eager quantifier instantiation for quantified array properties

src/muz/transforms/CMakeLists.txt

@@ -21,6 +21,8 @@ z3_add_component(transforms
     dl_mk_unbound_compressor.cpp
     dl_mk_unfold.cpp
     dl_transforms.cpp
+    dl_mk_array_eq_rewrite.cpp
+    dl_mk_array_instantiation.cpp
   COMPONENT_DEPENDENCIES
     dataflow
     hilbert

src/muz/transforms/dl_mk_array_eq_rewrite.cpp

@@ -0,0 +1,140 @@
+/*++
+
+Module Name:
+
+    dl_mk_array_eq_rewrite.h
+
+Abstract:
+    Selects a representative for array equivalence classes.
+
+Author:
+
+    Julien Braine
+
+Revision History:
+
+--*/
+
+
+#include "dl_mk_array_eq_rewrite.h"
+#include "dl_context.h"
+#include "pattern_inference.h"
+#include "dl_context.h"
+#include "expr_safe_replace.h"
+#include "expr_abstract.h"
+#include"fixedpoint_params.hpp"
+#include "../spacer/obj_equiv_class.h"
+
+namespace datalog {
+
+  mk_array_eq_rewrite::mk_array_eq_rewrite(
+        context & ctx, unsigned priority):
+        plugin(priority),
+        m(ctx.get_manager()),
+        m_ctx(ctx),
+        m_a(m)
+  {
+  }
+
+  rule_set * mk_array_eq_rewrite::operator()(rule_set const & source)
+  {
+    src_set = &source;
+    rule_set * result = alloc(rule_set, m_ctx);
+    result->inherit_predicates(source);
+    dst=result;
+    unsigned nbrules = source.get_num_rules();
+    src_manager = &source.get_rule_manager();
+    for(unsigned i =0;i<nbrules;i++)
+    {
+      rule & r = *source.get_rule(i);
+      instantiate_rule(r, *result);
+    }
+    return result;
+  }
+
+  void mk_array_eq_rewrite::instantiate_rule(const rule& r, rule_set & dest)
+  {
+    //Reset everything
+    cnt = src_manager->get_counter().get_max_rule_var(r)+1;
+
+
+    expr_ref_vector new_tail(m);
+    unsigned nb_predicates = r.get_uninterpreted_tail_size();
+    unsigned tail_size = r.get_tail_size();
+    for(unsigned i=0;i<nb_predicates;i++)
+    {
+      new_tail.push_back(r.get_tail(i));
+    }
+
+    spacer::expr_equiv_class array_eq_classes(m);
+    for(unsigned i=nb_predicates;i<tail_size;i++)
+    {
+      expr* cond = r.get_tail(i);
+      expr* e1, *e2;
+      if(m.is_eq(cond, e1, e2) && m_a.is_array(get_sort(e1)))
+      {
+        array_eq_classes.merge(e1, e2);
+      }
+      else
+      {
+        new_tail.push_back(cond);
+      }
+    }
+
+    for(spacer::expr_equiv_class::equiv_iterator c_eq = array_eq_classes.begin();
+        c_eq != array_eq_classes.end();++c_eq)
+    {
+      expr* representative = *(*c_eq).begin();
+      for(spacer::expr_equiv_class::iterator it = (*c_eq).begin();
+          it!=(*c_eq).end(); ++it)
+      {
+        if(!is_var(*it))
+        {
+          representative = *it;
+          break;
+        }
+      }
+      for(spacer::expr_equiv_class::iterator it = (*c_eq).begin();
+          it!=(*c_eq).end(); ++it)
+      {
+        for(unsigned i=0;i<new_tail.size();i++)
+          new_tail[i] = replace(new_tail[i].get(), representative, *it);
+      }
+      for(spacer::expr_equiv_class::iterator it = (*c_eq).begin();
+          it!=(*c_eq).end(); ++it)
+      {
+        new_tail.push_back(m.mk_eq(*it, representative));
+      }
+    }
+    params_ref select_over_store;
+    select_over_store.set_bool("expand_select_store", true);
+    th_rewriter t(m, select_over_store);
+    expr_ref_vector res_conjs(m);
+    for(unsigned i=0;i<new_tail.size();i++)
+    {
+      expr_ref tmp(m);
+      t(new_tail[i].get(), tmp);
+      res_conjs.push_back(tmp);
+    }
+    proof_ref pr(m);
+    src_manager->mk_rule(m.mk_implies(m.mk_and(res_conjs.size(), res_conjs.c_ptr()), r.get_head()), pr, dest, r.name());
+  }
+
+  expr* mk_array_eq_rewrite::replace(expr* e, expr* new_val, expr* old_val)
+  {
+    if(e==old_val)
+      return new_val;
+    else if(!is_app(e))
+    {
+      return e;
+    }
+    app*f = to_app(e);
+    ptr_vector<expr> n_args;
+    for(unsigned i=0;i<f->get_num_args();i++)
+    {
+      n_args.push_back(replace(f->get_arg(i), new_val, old_val));
+    }
+    return m.mk_app(f->get_decl(), n_args.size(), n_args.c_ptr());
+  }
+
+}

