diff --git a/filter/config.Y b/filter/config.Y
index 1ef5a3a8..7c077b65 100644
--- a/filter/config.Y
+++ b/filter/config.Y
@@ -317,6 +317,26 @@ f_generate_lc(struct f_inst *t1, struct f_inst *t2, struct f_inst *t3)
   return rv;
 }
 
+static inline struct f_inst *
+f_generate_path_mask(struct f_path_mask *t)
+{
+  for (struct f_path_mask *tt = t; tt; tt = tt->next) {
+    if (tt->kind == PM_ASN_EXPR) {
+      struct f_inst *mrv = f_new_inst(FI_PATHMASK_CONSTRUCT);
+      mrv->a1.p = t;
+      return mrv;
+    }
+  }
+
+  NEW_F_VAL;
+  val->type = T_PATH_MASK;
+  val->val.path_mask = t;
+
+  struct f_inst *rv = f_new_inst(FI_CONSTANT_INDIRECT);
+  rv->a1.p = val;
+
+  return rv;
+}
 
 
 CF_DECLS
@@ -708,13 +728,13 @@ constant:
  | '[' set_items ']' { DBG( "We've got a set here..." ); $$ = f_new_inst(FI_CONSTANT); $$->aux = T_SET; $$->a2.p = build_tree($2); DBG( "ook\n" ); }
  | '[' fprefix_set ']' { $$ = f_new_inst(FI_CONSTANT); $$->aux = T_PREFIX_SET;  $$->a2.p = $2; }
  | ENUM	  { $$ = f_new_inst(FI_CONSTANT); $$->aux = $1 >> 16; $$->a2.i = $1 & 0xffff; }
- | bgp_path { NEW_F_VAL; $$ = f_new_inst(FI_CONSTANT_INDIRECT); val->type = T_PATH_MASK; val->val.path_mask = $1; $$->a1.p = val; }
  ;
 
 constructor:
    '(' term ',' term ')' { $$ = f_generate_dpair($2, $4); }
  | '(' ec_kind ',' term ',' term ')' { $$ = f_generate_ec($2, $4, $6); }
  | '(' term ',' term ',' term ')' { $$ = f_generate_lc($2, $4, $6); }
+ | bgp_path { $$ = f_generate_path_mask($1); }
  ;
 
 
diff --git a/filter/filter.c b/filter/filter.c
index 023f7e2f..8b66b57e 100644
--- a/filter/filter.c
+++ b/filter/filter.c
@@ -82,8 +82,7 @@ pm_format(struct f_path_mask *p, buffer *buf)
       break;
 
     case PM_ASN_EXPR:
-      buffer_print(buf, "%u ", f_eval_asn((struct f_inst *) p->val));
-      break;
+      ASSERT(0);
     }
 
     p = p->next;
@@ -772,6 +771,32 @@ interpret(struct f_inst *what)
       break;
     }
 
+  case FI_PATHMASK_CONSTRUCT:
+    {
+      struct f_path_mask *tt = what->a1.p, *vbegin, **vv = &vbegin;
+
+      while (tt) {
+	*vv = lp_alloc(f_pool, sizeof(struct f_path_mask));
+	if (tt->kind == PM_ASN_EXPR) {
+	  struct f_val res = interpret((struct f_inst *) tt->val);
+	  (*vv)->kind = PM_ASN;
+	  if (res.type != T_INT) {
+	    runtime( "Error resolving path mask template: value not an integer" );
+	    return (struct f_val) { .type = T_VOID };
+	  }
+
+	  (*vv)->val = res.val.i;
+	} else {
+	  **vv = *tt;
+	}
+	tt = tt->next;
+	vv = &((*vv)->next);
+      }
+
+      res = (struct f_val) { .type = T_PATH_MASK, .val.path_mask = vbegin };
+      break;
+    }
+
 /* Relational operators */
 
 #define COMPARE(x) \
@@ -1550,6 +1575,8 @@ i_same(struct f_inst *f1, struct f_inst *f2)
   case FI_LT:
   case FI_LTE: TWOARGS; break;
 
+  case FI_PATHMASK_CONSTRUCT: if (!pm_same(f1->a1.p, f2->a1.p)) return 0; break;
+
   case FI_NOT: ONEARG; break;
   case FI_NOT_MATCH:
   case FI_MATCH: TWOARGS; break;
@@ -1771,14 +1798,6 @@ f_eval_int(struct f_inst *expr)
   return res.val.i;
 }
 
-u32
-f_eval_asn(struct f_inst *expr)
-{
-  /* Called as a part of another interpret call, therefore no log_reset() */
-  struct f_val res = interpret(expr);
-  return (res.type == T_INT) ? res.val.i : 0;
-}
-
 /**
  * filter_same - compare two filters
  * @new: first filter to be compared
diff --git a/filter/filter.h b/filter/filter.h
index 1d0f389e..572459d8 100644
--- a/filter/filter.h
+++ b/filter/filter.h
@@ -27,6 +27,7 @@
   F(FI_PAIR_CONSTRUCT,		'm', 'p') \
   F(FI_EC_CONSTRUCT,		'm', 'c') \
   F(FI_LC_CONSTRUCT,		'm', 'l') \
+  F(FI_PATHMASK_CONSTRUCT,	'm', 'P') \
   F(FI_NEQ,			'!', '=') \
   F(FI_EQ,			'=', '=') \
   F(FI_LT,			  0, '<') \
@@ -196,7 +197,6 @@ int f_run(struct filter *filter, struct rte **rte, struct ea_list **tmp_attrs, s
 struct f_val f_eval_rte(struct f_inst *expr, struct rte **rte, struct linpool *tmp_pool);
 struct f_val f_eval(struct f_inst *expr, struct linpool *tmp_pool);
 uint f_eval_int(struct f_inst *expr);
-u32 f_eval_asn(struct f_inst *expr);
 
 char *filter_name(struct filter *filter);
 int filter_same(struct filter *new, struct filter *old);
diff --git a/nest/a-path.c b/nest/a-path.c
index b453f702..0272c6d7 100644
--- a/nest/a-path.c
+++ b/nest/a-path.c
@@ -535,8 +535,7 @@ as_path_match(struct adata *path, struct f_path_mask *mask)
 	  val2 = val = mask->val;
 	  goto step;
 	case PM_ASN_EXPR:
-	  val2 = val = f_eval_asn((struct f_inst *) mask->val);
-	  goto step;
+	  ASSERT(0);
 	case PM_ASN_RANGE:
 	  val = mask->val;
 	  val2 = mask->val2;