[patch, commited] Fix loop updating in split_block

[patch, commited] Fix loop updating in split_block

[Zdenek Dvorak]

Hello,

when we split a latch block of a loop, the newly created block becomes
the new latch of the loop.  This patch makes us update the information
about the loop to reflect this.

Bootstrapped & regtested on i686, commited.

Zdenek

	* cfghooks.c (split_block): Fix the information about loop latch.

Index: cfghooks.c
===================================================================
*** cfghooks.c	(revision 126869)
--- cfghooks.c	(working copy)
*************** split_block (basic_block bb, void *i)
*** 432,438 ****
      }
  
    if (current_loops != NULL)
!     add_bb_to_loop (new_bb, bb->loop_father);
  
    return make_single_succ_edge (bb, new_bb, EDGE_FALLTHRU);
  }
--- 432,442 ----
      }
  
    if (current_loops != NULL)
!     {
!       add_bb_to_loop (new_bb, bb->loop_father);
!       if (bb->loop_father->latch == bb)
! 	bb->loop_father->latch = new_bb;
!     }
  
    return make_single_succ_edge (bb, new_bb, EDGE_FALLTHRU);
  }