src/muz/transforms/dl_mk_array_eq_rewrite.h

@@ -0,0 +1,54 @@
+/*++
+
+Module Name:
+
+    dl_mk_array_eq_rewrite.h
+
+Abstract:
+    Selects a representative for array equivalence classes.
+
+Author:
+
+    Julien Braine
+
+Revision History:   
+
+--*/
+
+#ifndef DL_MK_ARRAY_EQ_REWRITE_H_
+#define DL_MK_ARRAY_EQ_REWRITE_H_
+
+
+#include "dl_rule_transformer.h"
+#include "../spacer/obj_equiv_class.h"
+
+namespace datalog {
+
+    class context;
+    class mk_array_eq_rewrite : public rule_transformer::plugin {
+       //Context objects
+       ast_manager&      m;
+       context&          m_ctx;
+       array_util   m_a;
+    
+       //Rule set context
+       const rule_set*src_set;
+       rule_set*dst;
+       rule_manager* src_manager;
+       unsigned cnt;//Index for new variables
+
+       expr* replace(expr* e, expr* new_val, expr* old_val);
+       void instantiate_rule(const rule& r, rule_set & dest);
+
+     public:
+        mk_array_eq_rewrite(context & ctx, unsigned priority);
+        rule_set * operator()(rule_set const & source);
+        virtual ~mk_array_eq_rewrite(){}
+    };
+
+
+
+};
+
+#endif /* DL_MK_ARRAY_EQ_REWRITE_H_ */
+

