Cleanup profile updating code in unrolling and splitting

I have noticed that for all these three cases I need same update of
loop exit probability.  While my earlier patch unified it for unrollers,
this patch makes it more general and also simplifies
tree-ssa-loop-split.cc.

I also refactored the code, since with all the special cases for
corrupted profile it gets relatively long.
I now also handle multiple loop exits in RTL unroller.

Bootstrapped/regtested x86_64-linux, comitted.
gcc/ChangeLog:

	* cfgloopmanip.cc (loop_count_in): Break out from ...
	(loop_exit_for_scaling): Break out from ...
	(update_loop_exit_probability_scale_dom_bbs): Break out from ...;
	add more sanity check and debug info.
	(scale_loop_profile): ... here.
	(create_empty_loop_on_edge): Fix whitespac.
	* cfgloopmanip.h (update_loop_exit_probability_scale_dom_bbs): Declare.
	* loop-unroll.cc (unroll_loop_constant_iterations): Use
	update_loop_exit_probability_scale_dom_bbs.
	* tree-ssa-loop-manip.cc (update_exit_probability_after_unrolling): Remove.
	(tree_transform_and_unroll_loop): Use
	update_loop_exit_probability_scale_dom_bbs.
	* tree-ssa-loop-split.cc (split_loop): Use
	update_loop_exit_probability_scale_dom_bbs.

1 files changed, 6 insertions, 24 deletions

diff --git a/gcc/tree-ssa-loop-manip.cc b/gcc/tree-ssa-loop-manip.cc
index e58892e..e743691 100644
--- a/gcc/tree-ssa-loop-manip.cc
+++ b/gcc/tree-ssa-loop-manip.cc
@@ -1040,29 +1040,6 @@ determine_exit_conditions (class loop *loop, class tree_niter_desc *desc,
   *exit_bound = bound;
 }
 
-/* Updat NEW_EXIT probability after loop has been unrolled.  */
-
-void
-update_exit_probability_after_unrolling (class loop *loop, edge new_exit)
-{
-  /* gimple_duplicate_loop_body_to_header_edge depending on
-     DLTHE_FLAG_UPDATE_FREQ either keeps original frequency of the loop header
-     or scales it down accordingly.
-     However exit edge probability is kept as original.  Fix it if needed
-     and compensate.  */
-  profile_probability new_prob
-	  = loop_preheader_edge
-		  (loop)->count ().probability_in (new_exit->src->count);
-  if (!(new_prob == new_exit->probability))
-    {
-      profile_count old_count = new_exit->src->count - new_exit->count ();
-      set_edge_probability_and_rescale_others (new_exit, new_prob);
-      profile_count new_count = new_exit->src->count - new_exit->count ();
-      scale_dominated_blocks_in_loop (loop, new_exit->src,
-				      new_count, old_count);
-    }
-}
-
 /* Unroll LOOP FACTOR times.  LOOP is known to have a single exit edge
    whose source block dominates the latch.  DESC describes the number of
    iterations of LOOP.
@@ -1289,7 +1266,12 @@ tree_transform_and_unroll_loop (class loop *loop, unsigned factor,
   update_ssa (TODO_update_ssa);
 
   new_exit = single_dom_exit (loop);
-  update_exit_probability_after_unrolling (loop, new_exit);
+  /* gimple_duplicate_loop_body_to_header_edge depending on
+     DLTHE_FLAG_UPDATE_FREQ either keeps original frequency of the loop header
+     or scales it down accordingly.
+     However exit edge probability is kept as original.  Fix it if needed
+     and compensate.  */
+  update_loop_exit_probability_scale_dom_bbs (loop, new_exit);
   if (!single_loop_p)
     {
       /* Finally create the new counter for number of iterations and add