[4.0/mainline] PR 21562

[Jan Hubicka]

> > On Fri, May 27, 2005 at 02:18:21AM +0200, Jan Hubicka wrote:
> > > !       if (!(e2->flags & EDGE_ABNORMAL))
> > > !       {
> > > ! 	/* Multiple entry points not supported yet.  */
> > > ! 	gcc_assert (!e);
> > >   	e = e2;
> > 
> > Under what conditions are you seeing EDGE_ABNORMAL from ENTRY?
> 
> I guess I don't.  I somehow believe that it is how multiple return
> functions (setjmp) are represented but they are not.  I think I did it
> in my tree once in the past tought.
> I am re-testing the patch without this check.
OK, here is updated patch.

Index: cfgexpand.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cfgexpand.c,v
retrieving revision 2.39
diff -c -3 -p -r2.39 cfgexpand.c
*** cfgexpand.c	19 May 2005 03:05:38 -0000	2.39
--- cfgexpand.c	28 May 2005 00:01:35 -0000
*************** static basic_block
*** 1157,1178 ****
  construct_init_block (void)
  {
    basic_block init_block, first_block;
!   edge e = NULL, e2;
!   edge_iterator ei;
  
!   FOR_EACH_EDGE (e2, ei, ENTRY_BLOCK_PTR->succs)
!     {
!       /* Clear EDGE_EXECUTABLE.  This flag is never used in the backend.
  
! 	 For all other blocks this edge flag is cleared while expanding
! 	 a basic block in expand_gimple_basic_block, but there we never
! 	 looked at the successors of the entry block.
! 	 This caused PR17513.  */
!       e2->flags &= ~EDGE_EXECUTABLE;
  
!       if (e2->dest == ENTRY_BLOCK_PTR->next_bb)
! 	e = e2;
      }
  
    init_block = create_basic_block (NEXT_INSN (get_insns ()),
  				   get_last_insn (),
--- 1157,1181 ----
  construct_init_block (void)
  {
    basic_block init_block, first_block;
!   edge e = NULL;
!   int flags;
  
!   /* Multiple entry points not supported yet.  */
!   gcc_assert (EDGE_COUNT (ENTRY_BLOCK_PTR->succs) == 1);
  
!   e = EDGE_SUCC (ENTRY_BLOCK_PTR, 0);
  
!   /* When entry edge points to first basic block, we don't need jump,
!      otherwise we have to jump into proper target.  */
!   if (e && e->dest != ENTRY_BLOCK_PTR->next_bb)
!     {
!       tree label = tree_block_label (e->dest);
! 
!       emit_jump (label_rtx (label));
!       flags = 0;
      }
+   else
+     flags = EDGE_FALLTHRU;
  
    init_block = create_basic_block (NEXT_INSN (get_insns ()),
  				   get_last_insn (),
*************** construct_init_block (void)
*** 1183,1189 ****
      {
        first_block = e->dest;
        redirect_edge_succ (e, init_block);
!       e = make_edge (init_block, first_block, EDGE_FALLTHRU);
      }
    else
      e = make_edge (init_block, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
--- 1186,1192 ----
      {
        first_block = e->dest;
        redirect_edge_succ (e, init_block);
!       e = make_edge (init_block, first_block, flags);
      }
    else
      e = make_edge (init_block, EXIT_BLOCK_PTR, EDGE_FALLTHRU);