https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66223
--- Comment #2 from Daniel Frey <d.frey at gmx dot de> --- I'm using Ubuntu 14.04 in a VM, packages are installed from http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu trusty main. Package version is 5.1.0-0ubuntu11~14.04.1 Output from g++-5 -v: Using built-in specs. COLLECT_GCC=g++-5 COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/5/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 5.1.0-0ubuntu11~14.04.1' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs --enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-5 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=c++98 --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 5.1.0 (Ubuntu 5.1.0-0ubuntu11~14.04.1) I'm compiling the example code with: g++-5 -std=c++14 -O3 -Wall -Wextra t.cpp I tried it without -O3 and it then prints the old output: pure virtual method called terminate called without an active exception Aborted (core dumped) So that probably means it has something to do with the optimizer?