https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64078
--- Comment #12 from Bernd Edlinger <bernd.edlinger at hotmail dot de> --- The same could happen also with object-size-10.c: https://gcc.gnu.org/ml/gcc-testresults/2015-04/msg01293.html FAIL: c-c++-common/ubsan/object-size-10.c -O2 execution test FAIL: c-c++-common/ubsan/object-size-10.c -O2 -flto -fno-use-linker-plugin -flto-partition=none execution test I can't reproduce that one, but it may possibly also be a pointer value too close to a page boundary?