https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101135
--- Comment #1 from Marcel Jacobse <marcel.jacobse at ewetel dot net> --- With some bisecting I managed to track this down to commit https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=243c288370fe51ba55c3a9ee61eb2a1a62cb1279 being the first "faulty" one. >From what I can tell the commit aimed to catch null pointer dereferences in more cases. Not sure if this means that the commit made the check to broad so that it generates false positives for this Fortran case. Or if gfortran perhaps generates intermediate representation that is not quite valid and is correctly flagged by UBSan.
