https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86828
--- Comment #9 from janus at gcc dot gnu.org --- (In reply to Richard Biener from comment #8) > More details are needed here. What exactly do you need? $ gfortran-7 -march=knl -Ofast -g c0.f90 $ gdb ./a.out [..] (gdb) run Starting program: /home/janus/fort/gfortran_bugs/86828_knl/a.out Program received signal SIGSEGV, Segmentation fault. s (n=..., n=...) at c0.f90:26 26 liKOB = Y(n%list) (gdb) bt #0 s (n=..., n=...) at c0.f90:26 #1 0x0000555555554a9b in knl_bug () at c0.f90:17 #2 main (argc=argc@entry=1, argv=0x7fffffffe53a) at c0.f90:17 #3 0x00007ffff7626b97 in __libc_start_main (main=0x555555554800 <main>, argc=1, argv=0x7fffffffe298, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe288) at ../csu/libc-start.c:310 #4 0x0000555555554bca in _start ()