[CFG] cfg_layout_duplicate_bb patch

[Jan Hubicka]

> Hello.
> 
> This patch fixes bug in cfg_layout_duplicate_bb when duplicating empty
> basic block.
> 
> Zdenek Dvorak
> 
> 	* cfglayout.c (cfg_layout_duplicate_bb): Modified.
INstalled, thanks!

Honza
> 
> Index: cfglayout.c
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/cfglayout.c,v
> retrieving revision 1.2.2.35
> diff -c -3 -p -r1.2.2.35 cfglayout.c
> *** cfglayout.c	2002/02/19 11:53:35	1.2.2.35
> --- cfglayout.c	2002/02/21 11:49:26
> *************** cfg_layout_duplicate_bb (bb, e)
> *** 848,855 ****
>   #endif
>   
>     insn = duplicate_insn_chain (bb->head, bb->end);
> !   new_bb = create_basic_block (n_basic_blocks, insn ? insn : get_last_insn (),
> ! 		 	       get_last_insn ());
>     alloc_aux_for_block (new_bb, sizeof (struct reorder_block_def));
>   
>     if (RBI (bb)->header)
> --- 848,855 ----
>   #endif
>   
>     insn = duplicate_insn_chain (bb->head, bb->end);
> !   new_bb = create_basic_block (n_basic_blocks, insn,
> ! 		 	       insn ? get_last_insn () : NULL);
>     alloc_aux_for_block (new_bb, sizeof (struct reorder_block_def));
>   
>     if (RBI (bb)->header)