diff --git a/ChangeLog b/ChangeLog
index 80f8076e1..57bbec670 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2007-07-23  Alexandre Duret-Lutz  <adl@src.lip6.fr>
 
+	* iface/gspn/ltlgspn.cc: New option -L.
+	* iface/gspn/ssp.cc, iface/gspn/ssp.hh (gspn_ssp_interface)
+	support for a new option "pushfront".
+
 	* NEWS, configure.in: Bump version to 0.4a.
 
 2007-07-17  Alexandre Duret-Lutz  <adl@src.lip6.fr>
diff --git a/iface/gspn/ltlgspn.cc b/iface/gspn/ltlgspn.cc
index fe4a6b410..fbcb0350e 100644
--- a/iface/gspn/ltlgspn.cc
+++ b/iface/gspn/ltlgspn.cc
@@ -1,4 +1,4 @@
-// Copyright (C) 2003, 2004, 2006 Laboratoire d'Informatique de Paris 6
+// Copyright (C) 2003, 2004, 2006, 2007 Laboratoire d'Informatique de Paris 6
 // (LIP6), département Systèmes Répartis Coopératifs (SRC),
 // Université Pierre et Marie Curie.
 //
@@ -53,6 +53,8 @@ syntax(char* prog)
 #ifdef SSP
 	    << "  -1  do not use a double hash (for inclusion check)"
 	    << std::endl
+	    << "  -L  use LIFO ordering for inclusion check"
+	    << std::endl
 #endif
 	    << "  -c  compute an example" << std::endl
 	    << "      (instead of just checking for emptiness)" << std::endl
@@ -108,6 +110,7 @@ main(int argc, char **argv)
 #ifdef SSP
       bool doublehash = true;
       bool stack_inclusion = true;
+      bool pushfront = false;
 #endif
       std::string dead = "true";
 
@@ -120,6 +123,10 @@ main(int argc, char **argv)
 	    {
 	      doublehash = false;
 	    }
+	  else if (!strcmp(argv[formula_index], "-L"))
+	    {
+	      pushfront = true;
+	    }
 	  else
 #endif
 	  if (!strcmp(argv[formula_index], "-c"))
@@ -209,7 +216,8 @@ main(int argc, char **argv)
 
 #if SSP
       bool inclusion = (check != Couvreur && check != Couvreur2);
-      spot::gspn_ssp_interface gspn(2, argv, dict, env, inclusion, doublehash);
+      spot::gspn_ssp_interface gspn(2, argv, dict, env, inclusion,
+				    doublehash, pushfront);
 
       spot::tgba_parse_error_list pel1;
       spot::tgba_explicit* control = spot::tgba_parse(argv[formula_index + 2],
diff --git a/iface/gspn/ssp.cc b/iface/gspn/ssp.cc
index 91a18b939..6d720229b 100644
--- a/iface/gspn/ssp.cc
+++ b/iface/gspn/ssp.cc
@@ -49,6 +49,7 @@ namespace spot
     }
 
     static bool doublehash;
+    static bool pushfront;
   }
 
   // state_gspn_ssp
@@ -539,10 +540,12 @@ namespace spot
 					 const
 					 ltl::declarative_environment& env,
 					 bool inclusion,
-					 bool doublehash_)
+					 bool doublehash_,
+					 bool pushfront_)
     : dict_(dict), env_(env)
   {
     doublehash = doublehash_;
+    pushfront = pushfront_;
     if (inclusion)
       inclusion_version();
 
@@ -863,7 +866,10 @@ namespace spot
       if (sg)
 	{
 	  const void* cont = container_(sg);
-	  contained[cont][s_->right()].push_front(s);
+	  if (pushfront)
+	    contained[cont][s_->right()].push_front(s);
+	  else
+	    contained[cont][s_->right()].push_back(s);
 	}
     }
 
diff --git a/iface/gspn/ssp.hh b/iface/gspn/ssp.hh
index f9f12fa09..dbb7df02f 100644
--- a/iface/gspn/ssp.hh
+++ b/iface/gspn/ssp.hh
@@ -1,4 +1,4 @@
-// Copyright (C) 2003, 2004, 2006 Laboratoire d'Informatique de
+// Copyright (C) 2003, 2004, 2006, 2007 Laboratoire d'Informatique de
 // Paris 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
 // Université Pierre et Marie Curie.
 //
@@ -41,7 +41,8 @@ namespace spot
     gspn_ssp_interface(int argc, char **argv,
 		       bdd_dict* dict, const ltl::declarative_environment& env,
 		       bool inclusion = false,
-		       bool doublehash = true);
+		       bool doublehash = true,
+		       bool pushfront = false);
     ~gspn_ssp_interface();
     tgba* automaton(const tgba* operand) const;
   private: