fix up hot/cold partitioning on ports that don't have long conditional branches

[Mike Stump <mikestump@comcast.net>]

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This patch fixes up hot/cold partitioning on ports that don't have long conditional branches.  I'll note that the entire file has lots of other jump optimizations that are suspect.

Ok?


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2011-04-21  Mike Stump  <mikestump@comcast.net>

	* reorg.c (relax_delay_slots): Don't delete a jump that crosses a
	section boundary.
	(follow_jumps): Don't replace a short conditional jump with a
	long conditional jump when the port doesn't have long
	conditional jumps.
	(fill_slots_from_thread): Pass insn to follow_jumps.
	(relax_delay_slots): Likewise.

Index: reorg.c
===================================================================
--- reorg.c	(revision 1301)
+++ reorg.c	(working copy)
@@ -2509,7 +2509,7 @@
    since that tells caller to avoid changing the insn.  */
 
 static rtx
-follow_jumps (rtx label)
+follow_jumps (rtx label, rtx jump)
 {
   rtx insn;
   rtx next;
@@ -2529,6 +2529,16 @@
     {
       rtx tem;
 
+      /* If a label crosses a section boundary and we're thinking
+	 about changing a conditional jump to be a conditional jump
+	 across that boundary, don't do it if the port doesn't have
+	 long conditional branches.  We can however jump to the label
+	 just before we cross such a boundary.  */
+      if (!HAS_LONG_COND_BRANCH
+	  && find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
+	  && (condjump_p (jump) || condjump_in_parallel_p (jump)))
+	return value;
+
       /* If we have found a cycle, make the insn jump to itself.  */
       if (JUMP_LABEL (insn) == label)
 	return label;
@@ -2991,7 +3001,7 @@
 	  && redirect_with_delay_list_safe_p (insn,
 					      JUMP_LABEL (new_thread),
 					      delay_list))
-	new_thread = follow_jumps (JUMP_LABEL (new_thread));
+	new_thread = follow_jumps (JUMP_LABEL (new_thread), new_thread);
 
       if (new_thread == 0)
 	label = find_end_label ();
@@ -3342,12 +3352,13 @@
 	  && (condjump_p (insn) || condjump_in_parallel_p (insn))
 	  && (target_label = JUMP_LABEL (insn)) != 0)
 	{
-	  target_label = skip_consecutive_labels (follow_jumps (target_label));
+	  target_label = skip_consecutive_labels (follow_jumps (target_label, insn));
 	  if (target_label == 0)
 	    target_label = find_end_label ();
 
 	  if (target_label && next_active_insn (target_label) == next
-	      && ! condjump_in_parallel_p (insn))
+	      && ! condjump_in_parallel_p (insn)
+	      && find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX) == NULL_RTX)
 	    {
 	      delete_jump (insn);
 	      continue;
@@ -3492,7 +3503,7 @@
 	{
 	  /* If this jump goes to another unconditional jump, thread it, but
 	     don't convert a jump into a RETURN here.  */
-	  trial = skip_consecutive_labels (follow_jumps (target_label));
+	  trial = skip_consecutive_labels (follow_jumps (target_label, delay_insn));
 	  if (trial == 0)
 	    trial = find_end_label ();