src/muz/transforms/dl_mk_array_instantiation.cpp

@@ -0,0 +1,324 @@
+/*++
+
+Module Name:
+
+    dl_mk_array_instantiation.h
+
+Abstract:
+
+    Does array instantiation
+
+Author:
+
+    Julien Braine
+
+Revision History:
+
+--*/
+
+
+#include "dl_mk_array_instantiation.h"
+#include "dl_context.h"
+#include "pattern_inference.h"
+#include "dl_context.h"
+#include "expr_safe_replace.h"
+#include "expr_abstract.h"
+#include"fixedpoint_params.hpp"
+#include "../spacer/obj_equiv_class.h"
+
+namespace datalog {
+
+  mk_array_instantiation::mk_array_instantiation(
+        context & ctx, unsigned priority):
+        plugin(priority),
+        m(ctx.get_manager()),
+        m_ctx(ctx),
+        m_a(m),
+        eq_classes(m),
+        ownership(m)
+  {
+  }
+
+  rule_set * mk_array_instantiation::operator()(rule_set const & source)
+  {
+    std::cout<<"Array Instantiation called with parameters :"
+             <<" enforce="<<m_ctx.get_params().xform_instantiate_arrays_enforce()
+             <<" nb_quantifier="<<m_ctx.get_params().xform_instantiate_arrays_nb_quantifier()
+             <<" slice_technique="<<m_ctx.get_params().xform_instantiate_arrays_slice_technique()
+             <<"\n";
+    std::cout<<"Input rules = \n";
+    source.display(std::cout);
+    src_set = &source;
+    rule_set * result = alloc(rule_set, m_ctx);
+    dst=result;
+    unsigned nbrules = source.get_num_rules();
+    src_manager = &source.get_rule_manager();
+    for(unsigned i =0;i<nbrules;i++)
+    {
+      rule & r = *source.get_rule(i);
+      instantiate_rule(r, *result);
+    }
+    std::cout<<"\n\nOutput rules = \n";
+    result->display(std::cout);
+    return result;
+  }
+
+  void mk_array_instantiation::instantiate_rule(const rule& r, rule_set & dest)
+  {
+    //Reset everything
+    selects.reset();
+    eq_classes.reset();
+    cnt = src_manager->get_counter().get_max_rule_var(r)+1;
+    done_selects.reset();
+    ownership.reset();
+
+    expr_ref_vector phi(m);
+    expr_ref_vector preds(m);
+    expr_ref new_head = create_head(to_app(r.get_head()));
+    unsigned nb_predicates = r.get_uninterpreted_tail_size();
+    unsigned tail_size = r.get_tail_size();
+    for(unsigned i=0;i<nb_predicates;i++)
+    {
+      preds.push_back(r.get_tail(i));
+    }
+    for(unsigned i=nb_predicates;i<tail_size;i++)
+    {
+      phi.push_back(r.get_tail(i));
+    }
+
+    //Retrieve selects
+    for(unsigned i=0;i<phi.size();i++)
+      retrieve_selects(phi[i].get());
+
+    //Rewrite the predicates
+    expr_ref_vector new_tail(m);
+    for(unsigned i=0;i<preds.size();i++)
+    {
+      new_tail.append(instantiate_pred(to_app(preds[i].get())));
+    }
+    new_tail.append(phi);
+    for(obj_map<expr, var*>::iterator it = done_selects.begin(); it!=done_selects.end(); ++it)
+    {
+      expr_ref tmp(m);
+      tmp = &it->get_key();
+      new_tail.push_back(m.mk_eq(it->get_value(), tmp));
+    }
+    proof_ref pr(m);
+    src_manager->mk_rule(m.mk_implies(m.mk_and(new_tail.size(), new_tail.c_ptr()), new_head), pr, dest, r.name());
+  }
+
+  expr_ref mk_array_instantiation::create_head(app* old_head)
+  {
+     expr_ref_vector new_args(m);
+     for(unsigned i=0;i<old_head->get_num_args();i++)
+     {
+       expr*arg = old_head->get_arg(i);
+       if(m_a.is_array(get_sort(arg)))
+       {
+         for(unsigned k=0; k< m_ctx.get_params().xform_instantiate_arrays_nb_quantifier();k++)
+         {
+           expr_ref_vector dummy_args(m);
+           dummy_args.push_back(arg);
+           for(unsigned i=0;i<get_array_arity(get_sort(arg));i++)
+           {
+             dummy_args.push_back(m.mk_var(cnt, get_array_domain(get_sort(arg), i)));
+             cnt++;
+           }
+           expr_ref select(m);
+           select = m_a.mk_select(dummy_args.size(), dummy_args.c_ptr());
+           new_args.push_back(select);
+           selects.insert_if_not_there(arg, ptr_vector<expr>());
+           selects[arg].push_back(select);
+         }
+         if(!m_ctx.get_params().xform_instantiate_arrays_enforce())
+             new_args.push_back(arg);
+       }
+       else
+        new_args.push_back(arg);
+     }
+     return create_pred(old_head, new_args);
+  }
+
+
+  void mk_array_instantiation::retrieve_selects(expr* e)
+  {
+    //If the expression is not a function application, we ignore it
+    if (!is_app(e)) {
+      return;
+    }
+    app*f=to_app(e);
+    //Call the function recursively on all arguments
+    unsigned nbargs = f->get_num_args();
+    for(unsigned i=0;i<nbargs;i++)
+    {
+      retrieve_selects(f->get_arg(i));
+    }
+    //If it is a select, then add it to selects
+    if(m_a.is_select(f))
