https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115968
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- See C++11 and the auto keyword section of https://eigen.tuxfamily.org/dox/TopicPitfalls.html The problem is that eval() returns a temporary object (in this case a MatrixXd) which is then referenced by the Transpose<> expression. However, this temporary is deleted right after the first line, and then the C expression references a dead object.
