On Tue, Mar 23, 2021 at 02:20:23PM +0100, Arnd Bergmann wrote: > From: Arnd Bergmann <a...@arndb.de> > > Passing an 8-bit constant into delay() triggers a warning when building > with 'make W=1' using clang: > > drivers/clk/actions/owl-pll.c:182:2: error: result of comparison of constant > 2000 with expression of type 'u8' (aka 'unsigned char') is always false > [-Werror,-Wtautological-constant-out-of-range-compare] > udelay(pll_hw->delay); > ^~~~~~~~~~~~~~~~~~~~~ > arch/arm/include/asm/delay.h:84:9: note: expanded from macro 'udelay' > ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \ > ~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~ > arch/arm/mach-omap2/wd_timer.c:89:3: error: result of comparison of constant > 2000 with expression of type 'u8' (aka 'unsigned char') is always false > [-Werror,-Wtautological-constant-out-of-range-compare] > udelay(oh->class->sysc->srst_udelay); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Shut up the warning by adding a cast to a 64-bit number. A cast to 'int' > would usually be sufficient, but would fail to cause a link-time error > for large 64-bit constants.
What effect (if any) does this have on code generation when the argument is not constant? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
