re PR tree-optimization/81462 (ICE in estimate_bb_frequencies at gcc/predict.c:3546)

	PR middle-end/81462
	* predict.c (set_even_probabilities): Cleanup; do not affect
	probabilities that are already known.
	(combine_predictions_for_bb): Call even when count is set.

	* g++.dg/torture/pr81462.C: New testcase.

From-SVN: r250310

gcc/ChangeLog

+2017-07-18  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR middle-end/81462
+	* predict.c (set_even_probabilities): Cleanup; do not affect
+	probabilities that are already known.
+	(combine_predictions_for_bb): Call even when count is set.
+
 2017-07-18  Nathan Sidwell  <nathan@acm.org>
 
 	* tree-parloops.c (try_transform_to_exit_first_loop_alt): Use

gcc/predict.c

@@ -817,16 +817,25 @@ static void
 set_even_probabilities (basic_block bb,
 			hash_set<edge> *unlikely_edges = NULL)
 {
-  unsigned nedges = 0;
+  unsigned nedges = 0, unlikely_count = 0;
   edge e = NULL;
   edge_iterator ei;
+  profile_probability all = profile_probability::always ();
 
   FOR_EACH_EDGE (e, ei, bb->succs)
-    if (!unlikely_executed_edge_p (e))
-      nedges ++;
+    if (e->probability.initialized_p ())
+      all -= e->probability;
+    else if (!unlikely_executed_edge_p (e))
+      {
+        nedges ++;
+        if (unlikely_edges != NULL && unlikely_edges->contains (e))
+	  {
+	    all -= profile_probability::very_unlikely ();
+	    unlikely_count++;
+	  }
+      }
 
   /* Make the distribution even if all edges are unlikely.  */
-  unsigned unlikely_count = unlikely_edges ? unlikely_edges->elements () : 0;
   if (unlikely_count == nedges)
     {
       unlikely_edges = NULL;
@@ -836,13 +845,14 @@ set_even_probabilities (basic_block bb,
   unsigned c = nedges - unlikely_count;
 
   FOR_EACH_EDGE (e, ei, bb->succs)
-    if (!unlikely_executed_edge_p (e))
+    if (e->probability.initialized_p ())
+      ;
+    else if (!unlikely_executed_edge_p (e))
       {
 	if (unlikely_edges != NULL && unlikely_edges->contains (e))
 	  e->probability = profile_probability::very_unlikely ();
 	else
-	  e->probability = profile_probability::guessed_always ()
-				.apply_scale (1, c);
+	  e->probability = all.apply_scale (1, c).guessed ();
       }
     else
       e->probability = profile_probability::never ();
@@ -1151,7 +1161,7 @@ combine_predictions_for_bb (basic_block bb, bool dry_run)
 	  if (pred->ep_probability <= PROB_VERY_UNLIKELY)
 	    unlikely_edges.add (pred->ep_edge);
 
-      if (!bb->count.initialized_p () && !dry_run)
+      if (!dry_run)
 	set_even_probabilities (bb, &unlikely_edges);
       clear_bb_predictions (bb);
       if (dump_file)

gcc/testsuite/ChangeLog

+2017-07-18  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR middle-end/81462
+	* g++.dg/torture/pr81462.C: New testcase.
+
 2017-07-18  Bin Cheng  <bin.cheng@arm.com>
 
 	PR target/81408

gcc/testsuite/g++.dg/torture/pr81462.C

+// { dg-do compile }
+// { dg-options "-O1 -fno-ipa-pure-const" }
+struct B {
+        B* self;
+        B() : self( this ) { self->f(); }
+        virtual void f() = 0;
+    };
+
+    struct D : B
+    {
+        void f() {}
+    };
+
+    int main()
+    {
+        D d;
+    }