rtlanal.c (label_is_jump_target_p): Return true for a matching REG_LABEL_TARGET.

	* rtlanal.c (label_is_jump_target_p): Return true for a matching
	REG_LABEL_TARGET.
	* reorg.c (fill_slots_from_thread): Correct last change to use
	NULL_RTX, not NULL.  Outside of REG_NOTES loop, increase and
	decrease LABEL_NUSES for JUMP_LABEL (trial), not XEXP (note, 0).
	* jump.c (mark_jump_label_1): Add comment for last change
	regarding JUMP_LABEL setting.
	* gcse.c (add_label_notes): Remove conditional that the label is
	mentioned in insn before adding regnote.
	* sched-rgn.c (is_cfg_nonregular): Don't return 1 for a
	single_set insn only feeding a label to a jump through a
	register that dies there.

From-SVN: r130398

gcc/ChangeLog

+2007-11-24  Hans-Peter Nilsson  <hp@axis.com>
+
+	* rtlanal.c (label_is_jump_target_p): Return true for a matching
+	REG_LABEL_TARGET.
+	* reorg.c (fill_slots_from_thread): Correct last change to use
+	NULL_RTX, not NULL.  Outside of REG_NOTES loop, increase and
+	decrease LABEL_NUSES for JUMP_LABEL (trial), not XEXP (note, 0).
+	* jump.c (mark_jump_label_1): Add comment for last change
+	regarding JUMP_LABEL setting.
+	* gcse.c (add_label_notes): Remove conditional that the label is
+	mentioned in insn before adding regnote.
+	* sched-rgn.c (is_cfg_nonregular): Don't return 1 for a
+	single_set insn only feeding a label to a jump through a
+	register that dies there.
+
 2007-11-23  Dirk Mueller  <dmueller@suse.de>
 	Richard Guenther <rguenther@suse.de>
 

gcc/gcse.c

@@ -4614,18 +4614,16 @@ add_label_notes (rtx x, rtx insn)
 	 We no longer ignore such label references (see LABEL_REF handling in
 	 mark_jump_label for additional information).  */
 
-	if (reg_mentioned_p (XEXP (x, 0), insn))
-	  {
-	    /* There's no reason for current users to emit jump-insns
-	       with such a LABEL_REF, so we don't have to handle
-	       REG_LABEL_TARGET notes.  */
+      /* There's no reason for current users to emit jump-insns with
+	 such a LABEL_REF, so we don't have to handle REG_LABEL_TARGET
+	 notes.  */
       gcc_assert (!JUMP_P (insn));
       REG_NOTES (insn)
 	= gen_rtx_INSN_LIST (REG_LABEL_OPERAND, XEXP (x, 0),
 			     REG_NOTES (insn));
       if (LABEL_P (XEXP (x, 0)))
 	LABEL_NUSES (XEXP (x, 0))++;
-	  }
+
       return;
     }
 

gcc/jump.c

@@ -1051,6 +1051,9 @@ mark_jump_label_1 (rtx x, rtx insn, bool in_mem, bool is_target)
 	if (insn)
 	  {
 	    if (is_target
+		/* Do not change a previous setting of JUMP_LABEL.  If the
+		   JUMP_LABEL slot is occupied by a different label,
+		   create a note for this label.  */
 		&& (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == label))
 	      JUMP_LABEL (insn) = label;
 	    else

gcc/reorg.c

@@ -2740,7 +2740,7 @@ fill_slots_from_thread (rtx insn, rtx condition, rtx thread,
 			 temporarily increment the use count on any referenced
 			 label lest it be deleted by delete_related_insns.  */
 		      for (note = REG_NOTES (trial);
-			   note != NULL;
+			   note != NULL_RTX;
 			   note = XEXP (note, 1))
 			if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND
 			    || REG_NOTE_KIND (note) == REG_LABEL_TARGET)
@@ -2754,12 +2754,12 @@ fill_slots_from_thread (rtx insn, rtx condition, rtx thread,
 					  == REG_LABEL_OPERAND);
 			  }
 		      if (JUMP_P (trial) && JUMP_LABEL (trial))
-			LABEL_NUSES (XEXP (note, 0))++;
+			LABEL_NUSES (JUMP_LABEL (trial))++;
 
 		      delete_related_insns (trial);
 
 		      for (note = REG_NOTES (trial);
-			   note != NULL;
+			   note != NULL_RTX;
 			   note = XEXP (note, 1))
 			if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND
 			    || REG_NOTE_KIND (note) == REG_LABEL_TARGET)
@@ -2773,7 +2773,7 @@ fill_slots_from_thread (rtx insn, rtx condition, rtx thread,
 					  == REG_LABEL_OPERAND);
 			  }
 		      if (JUMP_P (trial) && JUMP_LABEL (trial))
-			LABEL_NUSES (XEXP (note, 0))--;
+			LABEL_NUSES (JUMP_LABEL (trial))--;
 		    }
 		  else
 		    new_thread = next_active_insn (trial);

gcc/rtlanal.c

@@ -3434,6 +3434,9 @@ label_is_jump_target_p (const_rtx label, const_rtx jump_insn)
 	  return true;
     }
 
+  if (find_reg_note (jump_insn, REG_LABEL_TARGET, label))
+    return true;
+
   return false;
 }
 

gcc/sched-rgn.c

@@ -320,16 +320,40 @@ is_cfg_nonregular (void)
   FOR_EACH_BB (b)
     FOR_BB_INSNS (b, insn)
       {
-	/* Check for labels referred to but (at least not directly) as
-	   jump targets.  */
-	if (INSN_P (insn)
-	    && find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX))
-	  return 1;
+	rtx note, next, set, dest;
 
 	/* If this function has a computed jump, then we consider the cfg
 	   not well structured.  */
 	if (JUMP_P (insn) && computed_jump_p (insn))
 	  return 1;
+
+	if (!INSN_P (insn))
+	  continue;
+
+	note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX);
+	if (note == NULL_RTX)
+	  continue;
+
+	/* For that label not to be seen as a referred-to label, this
+	   must be a single-set which is feeding a jump *only*.  This
+	   could be a conditional jump with the label split off for
+	   machine-specific reasons or a casesi/tablejump.  */
+	next = next_nonnote_insn (insn);
+	if (next == NULL_RTX
+	    || !JUMP_P (next)
+	    || (JUMP_LABEL (next) != XEXP (note, 0)
+		&& find_reg_note (next, REG_LABEL_TARGET,
+				  XEXP (note, 0)) == NULL_RTX)
+	    || BLOCK_FOR_INSN (insn) != BLOCK_FOR_INSN (next))
+	  return 1;
+
+	set = single_set (insn);
+	if (set == NULL_RTX)
+	  return 1;
+
+	dest = SET_DEST (set);
+	if (!REG_P (dest) || !dead_or_set_p (next, dest))
+	  return 1;
       }
 
   /* Unreachable loops with more than one basic block are detected