[Bug rtl-optimization/57662] [4.9 Regression] ICE: SIGSEGV in code_motion_process_successors with -fschedule-insns2 -fselective-scheduling2

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57662

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
In sel-sched.c,
      /* We have simplified the control flow below this point.  In this case,
         the iterator becomes invalid.  We need to try again.  */
      if (BLOCK_FOR_INSN (insn)->index != old_index
          || EDGE_COUNT (bb->succs) != old_succs)
the BLOCK_FOR_INSN (insn) is NULL, so we segfault; the call to
code_motion_path_driver somehow changes the insn to
(jump_insn/v 203 0 0 (set (pc)
        (label_ref 202)) -1
     (nil)
 -> 202)