basic-block.h (update_bb_profile_after_threading): Declare.

	* basic-block.h (update_bb_profile_after_threading): Declare.
	* cfg.c (update_bb_profile_after_threading): Break out from ...
	* cfgcleanup.c (try_forward_edges): ... here; use it.
	* tree-ssa-dom.c (thread_across_edge): Use it.
	* tree-ssa-threadupdate.c (create_block_for_threading): Zero out
	profile of the new BB.

From-SVN: r87730

6 files changed, 89 insertions, 26 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4863acc..6bc408a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2004-09-19  Jan Hubicka  <jh@suse.cz>
+
+	* basic-block.h (update_bb_profile_after_threading): Declare.
+	* cfg.c (update_bb_profile_after_threading): Break out from ...
+	* cfgcleanup.c (try_forward_edges): ... here; use it.
+	* tree-ssa-dom.c (thread_across_edge): Use it.
+	* tree-ssa-threadupdate.c (create_block_for_threading): Zero out
+	profile of the new BB.
+
 2004-09-19  Daniel Berlin  <dberlin@dberlin.org>
 
 	* tree-ssa-pre.c (insert_into_set): Don't put
diff --git a/gcc/basic-block.h b/gcc/basic-block.h
index 037f0ac..21fd7bb 100644
--- a/gcc/basic-block.h
+++ b/gcc/basic-block.h
@@ -746,6 +746,7 @@ extern basic_block next_dom_son (enum cdi_direction, basic_block);
 extern edge try_redirect_by_replacing_jump (edge, basic_block, bool);
 extern void break_superblocks (void);
 extern void check_bb_profile (basic_block, FILE *);
+extern void update_bb_profile_for_threading (basic_block, int, gcov_type, edge);
 
 #include "cfghooks.h"
 
diff --git a/gcc/cfg.c b/gcc/cfg.c
index 3c2ef48..b5d28c3 100644
--- a/gcc/cfg.c
+++ b/gcc/cfg.c
@@ -888,3 +888,64 @@ brief_dump_cfg (FILE *file)
       dump_cfg_bb_info (file, bb);
     }
 }
+
+/* An edge originally destinating BB of FREQUENCY and COUNT has been proved to
+   leave the block by TAKEN_EDGE.  Update profile of BB such that edge E can be
+   redirected to destiantion of TAKEN_EDGE. 
+
+   This function may leave the profile inconsistent in the case TAKEN_EDGE
+   frequency or count is believed to be lower than FREQUENCY or COUNT
+   respectivly.  */
+void
+update_bb_profile_for_threading (basic_block bb, int edge_frequency,
+				 gcov_type count, edge taken_edge)
+{
+  edge c;
+  int prob;
+
+  bb->count -= count;
+  if (bb->count < 0)
+    bb->count = 0;
+
+  /* Compute the probability of TAKEN_EDGE being reached via threaded edge.
+     Watch for overflows.  */
+  if (bb->frequency)
+    prob = edge_frequency * REG_BR_PROB_BASE / bb->frequency;
+  else
+    prob = 0;
+  if (prob > taken_edge->probability)
+    {
+      if (dump_file)
+	fprintf (dump_file, "Jump threading proved probability of edge "
+		 "%i->%i too small (it is %i, should be %i).\n",
+		 taken_edge->src->index, taken_edge->dest->index,
+		 taken_edge->probability, prob);
+      prob = taken_edge->probability;
+    }
+
+  /* Now rescale the probabilities.  */
+  taken_edge->probability -= prob;
+  prob = REG_BR_PROB_BASE - prob;
+  bb->frequency -= edge_frequency;
+  if (bb->frequency < 0)
+    bb->frequency = 0;
+  if (prob <= 0)
+    {
+      if (dump_file)
+	fprintf (dump_file, "Edge frequencies of bb %i has been reset, "
+		 "frequency of block should end up being 0, it is %i\n",
+		 bb->index, bb->frequency);
+      bb->succ->probability = REG_BR_PROB_BASE;
+      for (c = bb->succ->succ_next; c; c = c->succ_next)
+	c->probability = 0;
+    }
+  else
+    for (c = bb->succ; c; c = c->succ_next)
+      c->probability = ((c->probability * REG_BR_PROB_BASE) / (double) prob);
+
+  if (bb != taken_edge->src)
+    abort ();
+  taken_edge->count -= count;
+  if (taken_edge->count < 0)
+    taken_edge->count = 0;
+}
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index 08714f6..f9d0607 100644
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -614,41 +614,23 @@ try_forward_edges (int mode, basic_block b)
 	    {
 	      edge t;
 
