flow.c (redirect_edge_and_branch): Bail out on complex edges.

	* flow.c (redirect_edge_and_branch): Bail out on complex edges.
	(try_optimize_cfg): Do not remove tail recursive labels before sibcall.
	* jump.c (mark_jump_label): Do not forward branches.

Co-Authored-By: Jan Hubicka <jh@suse.cz>

From-SVN: r44118

gcc/ChangeLog

+Wed Jul 18 18:46:30 CEST 2001  Richard Henderson <rth@cygnus.com>
+			       Jan Hubicka  <jh@suse.cz>
+
+	* flow.c (redirect_edge_and_branch): Bail out on complex edges.
+	(try_optimize_cfg): Do not remove tail recursive labels before sibcall.
+	* jump.c (mark_jump_label): Do not forward branches.
+
 Wed Jul 18 18:35:01 CEST 2001  Jan Hubicka  <jh@suse.cz>
 
 	* cse.c (delete_trivially_dead_insns): Delete the libcall block

gcc/flow.c

@@ -1777,6 +1777,9 @@ redirect_edge_and_branch (e, target)
   basic_block src = e->src;
   rtx insn = src->end;
 
+  if (e->flags & EDGE_COMPLEX)
+    return false;
+
   if (try_redirect_by_replacing_jump (e, target))
     return true;
   /* Do this fast path late, as we want above code to simplify for cases
@@ -3683,30 +3686,15 @@ try_optimize_cfg (mode)
 	      changed = 1;
 	      b = c;
 	    }
-	  /* The fallthru forwarder block can be deleted.  */
-	  if (b->pred->pred_next == NULL
-	      && forwarder_block_p (b)
-	      && n_basic_blocks > 1
-	      && (b->pred->flags & EDGE_FALLTHRU)
-	      && (b->succ->flags & EDGE_FALLTHRU))
-	    {
-	      if (rtl_dump_file)
-		fprintf (rtl_dump_file, "Deleting fallthru block %i.\n",
-			 b->index);
-	      c = BASIC_BLOCK (i ? i - 1 : i + 1);
-	      redirect_edge_succ (b->pred, b->succ->dest);
-	      flow_delete_block (b);
-	      changed = 1;
-	      b = c;
-	    }
-
 	  /* Remove code labels no longer used.  
 	     Don't do the optimization before sibling calls are discovered,
 	     as some branches may be hidden inside CALL_PLACEHOLDERs.  */
-	  if (!(mode & CLEANUP_PRE_SIBCALL)
-	      && b->pred->pred_next == NULL
+	  if (b->pred->pred_next == NULL
 	      && (b->pred->flags & EDGE_FALLTHRU)
+	      && !(b->pred->flags & EDGE_COMPLEX)
 	      && GET_CODE (b->head) == CODE_LABEL
+	      && (!(mode & CLEANUP_PRE_SIBCALL)
+ 		  || !tail_recursion_label_p (b->head))
 	      /* If previous block does end with condjump jumping to next BB,
 	         we can't delete the label.  */
 	      && (b->pred->src == ENTRY_BLOCK_PTR
@@ -3719,12 +3707,31 @@ try_optimize_cfg (mode)
 		fprintf (rtl_dump_file, "Deleted label in block %i.\n",
 			 b->index);
 	    }
+	  /* The fallthru forwarder block can be deleted.  */
+	  if (b->pred->pred_next == NULL
+	      && forwarder_block_p (b)
+	      && n_basic_blocks > 1
+	      && (b->pred->flags & EDGE_FALLTHRU)
+	      && (b->succ->flags & EDGE_FALLTHRU)
+	      && GET_CODE (b->head) != CODE_LABEL)
+	    {
+	      if (rtl_dump_file)
+		fprintf (rtl_dump_file, "Deleting fallthru block %i.\n",
+			 b->index);
+	      c = BASIC_BLOCK (i ? i - 1 : i + 1);
+	      redirect_edge_succ (b->pred, b->succ->dest);
+	      flow_delete_block (b);
+	      changed = 1;
+	      b = c;
+	    }
+
 
 	  /* A loop because chains of blocks might be combineable.  */
 	  while ((s = b->succ) != NULL
 		 && s->succ_next == NULL
 		 && (s->flags & EDGE_EH) == 0
 		 && (c = s->dest) != EXIT_BLOCK_PTR
+	         && !(s->flags & EDGE_COMPLEX)
 		 && c->pred->pred_next == NULL
 		 /* If the jump insn has side effects,
 		    we can't kill the edge.  */

gcc/jump.c

@@ -1999,8 +1999,6 @@ mark_jump_label (x, insn, in_mem)
     case LABEL_REF:
       {
 	rtx label = XEXP (x, 0);
-	rtx olabel = label;
-	rtx next;
 
 	/* Ignore remaining references to unreachable labels that
 	   have been deleted.  */
@@ -2015,23 +2013,6 @@ mark_jump_label (x, insn, in_mem)
 	if (LABEL_REF_NONLOCAL_P (x))
 	  break;
 
-	/* If there are other labels following this one,
-	   replace it with the last of the consecutive labels.  */
-	for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
-	  {
-	    if (GET_CODE (next) == CODE_LABEL)
-	      label = next;
-	    else if (GET_CODE (next) != NOTE)
-	      break;
-	    else if ((NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
-		      || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
-		      /* ??? Optional.  Disables some optimizations, but
-			 makes gcov output more accurate with -O.  */
-		      || (flag_test_coverage
-			  && NOTE_LINE_NUMBER (next) > 0)))
-	      break;
-	  }
-
 	XEXP (x, 0) = label;
 	if (! insn || ! INSN_DELETED_P (insn))
 	  ++LABEL_NUSES (label);
@@ -2042,27 +2023,6 @@ mark_jump_label (x, insn, in_mem)
 	      JUMP_LABEL (insn) = label;
 	    else
 	      {
-		/* If we've changed the label, update notes accordingly.  */
-		if (label != olabel)
-		  {
-		    rtx note;
-
-		    /* We may have a REG_LABEL note to indicate that this
-		       instruction uses the label.  */
-		    note = find_reg_note (insn, REG_LABEL, olabel);
-		    if (note)
-		      XEXP (note, 0) = label;
-
-		    /* We may also have a REG_EQUAL note to indicate that
-		       a register is being set to the address of the
-		       label.  */
-		    note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
-		    if (note 
-			&& GET_CODE (XEXP (note, 0)) == LABEL_REF
-			&& XEXP (XEXP (note, 0), 0) == olabel)
-		      XEXP (XEXP (note, 0), 0) = label;
-		  }
-
 		/* Add a REG_LABEL note for LABEL unless there already
 		   is one.  All uses of a label, except for labels
 		   that are the targets of jumps, must have a