diff --git a/Optimizer/Optimizer.cs b/Optimizer/Optimizer.cs
index 7b0be66cd..f17c93672 100644
--- a/Optimizer/Optimizer.cs
+++ b/Optimizer/Optimizer.cs
@@ -704,6 +704,11 @@ namespace PascalABCCompiler
         private void IncreaseNumUseVar(local_block_variable_reference lvr)
         {
             VarInfo vi = helper.GetVariable(lvr.var);
+            if (vi == null)
+            {
+                helper.AddVariable(lvr.var);
+                vi = helper.GetVariable(lvr.var);
+            }
             if (vi == null) return;
             vi.num_use++;
             vi.act_num_use++;
diff --git a/Optimizer/OptimizerTools.cs b/Optimizer/OptimizerTools.cs
index 5aa169660..526040b1b 100644
--- a/Optimizer/OptimizerTools.cs
+++ b/Optimizer/OptimizerTools.cs
@@ -43,7 +43,8 @@ namespace PascalABCCompiler
         public void AddVariable(var_definition_node vdn)
         {
             VarInfo vi = new VarInfo();
-            ht[vdn] = vi;
+            if (ht[vdn] == null)
+                ht[vdn] = vi;
         }
 
         public VarInfo GetVariable(var_definition_node vdn)