https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108086
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> --- Ick. gcc/rtl-ssa/insns.h: unsigned int m_num_defs : 16; (gdb) p num_defs $1 = 86149 (gdb) p m_num_defs $2 = 20613 (gdb) p m_rtl $3 = (rtx_insn *) 0x0 (gdb) p is_phi () $4 = false (gdb) p is_bb_head () $5 = false (gdb) p is_artificial () $7 = true m_bb is for ENTRY and for some reason that has a very big live-out bitmap?! There might be a conservative way to handle this and not blow up where it does right now?