https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67540
--- Comment #3 from Vittorio Zecca <zeccav at gmail dot com> --- I believe the test case is erroneous. NULL pointers are dereferenced in subroutines source_check and source_check4: if(str4 == '12a56b78') call abort() and if(str4 == 4_'12a56b78') call abort() are dereferencing the null pointer str4 and this goes down to string_intrinsics_inc.c There are more test cases with lvz==0. If you had a sanitized version of libgfortran you could check them by yourself.