On Sun, Sep 09, 2012 at 10:38:41PM +0200, Geert Uytterhoeven wrote: > Hi Günter, > > On Sun, Sep 9, 2012 at 6:17 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > On Sun, Sep 09, 2012 at 04:57:34PM +0200, Geert Uytterhoeven wrote: > >> On Fri, Aug 31, 2012 at 5:02 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > >> > DIV_ROUND_CLOSEST returns a bad result for negative dividends: > >> > DIV_ROUND_CLOSEST(-2, 2) = 0 > >> > > >> > Most of the time this does not matter. However, in the hardware monitoring > >> > subsystem, DIV_ROUND_CLOSEST is sometimes used on integers which can be > >> > negative (such as temperatures). > >> > >> This seems to cause 3 new warnings in my m68k builds of v3.6-rc5: > >> > >> drivers/hwmon/mcp3021.c:76: warning: comparison is always true due to > >> limited range of data type > >> drivers/ide/ide-cd.c:1158: warning: comparison is always true due to > >> limited range of data type > >> drivers/ide/ide-cd.c:1159: warning: comparison is always true due to > >> limited range of data type > >> > >> $ m68k-linux-gnu-gcc -v > >> Using built-in specs. > >> Target: m68k-linux-gnu > >> Configured with: ../src/configure -v --enable-languages=c,c++ > >> --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib > >> --without-included-gettext --enable-threads=posix --enable-nls > >> --with-gxx-include-dir=/usr/m68k-linux-gnu/include/c++/4.1.2 > >> --program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu > >> --enable-libstdcxx-debug --disable-libssp --disable-werror > >> --enable-checking=release --program-prefix=m68k-linux-gnu- > >> --includedir=/usr/m68k-linux-gnu/include --build=x86_64-linux-gnu > >> --host=x86_64-linux-gnu --target=m68k-linux-gnu > >> Thread model: posix > >> gcc version 4.1.2 20061115 (prerelease) (Ubuntu 4.1.1-21) > >> > > The "always true" condition is on purpose to cause the compiler to optimize the > > expression away. I don't see the warnings myself, on none of the targets I am > > building (x86, ppc, arm, mips), but then I am using much more recent compiler > > versions. Odd is that you only see the warnings on "u16" and not elsewhere. > > > > I don't immediately see the warnings with a more recent m68k compiler (4.6.3), > > nor with any other target (x86, ppc, arm, mips) in my nightly builds. > > I also don't see it in any of the linux-next builds of v3.6-rc5. So > probably it's just > a gcc 4.1.2 issue... > > > Can you send me your configuration ? > > The ide-cd one shows up in any config that enables ide-cd, incl. defconfig and > allmodconfig. > The mcp3021 one I only see in allmodconfig. > I tried both and did not see the problem. I agree, it does look like a compiler version problem. > > Also, do you know where I can find the Ubuntu/Debian package for your compiler > > version, by any chance ? > > It's not from an official binary package. I built the cross-compiler > from the then > current gcc 4.1.1-21 sources in Ubuntu. > Ok. Just in case you are interested, I installed the m68k cross-compiler from deb http://www.freewrt.org/~tg/debs68k/ cross main For my other targets, I use Yocto builds. I think I'll let this go as false positive for now, unless there are problems with more recent compilers. Thanks, Guenter _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
