Index: gcc/tree-ssa-loop-ivopts.c
===================================================================
--- gcc/tree-ssa-loop-ivopts.c	(revision 173380)
+++ gcc/tree-ssa-loop-ivopts.c	(working copy)
@@ -4688,6 +4688,8 @@ determine_iv_cost (struct ivopts_data *d
 
   base = cand->iv->base;
   cost_base = force_var_cost (data, base, NULL);
+  if (cost_base.cost == 0)
+      cost_base.cost = COSTS_N_INSNS (1);
   cost_step = add_cost (TYPE_MODE (TREE_TYPE (base)), data->speed);
 
   cost = cost_step + adjust_setup_cost (data, cost_base.cost);