but only later in randconfig builds
that don't.

This changes the Kconfig logic around CC_OPTIMIZE_FOR_SIZE to make
it a 'choice' statement defaulting to CC_OPTIMIZE_FOR_PERFORMANCE
that gets added for this purpose. The allmodconfig and allyesconfig
kernels now default to -O2 with the maybe-unused warning enabled.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Marek <mmarek@suse.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Arnd Bergmann 2016-04-25 17:35:27 +02:00 committed by Greg Kroah-Hartman
parent e88640adf6
commit ffe4bf3eb3
1 changed files with 13 additions and 0 deletions
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13
init/Kconfig
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@ -1308,6 +1308,17 @@ source "usr/Kconfig"
endif
choice
prompt "Compiler optimization level"
default CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
config CC_OPTIMIZE_FOR_PERFORMANCE
bool "Optimize for performance"
help
This is the default optimization level for the kernel, building
with the "-O2" compiler flag for best performance and most
helpful compile-time warnings.
config CC_OPTIMIZE_FOR_SIZE
bool "Optimize for size"
help
@ -1316,6 +1327,8 @@ config CC_OPTIMIZE_FOR_SIZE
If unsure, say N.
endchoice
config SYSCTL
bool