diff --git a/src/compiler/glsl/opt_constant_propagation.cpp b/src/compiler/glsl/opt_constant_propagation.cpp
index 05dc71efb72..f91498b45cd 100644
--- a/src/compiler/glsl/opt_constant_propagation.cpp
+++ b/src/compiler/glsl/opt_constant_propagation.cpp
@@ -77,20 +77,17 @@ public:
 };
 
 
-class kill_entry : public exec_node
+class kill_entry
 {
 public:
    /* override operator new from exec_node */
    DECLARE_LINEAR_ZALLOC_CXX_OPERATORS(kill_entry)
 
-   kill_entry(ir_variable *var, unsigned write_mask)
+   explicit kill_entry(unsigned write_mask)
    {
-      assert(var);
-      this->var = var;
       this->write_mask = write_mask;
    }
 
-   ir_variable *var;
    unsigned write_mask;
 };
 
@@ -386,7 +383,7 @@ ir_constant_propagation_visitor::handle_if_block(exec_list *instructions)
    hash_entry *htk;
    hash_table_foreach(new_kills, htk) {
       kill_entry *k = (kill_entry *) htk->data;
-      kill(k->var, k->write_mask);
+      kill((ir_variable *) htk->key, k->write_mask);
    }
 }
 
@@ -433,7 +430,7 @@ ir_constant_propagation_visitor::visit_enter(ir_loop *ir)
    hash_entry *htk;
    hash_table_foreach(new_kills, htk) {
       kill_entry *k = (kill_entry *) htk->data;
-      kill(k->var, k->write_mask);
+      kill((ir_variable *) htk->key, k->write_mask);
    }
 
    /* already descended into the children. */
@@ -469,7 +466,7 @@ ir_constant_propagation_visitor::kill(ir_variable *var, unsigned write_mask)
    }
    /* Not already in the hash table.  Make new entry. */
    _mesa_hash_table_insert(this->kills, var,
-                           new(this->lin_ctx) kill_entry(var, write_mask));
+                           new(this->lin_ctx) kill_entry(write_mask));
 }
 
 /**