On Sat, Aug 12, 2023 at 5:00 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > > From: Arnd Bergmann <arnd@xxxxxxxx> > > The warning does nothing for newer versions of gcc since -fno-strict-overflow > is used, on old versions it warns about lines that would be undefined > otherwise: > > fs/isofs/util.c: In function 'iso_date': > fs/isofs/util.c:40:14: error: left shift of negative value [-Werror=shift-negative-value] > tz |= (-1 << 8); > ^~ > drivers/video/fbdev/tdfxfb.c: In function 'tdfxfb_probe': > drivers/video/fbdev/tdfxfb.c:1482:17: error: left shift of negative value [-Werror=shift-negative-value] > (PAGE_MASK << 1); > ^~ > drivers/tty/serial/8250/8250_core.c: In function 'serial8250_request_rsa_resource': > drivers/tty/serial/8250/8250_core.c:350:38: error: left shift of negative value [-Werror=shift-negative-value] > unsigned long start = UART_RSA_BASE << up->port.regshift; > ^~ > drivers/tty/serial/8250/8250_core.c: In function 'serial8250_release_rsa_resource': > drivers/tty/serial/8250/8250_core.c:371:39: error: left shift of negative value [-Werror=shift-negative-value] > unsigned long offset = UART_RSA_BASE << up->port.regshift; > ^~ > drivers/clk/mvebu/dove-divider.c: In function 'dove_set_clock': > drivers/clk/mvebu/dove-divider.c:145:14: error: left shift of negative value [-Werror=shift-negative-value] > mask = ~(~0 << dc->div_bit_size) << dc->div_bit_start; > ^~ > drivers/block/drbd/drbd_main.c: In function 'dcbp_set_pad_bits': > drivers/block/drbd/drbd_main.c:1098:37: error: left shift of negative value [-Werror=shift-negative-value] > p->encoding = (p->encoding & (~0x7 << 4)) | (n << 4); > > Disable these conditionally to keep the command line a little shorter. Just a nit for the commit subject and description. It mentions only gcc, but also affects clang. Is the following a better subject? extrawarn: don't turn off -Wshift-negative-value for gcc-9+ or clang or extrawarn: turn off -Wshift-negative-value only for gcc < 9 -- Best Regards Masahiro Yamada
