[Bug tree-optimization/113374] [14 regression] ICE in find_uses_to_rename_use

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
The code populating alternative exit virtual PHIs simply doesn't handle more
than one arg ...

          /* Now link the alternative exits.  */
          if (multiple_exits_p)  
            {
...
                       SET_PHI_ARG_DEF (l_phi, 0, exit_val);

we're losing the original ones doing

      for (auto exit : loop_exits)
        {       
          basic_block dest = main_loop_exit_block;
          if (exit != loop_exit)
            {
              if (!alt_loop_exit_block)
                { 
                  edge res = redirect_edge_and_branch ( 
                                exit,
                                new_preheader);
                  flush_pending_stmts (res);
                  alt_loop_exit_block = split_edge (res);
                  continue;
                }
              dest = alt_loop_exit_block;
            }
          edge e = redirect_edge_and_branch (exit, dest);
          flush_pending_stmts (e);
        }

since that creates a new BB without any virtual PHI.