4.4-stable review patch. If anyone has any objections, please let me know.
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From: Arnd Bergmann arnd@arndb.de
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
--- init/Kconfig | 13 +++++++++++++ 1 file changed, 13 insertions(+)
--- a/init/Kconfig +++ b/init/Kconfig @@ -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