PATCH: small -freorder-block defect

[Jason Eckhardt]

we were losing some barriers, which caused problems for delayed branch sched.
acceptable?

	* flow.c (reorder_basic_blocks): Account for barriers when writing
	over NEXT_INSN (last_bb->end).
	(reorder_basic_blocks): Add more sanity checks.


Index: flow.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/flow.c,v
retrieving revision 1.232
diff -c -3 -p -r1.232 flow.c
*** flow.c	2000/03/10 19:21:06	1.232
--- flow.c	2000/03/13 03:08:51
*************** reorder_basic_blocks ()
*** 7758,7765 ****
  	  BASIC_BLOCK (j) = tempbb;
  	}
      }
!       
!   NEXT_INSN (BASIC_BLOCK (n_basic_blocks - 1)->end) = last_insn;
  
    for (i = 0; i < n_basic_blocks - 1; i++)
      {
--- 7758,7787 ----
  	  BASIC_BLOCK (j) = tempbb;
  	}
      }
!      
!     {
!       rtx xafter = skip_insns_between_block (BASIC_BLOCK (n_basic_blocks - 1),
! 					     REORDER_SKIP_AFTER);
!       if (xafter)
! 	NEXT_INSN (xafter) = last_insn;
!       else
! 	abort();
!     }
! 
! #ifdef ENABLE_CHECKING
!   verify_flow_info ();
!     {
!       rtx x;
!       for (x = get_insns(); x; x = NEXT_INSN (x))
! 	{
! 	  if (GET_RTX_CLASS (GET_CODE (x)) == 'i'
! 	      && GET_CODE (x) == JUMP_INSN
! 	      && returnjump_p (x)
! 	      && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
! 	    error ("reorder_basic_blocks: RETURN not followed by BARRIER!\n");
! 	}
!     }
! #endif
  
    for (i = 0; i < n_basic_blocks - 1; i++)
      {