[PATCH] Fix PR69013

[Richard Biener]

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2016-01-13  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/69013
        * tree-ssa-uninit.c (prune_uninit_phi_opnds_in_unrealizable_paths):
        Exchange assert for a test.

Index: gcc/tree-ssa-uninit.c
===================================================================
--- gcc/tree-ssa-uninit.c       (revision 232315)
+++ gcc/tree-ssa-uninit.c       (working copy)
@@ -1093,19 +1093,21 @@ prune_uninit_phi_opnds_in_unrealizable_p
              edge opnd_edge;
              unsigned uninit_opnds2
                  = compute_uninit_opnds_pos (opnd_def_phi);
-             pred_chain_union def_preds = vNULL;
-             bool ok;
-             gcc_assert (!MASK_EMPTY (uninit_opnds2));
-             opnd_edge = gimple_phi_arg_edge (phi, i);
-             ok = is_use_properly_guarded (phi,
-                                           opnd_edge->src,
-                                           opnd_def_phi,
-                                           uninit_opnds2,
-                                           &def_preds,
-                                           visited_phis);
-             destroy_predicate_vecs (&def_preds);
-             if (!ok)
-               return false;
+             if (!MASK_EMPTY (uninit_opnds2))
+               {
+                 pred_chain_union def_preds = vNULL;
+                 bool ok;
+                 opnd_edge = gimple_phi_arg_edge (phi, i);
+                 ok = is_use_properly_guarded (phi,
+                                               opnd_edge->src,
+                                               opnd_def_phi,
+                                               uninit_opnds2,
+                                               &def_preds,
+                                               visited_phis);
+                 destroy_predicate_vecs (&def_preds);
+                 if (!ok)
+                   return false;
+               }
            }
          else
            return false;