Re: cfg_cleanup and loop discovery in cfg_layout mode

[Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>]

Hello,

> > On Thu, Jul 03, 2003 at 10:39:26AM +0200, Jan Hubicka wrote:
> > > http://gcc.gnu.org/ml/gcc-patches/2003-06/msg01741.html
> > 
> > Ok.
> 
> Thanks!  I've updated all the patches for ISO-C prototypes and installed
> them together (they are too interwinded to be reliably tested
> separately)

this should fix the breakage the patches caused on
powerpc-apple-darwin6.3.  The problem was that the original code
removes the label if it occurs in bb 0.

I don't fully understand what Honza wanted the code to do, especially
why he is handling the case when NOTE_INSN_BASIC_BLOCK comes first
specially; but I believe this one should work as well.

Zdenek

	* cfglayout.c (record_effective_endpoints): Split insns before
	first basic block correctly.

Index: cfglayout.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cfglayout.c,v
retrieving revision 1.41
diff -c -3 -p -r1.41 cfglayout.c
*** cfglayout.c	3 Jul 2003 23:50:05 -0000	1.41
--- cfglayout.c	4 Jul 2003 21:28:16 -0000
*************** record_effective_endpoints (void)
*** 196,214 ****
    rtx insn;
  
    for (insn = get_insns ();
!        NEXT_INSN (insn) && GET_CODE (insn) == NOTE;
         insn = NEXT_INSN (insn))
!     {
!       if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK)
! 	{
! 	  insn = NULL;
! 	  break;
! 	 }
!       if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
! 	break;
!     }
!   if (insn)
!     cfg_layout_function_header = unlink_insn_chain (get_insns (), insn);
    else
      cfg_layout_function_header = NULL_RTX;
  
--- 196,211 ----
    rtx insn;
  
    for (insn = get_insns ();
!        insn
!        && GET_CODE (insn) == NOTE
!        && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK;
         insn = NEXT_INSN (insn))
!     continue;
!   if (!insn)
!     abort ();  /* No basic blocks at all?  */
!   if (PREV_INSN (insn))
!     cfg_layout_function_header =
! 	    unlink_insn_chain (get_insns (), PREV_INSN (insn));
    else
      cfg_layout_function_header = NULL_RTX;