-	      first->count -= edge_count;
-	      if (first->count < 0)
-		first->count = 0;
-	      first->frequency -= edge_frequency;
-	      if (first->frequency < 0)
-		first->frequency = 0;
 	      if (first->succ->succ_next)
 		{
-		  edge e;
-		  int prob;
-		  
 		  gcc_assert (n < nthreaded_edges);
 		  t = threaded_edges [n++];
 		  gcc_assert (t->src == first);
-		  if (first->frequency)
-		    prob = edge_frequency * REG_BR_PROB_BASE / first->frequency;
-		  else
-		    prob = 0;
-		  if (prob > t->probability)
-		    prob = t->probability;
-		  t->probability -= prob;
-		  prob = REG_BR_PROB_BASE - prob;
-		  if (prob <= 0)
-		    {
-		      first->succ->probability = REG_BR_PROB_BASE;
-		      first->succ->succ_next->probability = 0;
-		    }
-		  else
-		    for (e = first->succ; e; e = e->succ_next)
-		      e->probability = ((e->probability * REG_BR_PROB_BASE)
-					/ (double) prob);
+		  update_bb_profile_for_threading (first, edge_frequency,
+						   edge_count, t);
 		  update_br_prob_note (first);
 		}
 	      else
 		{
+		  first->count -= edge_count;
+		  if (first->count < 0)
+		    first->count = 0;
+		  first->frequency -= edge_frequency;
+		  if (first->frequency < 0)
+		    first->frequency = 0;
 		  /* It is possible that as the result of
 		     threading we've removed edge as it is
 		     threaded to the fallthru edge.  Avoid
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index b99f189..f285011 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -697,6 +697,8 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
 	     bypass the conditional at our original destination.   */
 	  if (dest)
 	    {
+	      update_bb_profile_for_threading (e->dest, EDGE_FREQUENCY (e),
+					       e->count, taken_edge);
 	      e->aux = taken_edge;
 	      bb_ann (e->dest)->incoming_edge_threaded = true;
 	    }
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c
index ce6dcad..112509f 100644
--- a/gcc/tree-ssa-threadupdate.c
+++ b/gcc/tree-ssa-threadupdate.c
@@ -172,17 +172,25 @@ static void
 create_block_for_threading (basic_block bb, struct redirection_data *rd)
 {
   tree phi;
+  edge e;
 
   /* We can use the generic block duplication code and simply remove
      the stuff we do not need.  */
   rd->dup_block = duplicate_block (bb, NULL);
 
+  /* Zero out the profile, since the block is unreachable for now.  */
+  rd->dup_block->frequency = 0;
+  rd->dup_block->count = 0;
+
   /* The call to duplicate_block will copy everything, including the
      useless COND_EXPR or SWITCH_EXPR at the end of the block.  We just remove
      the useless COND_EXPR or SWITCH_EXPR here rather than having a
      specialized block copier.  */
   remove_last_stmt_and_useless_edges (rd->dup_block, rd->outgoing_edge->dest);
 
+  for (e = rd->dup_block->succ; e; e = e->succ_next)
+    e->count = 0;
+
   /* If there are any PHI nodes at the destination of the outgoing edge
      from the duplicate block, then we will need to add a new argument
      to them.  The argument should have the same value as the argument