Fix loop distribution bug with merging edges that creates too many edges.

gcc/
	* tree-loop-distribution.c (pg_add_dependence_edges): Return 2 if
	this_dir is 2.  Check for this_dir non-zero before dir != this_dir
	check.

From-SVN: r242038

gcc/ChangeLog

+2016-11-10  Jim Wilson  <jim.wilson@linaro.org>
+
+	* tree-loop-distribution.c (pg_add_dependence_edges): Return 2 if
+	this_dir is 2.  Check for this_dir non-zero before dir != this_dir
+	check.
+
 2016-11-10  Jakub Jelinek  <jakub@redhat.com>
 
 	* omp-low.c (lower_omp_target): Fix up argument to is_reference.

gcc/tree-loop-distribution.c

@@ -1408,9 +1408,11 @@ pg_add_dependence_edges (struct graph *rdg, vec<loop_p> loops, int dir,
 	else
 	  this_dir = 0;
 	free_dependence_relation (ddr);
-	if (dir == 0)
+	if (this_dir == 2)
+	  return 2;
+	else if (dir == 0)
 	  dir = this_dir;
-	else if (dir != this_dir)
+	else if (this_dir != 0 && dir != this_dir)
 	  return 2;
 	/* Shuffle "back" dr1.  */
 	dr1 = saved_dr1;