[Bug tree-optimization/64284] [5 Regression] ICE: Segmentation fault

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64284

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-12-12
                 CC|                            |spop at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
  Registering jump thread: (4, 5) incoming edge;  (5, 55) joiner;  (55, 63)
normal;
  Registering FSM jump thread: (94, 5) incoming edge;  (6, 20) nocopy;
  Registering jump thread: (61, 6) incoming edge;  (6, 20) normal;
  Registering jump thread: (77, 6) incoming edge;  (6, 20) normal;
  Registering jump thread: (69, 6) incoming edge;  (6, 20) normal;
  Registering FSM jump thread: (94, 5) incoming edge;  (55, 56) nocopy;
...
  Threaded jump 69 --> 6 to 109
  Threaded jump 77 --> 6 to 109
  Threaded jump 61 --> 6 to 109

and then we end up with an invalid loop.  FSM threads the latch edge but
doesn't update the loop structure accordingly so later asking for the
loop latch edge fails (because the loop isn't anymore it seems - or
header and latch are no longer valid).

Let me have a look.