| Message ID | 20200107204300.1365789-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | input: appletouch: shut up -Wmaybe-uninitialized warning | expand |
Hi Arnd, On Tue, Jan 07, 2020 at 09:42:45PM +0100, Arnd Bergmann wrote: > Building with -O3 introduces a false-positive warning in this file: > > In file included from include/linux/compiler_types.h:68, > from <command-line>: > drivers/input/mouse/appletouch.c: In function 'atp_complete_geyser_3_4': > include/linux/compiler-gcc.h:71:45: error: 'x_z' may be used uninitialized in this function [-Werror=maybe-uninitialized] > #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) > ^~~~~~~~~~~~ > drivers/input/mouse/appletouch.c:657:12: note: 'x_z' was declared here > int x, y, x_z, y_z, x_f, y_f; > ^~~ > In file included from include/linux/compiler_types.h:68, > from <command-line>: > drivers/input/mouse/appletouch.c: In function 'atp_complete_geyser_1_2': > include/linux/compiler-gcc.h:71:45: error: 'x_z' may be used uninitialized in this function [-Werror=maybe-uninitialized] > #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) > ^~~~~~~~~~~~ > drivers/input/mouse/appletouch.c:517:12: note: 'x_z' was declared here > int x, y, x_z, y_z, x_f, y_f; > ^~~ > > The variables are not actually used here since the only usage > happens when both 'x' and 'y' are non-zero, but this is something > that gcc fails to track. > > Fixes: mmtom ("init/Kconfig: enable -O3 for all arches") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/input/mouse/appletouch.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c > index 3f06e8a495d8..ec2139c43fcd 100644 > --- a/drivers/input/mouse/appletouch.c > +++ b/drivers/input/mouse/appletouch.c > @@ -330,7 +330,7 @@ static void atp_reinit(struct work_struct *work) > retval); > } > > -static int atp_calculate_abs(struct atp *dev, int offset, int nb_sensors, > +static noinline int atp_calculate_abs(struct atp *dev, int offset, int nb_sensors, > int fact, int *z, int *fingers) I wonder if instead of nolinine we can have "*fingers = *z = 0;" in this function... I feel noinline has to be reserved for exceptional cases... Thanks.
diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c index 3f06e8a495d8..ec2139c43fcd 100644 --- a/drivers/input/mouse/appletouch.c +++ b/drivers/input/mouse/appletouch.c @@ -330,7 +330,7 @@ static void atp_reinit(struct work_struct *work) retval); } -static int atp_calculate_abs(struct atp *dev, int offset, int nb_sensors, +static noinline int atp_calculate_abs(struct atp *dev, int offset, int nb_sensors, int fact, int *z, int *fingers) { int i, pass;
Building with -O3 introduces a false-positive warning in this file: In file included from include/linux/compiler_types.h:68, from <command-line>: drivers/input/mouse/appletouch.c: In function 'atp_complete_geyser_3_4': include/linux/compiler-gcc.h:71:45: error: 'x_z' may be used uninitialized in this function [-Werror=maybe-uninitialized] #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) ^~~~~~~~~~~~ drivers/input/mouse/appletouch.c:657:12: note: 'x_z' was declared here int x, y, x_z, y_z, x_f, y_f; ^~~ In file included from include/linux/compiler_types.h:68, from <command-line>: drivers/input/mouse/appletouch.c: In function 'atp_complete_geyser_1_2': include/linux/compiler-gcc.h:71:45: error: 'x_z' may be used uninitialized in this function [-Werror=maybe-uninitialized] #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) ^~~~~~~~~~~~ drivers/input/mouse/appletouch.c:517:12: note: 'x_z' was declared here int x, y, x_z, y_z, x_f, y_f; ^~~ The variables are not actually used here since the only usage happens when both 'x' and 'y' are non-zero, but this is something that gcc fails to track. Fixes: mmtom ("init/Kconfig: enable -O3 for all arches") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/input/mouse/appletouch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)