predict.c (determine_unlikely_bbs): Handle correctly BBs which appears in the queue multiple times.

	* predict.c (determine_unlikely_bbs): Handle correctly BBs
	which appears in the queue multiple times.

From-SVN: r256648

gcc/ChangeLog

+2018-01-13  Jan Hubicka  <hubicka@ucw.cz>
+
+	* predict.c (determine_unlikely_bbs): Handle correctly BBs
+	which appears in the queue multiple times.
+
 2018-01-13  Richard Sandiford  <richard.sandiford@linaro.org>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>

gcc/predict.c

@@ -3565,6 +3565,8 @@ determine_unlikely_bbs ()
   while (worklist.length () > 0)
     {
       bb = worklist.pop ();
+      if (bb->count == profile_count::zero ())
+	continue;
       if (bb != ENTRY_BLOCK_PTR_FOR_FN (cfun))
 	{
 	  bool found = false;
@@ -3583,8 +3585,7 @@ determine_unlikely_bbs ()
 	  if (found)
 	    continue;
 	}
-      if (!(bb->count == profile_count::zero ())
-	  && (dump_file && (dump_flags & TDF_DETAILS)))
+      if (dump_file && (dump_flags & TDF_DETAILS))
 	fprintf (dump_file,
 		 "Basic block %i is marked unlikely by backward prop\n",
 		 bb->index);
@@ -3594,6 +3595,7 @@ determine_unlikely_bbs ()
 	  {
 	    if (!(e->src->count == profile_count::zero ()))
 	      {
+		gcc_checking_assert (nsuccs[e->src->index] > 0);
 	        nsuccs[e->src->index]--;
 	        if (!nsuccs[e->src->index])
 		  worklist.safe_push (e->src);