| Message ID | 1455293187-179811-3-git-send-email-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Feb 12, 2016 at 05:06:19PM +0100, Arnd Bergmann wrote: > CONFIG_PROFILE_ALL_BRANCHES confuses gcc-5.x to the degree that it prints > incorrect warnings about a lot of variables that it thinks can be used > uninitialized, e.g.: > > i2c/busses/i2c-diolan-u2c.c: In function 'diolan_usb_xfer': > i2c/busses/i2c-diolan-u2c.c:391:16: warning: 'byte' may be used uninitialized in this function > iio/gyro/itg3200_core.c: In function 'itg3200_probe': > iio/gyro/itg3200_core.c:213:6: warning: 'val' may be used uninitialized in this function > leds/leds-lp55xx-common.c: In function 'lp55xx_update_bits': > leds/leds-lp55xx-common.c:350:6: warning: 'tmp' may be used uninitialized in this function > misc/bmp085.c: In function 'show_pressure': > misc/bmp085.c:363:10: warning: 'pressure' may be used uninitialized in this function > power/ds2782_battery.c: In function 'ds2786_get_capacity': > power/ds2782_battery.c:214:17: warning: 'raw' may be used uninitialized in this function > > These are all false positives that either rob someone's time when trying > to figure out whether they are real, or they get people to send wrong > patches to shut up the warnings. > > Nobody normally wants to run a CONFIG_PROFILE_ALL_BRANCHES kernel in > production, so disabling the whole class of warnings for this configuration > has no serious downsides either. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Steven Rostedt <rostedt@goodmis.org> -- Steve > --- > Makefile | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/Makefile b/Makefile > index 9092c16fa6cf..352f55ccc54e 100644 > --- a/Makefile > +++ b/Makefile > @@ -617,7 +617,11 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) > ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) > else > -KBUILD_CFLAGS += -O2 > +ifdef CONFIG_PROFILE_ALL_BRANCHES > +KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) > +else > +KBUILD_CFLAGS += -O2 > +endif > endif > > # Tell gcc to never replace conditional load with a non-conditional one > -- > 2.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Makefile b/Makefile index 9092c16fa6cf..352f55ccc54e 100644 --- a/Makefile +++ b/Makefile @@ -617,7 +617,11 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) else -KBUILD_CFLAGS += -O2 +ifdef CONFIG_PROFILE_ALL_BRANCHES +KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) +else +KBUILD_CFLAGS += -O2 +endif endif # Tell gcc to never replace conditional load with a non-conditional one
CONFIG_PROFILE_ALL_BRANCHES confuses gcc-5.x to the degree that it prints incorrect warnings about a lot of variables that it thinks can be used uninitialized, e.g.: i2c/busses/i2c-diolan-u2c.c: In function 'diolan_usb_xfer': i2c/busses/i2c-diolan-u2c.c:391:16: warning: 'byte' may be used uninitialized in this function iio/gyro/itg3200_core.c: In function 'itg3200_probe': iio/gyro/itg3200_core.c:213:6: warning: 'val' may be used uninitialized in this function leds/leds-lp55xx-common.c: In function 'lp55xx_update_bits': leds/leds-lp55xx-common.c:350:6: warning: 'tmp' may be used uninitialized in this function misc/bmp085.c: In function 'show_pressure': misc/bmp085.c:363:10: warning: 'pressure' may be used uninitialized in this function power/ds2782_battery.c: In function 'ds2786_get_capacity': power/ds2782_battery.c:214:17: warning: 'raw' may be used uninitialized in this function These are all false positives that either rob someone's time when trying to figure out whether they are real, or they get people to send wrong patches to shut up the warnings. Nobody normally wants to run a CONFIG_PROFILE_ALL_BRANCHES kernel in production, so disabling the whole class of warnings for this configuration has no serious downsides either. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- Makefile | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)