Fix off by one error in loop-unroll.c (PR rtl-optimization/82675).

2017-12-19  Martin Liska  <mliska@suse.cz>

	PR rtl-optimization/82675
	* loop-unroll.c (unroll_loop_constant_iterations): Allocate one
	more element in sbitmap.

From-SVN: r255818

gcc/ChangeLog

+2017-12-19  Martin Liska  <mliska@suse.cz>
+
+	PR rtl-optimization/82675
+	* loop-unroll.c (unroll_loop_constant_iterations): Allocate one
+	more element in sbitmap.
+
 2017-12-19  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* gimplify.c (gimplify_expr): Use error_operand_p.

gcc/loop-unroll.c

@@ -498,7 +498,7 @@ unroll_loop_constant_iterations (struct loop *loop)
 
   exit_mod = niter % (max_unroll + 1);
 
-  auto_sbitmap wont_exit (max_unroll + 1);
+  auto_sbitmap wont_exit (max_unroll + 2);
   bitmap_ones (wont_exit);
 
   auto_vec<edge> remove_edges;