3.1 Patch Reverse: gcc/flow.c

[Jeffrey Oldham]

The attached patch (applied in reverse for gcc3.1) is Jan Hubicka's
flow.c patch of 02Jul.  The patch causes the test regression for
i686-pc-linux-gnu gcc3.1:

  FAIL: gcc.dg/wtr-label-1.c (test for excess errors)

He promised to fix it after his return
( http://gcc.gnu.org/ml/gcc-patches/2001-07/msg00270.html ).  In the
meantime, we reverse it to avoid difficulties.

2001-07-05  Jeffrey Oldham  <oldham@codesourcery.com>

	* flow.c: Reverse Jan Hubicka's patch of 02July2001.
	(try_redirect_by_replacing_jump): Reverse updating properly the
	count and frequency information.  Reverse removing cc0 setter.
	(forwarder_block_p): Reverse fixing for fallthru blocks.

Applied to	3.1
Tested on	i686-pc-linux-gnu
Approved by	Richard Henderson (rth@redhat.com)

Thanks,
Jeffrey D. Oldham
oldham@codesourcery.com
Index: flow.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/flow.c,v
retrieving revision 1.411
retrieving revision 1.412
diff -c -p -r1.411 -r1.412
*** flow.c	2001/07/02 16:47:57	1.411
--- flow.c	2001/07/02 21:16:48	1.412
*************** static bool
*** 1597,1614 ****
  forwarder_block_p (bb)
       basic_block bb;
  {
!   rtx insn;
    if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR
        || !bb->succ || bb->succ->succ_next)
      return false;
  
!   insn = next_active_insn (bb->head);
!   if (!insn)
!     return false;
!   if (GET_CODE (insn) == CODE_LABEL
!       || (GET_CODE (insn) == JUMP_INSN && onlyjump_p (insn)))
!     return true;
!   return false;
  }
  
  /* Return nonzero if we can reach target from src by falling trought.  */
--- 1597,1615 ----
  forwarder_block_p (bb)
       basic_block bb;
  {
!   rtx insn = bb->head;
    if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR
        || !bb->succ || bb->succ->succ_next)
      return false;
  
!   while (insn != bb->end)
!     {
!       if (active_insn_p (insn))
! 	return false;
!       insn = NEXT_INSN (insn);
!     }
!   return (!active_insn_p (insn)
! 	  || (GET_CODE (insn) == JUMP_INSN && onlyjump_p (insn)));
  }
  
  /* Return nonzero if we can reach target from src by falling trought.  */
*************** try_redirect_by_replacing_jump (e, targe
*** 1699,1704 ****
--- 1700,1707 ----
      e->flags = EDGE_FALLTHRU;
    else
      e->flags = 0;
+   e->probability = REG_BR_PROB_BASE;
+   e->count = src->count;
  
    /* Fixup barriers.  */
    barrier = next_nonnote_insn (insn);
*************** try_redirect_by_replacing_jump (e, targe
*** 1707,1712 ****
--- 1710,1729 ----
    else if (!fallthru && GET_CODE (barrier) != BARRIER)
      emit_barrier_after (insn);
  
+   /* In case we've zapped an conditional jump, we need to kill the cc0
+      setter too if available.  */
+ #ifdef HAVE_cc0
+   insn = src->end;
+   if (GET_CODE (insn) == JUMP_INSN)
+     insn = prev_nonnote_insn (insn);
+   if (sets_cc0_p (insn))
+     {
+       if (insn == src->end)
+ 	src->end = PREV_INSN (insn);
+       flow_delete_insn (insn);
+     }
+ #endif
+ 
    if (e->dest != target)
      redirect_edge_succ (e, target);
    return true;
*************** redirect_edge_and_branch (e, target)
*** 1766,1772 ****
        for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
  	if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
  	  {
! 	    RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
  	    --LABEL_NUSES (old_label);
  	    ++LABEL_NUSES (new_label);
  	  }
--- 1783,1789 ----
        for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
  	if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
  	  {
! 	    RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
  	    --LABEL_NUSES (old_label);
  	    ++LABEL_NUSES (new_label);
  	  }
*************** redirect_edge_and_branch (e, target)
*** 1815,1820 ****
--- 1832,1839 ----
        if (s)
  	{
  	  s->flags |= e->flags;
+ 	  s->probability += e->probability;
+ 	  s->count += e->count;
  	  remove_edge (e);
  	}
        else