[PATCH] Guard against applying scale with 0 denominator

[Eugene Rozenfeld via Gcc-patches]

Calling count.apply_scale with a 0 denominator causes an assert.
This change guards against that.

Tested on x86_64-pc-linux-gnu.

gcc/ChangeLog:
        * tree-loop-vect-manip.cc (vect_do_peeling): Guard against applying 
scale with 0 denominator.
---
 gcc/tree-vect-loop-manip.cc | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index 1d4337eb261..db54ae69e45 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -2989,10 +2989,11 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, 
tree nitersm1,
             get lost if we scale down to 0.  */
          basic_block *bbs = get_loop_body (epilog);
          for (unsigned int i = 0; i < epilog->num_nodes; i++)
-           bbs[i]->count = bbs[i]->count.apply_scale
-                                (bbs[i]->count,
-                                 bbs[i]->count.apply_probability
-                                   (prob_vector));
+           if (bbs[i]->count.nonzero_p ())
+             bbs[i]->count = bbs[i]->count.apply_scale
+                                  (bbs[i]->count,
+                                   bbs[i]->count.apply_probability
+                                     (prob_vector));
          free (bbs);
        }

--
2.25.1