bb-reorer.c (find_rarely_executed_basic_blocks_and_crossin_edges): trust precise profiles.

	* bb-reorer.c (find_rarely_executed_basic_blocks_and_crossin_edges):
	trust precise profiles.

From-SVN: r266726

gcc/ChangeLog

+2018-12-02  Jan Hubicka  <jh@suse.cz>
+
+	* bb-reorer.c (find_rarely_executed_basic_blocks_and_crossin_edges):
+	trust precise profiles.
+
 2018-12-02  Jakub Jelinek  <jakub@redhat.com>
 
 	* tree-nested.c (convert_nonlocal_omp_clauses,

gcc/bb-reorder.c

@@ -1663,11 +1663,13 @@ find_rarely_executed_basic_blocks_and_crossing_edges (void)
 
       if (probably_never_executed_bb_p (cfun, bb))
         {
+          cold_bb = true;
+
           /* Handle profile insanities created by upstream optimizations
              by also checking the incoming edge weights. If there is a non-cold
              incoming edge, conservatively prevent this block from being split
              into the cold section.  */
-          cold_bb = true;
+	  if (!bb->count.precise_p ())
 	    FOR_EACH_EDGE (e, ei, bb->preds)
 	      if (!probably_never_executed_edge_p (cfun, e))
 		{