https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94311
--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> --- When I put a breakpoint on ../../libcpp/line-map.c:1737 with xloc.line > 40000 (i.e. near end of linemap_expand_location after xloc.line is set), I see (gdb) p/x line_table->highest_line $16 = 0x66e48c7c (gdb) p/x line_table->highest_location $17 = 0x66e48c7c (gdb) p/x loc $18 = 0x6894a440 in the caller during final notice_source_line -> insn_location -> expand_location. I guess I should use -fdump-ipa-cp-lineno to catch it earlier than during final, anyway, having loc higher than highest_location seems very wrong.
