http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56546
--- Comment #2 from kpet at free dot fr 2013-03-10 17:23:18 UTC --- (In reply to comment #1) > AVR has no divide instruction and / 60 is performed by a multiplication and > some adjustment. Thank you for this explanation. > > gcc-4.7.2, binutils 2.23.1 and avr-libc 1.8.0 give the same result. > > Is this an unpatched avr-gcc? In fact I discovered the issue on a toolchain built with Gentoo's crossdev tool. They are using a good number of patches but these are not the source of the problem. After digging a little deeper I discovered that the problem comes from the build options they use. After a good number of builds on an unpatched gcc-4.7.2 I've been able to determine that the --disable-multilib option they use is the source of the issue. Building with ../configure --prefix=/mnt/work/avr-gentoo-p14-nopie/ --target=avr --enable-languages=c,c++ --disable-nls --disable-libssp --with-dwarf2 gives a toolchain that does not have the issue reported, whereas building with ../configure --prefix=/mnt/work/avr-gentoo-p14-nopie/ --target=avr --enable-languages=c,c++ --disable-nls --disable-libssp --with-dwarf2 --disable-multilib allows to reproduce the issue. I don't know if building with --disable-multilib is correct and am not sure anymore this is an upstream bug...
