https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64717
--- Comment #2 from Gert-jan Los <gerrit.los at gmail dot com> --- Created attachment 34616 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34616&action=edit test case with virtual base class version: gcc version 5.0.0 20150128 (experimental) (GCC) options: -O -fsanitize=vptr -Werror=uninitialized gap_widths.C.i: In function ‘void fn1()’: gap_widths.C.i:13:41: error: ‘<anonymous>’ is used uninitialized in this function [-Werror=uninitialized]