http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58678
--- Comment #27 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- (In reply to David Kredba from comment #26) > Hello Markus, > Could you kindly please write here how are you reducing this? > > (So next time I can try to do it myself.) Sure. First thing is to find out which object files contains these undefined symbols. cd /var/tmp/portage/kde-base/korganizer-4.12.3 for f in **/*.o ; do echo $f && nm $f | c++filt | grep "KParts::Part::~Part()" ; done This will point to kocore.o. Then lookup how kocore.o was compiled in the build.log. Add --save-temps to the invocation. Write a check.sh script for creduce, e.g. something like: % cat check.sh #!/bin/sh /usr/x86_64-pc-linux-gnu/gcc-bin/4.8.3/g++ -Wall -Wextra -c -O2 -Werror -Wfatal-errors -c test.ii -pipe if ! test $? = 0; then exit 1 fi nm test.o | grep _ZN6KParts4PartD0Ev if test $? = 0; then exit 1 fi g++ -Wall -Wextra -c -O2 -Werror -Wfatal-errors test.ii -pipe if ! test $? = 0; then exit 1 fi nm test.o | grep _ZN6KParts4PartD0Ev if ! test $? = 0; then exit 1 fi And finally run creduce.