tree-ssa-loop-ch.c (copy_loop_headers): Decrement nb_iterations_upper_bound by one.

2013-11-21  Richard Biener  <rguenther@suse.de>

	* tree-ssa-loop-ch.c (copy_loop_headers): Decrement
	nb_iterations_upper_bound by one.

From-SVN: r205198

1 files changed, 10 insertions, 0 deletions

diff --git a/gcc/tree-ssa-loop-ch.c b/gcc/tree-ssa-loop-ch.c
index df45c286790..ccaa9c8987e 100644
--- a/gcc/tree-ssa-loop-ch.c
+++ b/gcc/tree-ssa-loop-ch.c
@@ -243,6 +243,16 @@ copy_loop_headers (void)
 	 are not now, since there was the loop exit condition.  */
       split_edge (loop_preheader_edge (loop));
       split_edge (loop_latch_edge (loop));
+
+      /* We peeled off one iteration of the loop thus we can lower
+	 the maximum number of iterations if we have a previously
+	 recorded value for that.  */
+      double_int max;
+      if (get_max_loop_iterations (loop, &max))
+	{
+	  max -= double_int_one;
+	  loop->nb_iterations_upper_bound = max;
+	}
     }
 
   update_ssa (TODO_update_ssa);