https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67937
--- Comment #6 from Jan Hubicka <hubicka at gcc dot gnu.org> --- We can have negative counters on fake edges in case the code uses abnormal edges that we can't instrument correctly. setjmp/longjmp is one of examples. If you profile kernel, you will have inconsistencies in profile because of race conditions.
