[Bug analyzer/113314] New: -Wanalyzer-infinite-loop false positive seen on haproxy's fd.c

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113314

            Bug ID: 113314
           Summary: -Wanalyzer-infinite-loop false positive seen on
                    haproxy's fd.c
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: dmalcolm at gcc dot gnu.org
  Target Milestone: ---

Created attachment 57027
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57027&action=edit
Reproducer

https://godbolt.org/z/1oYYear8z

t.c: In function ‘fd_add_to_fd_list’:
t.c:71:15: warning: infinite loop [CWE-835] [-Wanalyzer-infinite-loop]
   71 |   next = fdtab[fd].update.next;
      |               ^
  ‘fd_add_to_fd_list’: events 1-5
    |
    |   71 |   next = fdtab[fd].update.next;
    |      |               ^
    |      |               |
    |      |               (1) infinite loop here
    |   72 |   if (next > -2)
    |      |      ~         
    |      |      |
    |      |      (2) if it ever follows ‘false’ branch, it will always do
so...
    |   73 |     goto done;
    |   74 |   if (next == -2)
    |      |      ~         
    |      |      |
    |      |      (3) ...to here
    |      |      (4) if it ever follows ‘true’ branch, it will always do so...
    |   75 |     goto redo_next;
    |      |     ~~~~       
    |      |     |
    |      |     (5) ...to here
    |
  ‘fd_add_to_fd_list’: event 6
    |
    |cc1:
    | (6): looping back...
    |
  ‘fd_add_to_fd_list’: event 7
    |
    |   71 |   next = fdtab[fd].update.next;
    |      |               ^
    |      |               |
    |      |               (7) ...to here

Seen on haproxy-2.7.1's src/fd.c (in analyzer integration tests).