https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101574
--- Comment #8 from Martin Sebor <msebor at gcc dot gnu.org> --- The symptom in comment #6 does look similar to the problem discussed in pr101292. I haven't debugged it yet but when developing the warning control patch I struggled with keeping the garbage collector from collecting the global hash map between location_t and the nowarn_spec_t struct. My suspicion is that either the annotation on the hash_map isn't correct (it's a simple GTY("") so it's hard to imagine what might be wrong with it), or the integration with the garbage collector is incomplete (I had to change the hash_map definition itself to let hash_map<location_t, nowarn_spec_t> even compile).