+    {
+      SASSERT(!m_a.is_array(get_sort(e)));
+      selects.insert_if_not_there(f->get_arg(0), ptr_vector<expr>());
+      selects[f->get_arg(0)].push_back(e);
+    }
+    //If it is a condition between arrays, for example the result of a store, then add it to the equiv_classes
+    if(m_a.is_store(f))
+    {
+      eq_classes.merge(e, f->get_arg(0));
+    }
+    else if(m.is_eq(f) && m_a.is_array(get_sort(f->get_arg(0))))
+    {
+      eq_classes.merge(f->get_arg(0), f->get_arg(1));
+    }
+  }
+
+
+  expr_ref_vector mk_array_instantiation::getId(app*old_pred, const expr_ref_vector& n_args)
+  {
+    expr_ref_vector res(m);
+    for(unsigned i=0;i<n_args.size(); i++)
+    {
+      if(m_a.is_select(n_args[i]))
+      {
+        app*select = to_app(n_args[i]);
+        for(unsigned j=1;j<select->get_num_args();j++)
+        {
+          res.push_back(select->get_arg(j));
+        }
+      }
+    }
+    return res;
+  }
+
+  expr_ref mk_array_instantiation::create_pred(app*old_pred, expr_ref_vector& n_args)
+  {
+    expr_ref_vector new_args(m);
+    new_args.append(n_args);
+    new_args.append(getId(old_pred, n_args));
+    for(unsigned i=0;i<new_args.size();i++)
+    {
+      if(m_a.is_select(new_args[i].get()))
+      {
+        new_args[i] = mk_select_var(new_args[i].get());
+      }
+    }
+    sort_ref_vector new_sorts(m);
+    for(unsigned i=0;i<new_args.size();i++)
+      new_sorts.push_back(get_sort(new_args[i].get()));
+    expr_ref res(m);
+    func_decl_ref fun_decl(m);
+    fun_decl = m.mk_func_decl(symbol((old_pred->get_decl()->get_name().str()+"!inst").c_str()), new_sorts.size(), new_sorts.c_ptr(), old_pred->get_decl()->get_range());
+    m_ctx.register_predicate(fun_decl, false);
+    if(src_set->is_output_predicate(old_pred->get_decl()))
+      dst->set_output_predicate(fun_decl);
+    res=m.mk_app(fun_decl,new_args.size(), new_args.c_ptr());
+    return res;
+  }
+
+  var * mk_array_instantiation::mk_select_var(expr* select)
+  {
+    var*result;
+    if(!done_selects.find(select, result))
+    {
+      ownership.push_back(select);
+      result = m.mk_var(cnt, get_sort(select));
+      cnt++;
+      done_selects.insert(select, result);
+    }
+    return result;
+  }
+
+  expr_ref mk_array_instantiation::rewrite_select(expr*array, expr*select)
+  {
+    app*s = to_app(select);
+    expr_ref res(m);
+    expr_ref_vector args(m);
+    args.push_back(array);
+    for(unsigned i=1; i<s->get_num_args();i++)
+    {
+      args.push_back(s->get_arg(i));
+    }
+    res = m_a.mk_select(args.size(), args.c_ptr());
+    return res;
+  }
+
+  expr_ref_vector mk_array_instantiation::retrieve_all_selects(expr*array)
+  {
+    expr_ref_vector all_selects(m);
+    for(spacer::expr_equiv_class::iterator it = eq_classes.begin(array);
+        it != eq_classes.end(array); ++it)
+    {
+      selects.insert_if_not_there(*it, ptr_vector<expr>());
+      ptr_vector<expr>& select_ops = selects[*it];
+      for(unsigned i=0;i<select_ops.size();i++)
+      {
+        all_selects.push_back(rewrite_select(array, select_ops[i]));
+      }
+    }
+    if(all_selects.size()==0)
+    {
+      expr_ref_vector dummy_args(m);
+      dummy_args.push_back(array);
+      for(unsigned i=0;i<get_array_arity(get_sort(array));i++)
+      {
+        dummy_args.push_back(m.mk_var(cnt, get_array_domain(get_sort(array), i)));
+        cnt++;
+      }
+      all_selects.push_back(m_a.mk_select(dummy_args.size(), dummy_args.c_ptr()));
+    }
+    return all_selects;
+  }
+
+
+  expr_ref_vector mk_array_instantiation::instantiate_pred(app*old_pred)
+  {
+
+    unsigned nb_old_args=old_pred->get_num_args();
+    //Stores, for each old position, the list of a new possible arguments
+    vector<expr_ref_vector> arg_correspondance;
+    for(unsigned i=0;i<nb_old_args;i++)
+    {
+      expr_ref arg(old_pred->get_arg(i), m);
+      if(m_a.is_array(get_sort(arg)))
+      {
+        vector<expr_ref_vector> arg_possibilities(m_ctx.get_params().xform_instantiate_arrays_nb_quantifier(), retrieve_all_selects(arg));
+        arg_correspondance.append(arg_possibilities);
+        if(!m_ctx.get_params().xform_instantiate_arrays_enforce())
+        {
+          expr_ref_vector tmp(m);
+          tmp.push_back(arg);
+          arg_correspondance.push_back(tmp);
+        }
+      }
+      else
+      {
+        expr_ref_vector tmp(m);
+        tmp.push_back(arg);
+        arg_correspondance.push_back(tmp);
+      }
+    }
+    //Now, we need to deal with every combination
+
+    expr_ref_vector res(m);
+
+    svector<unsigned> chosen(arg_correspondance.size(), 0u);
+    while(1)
+    {
+      expr_ref_vector new_args(m);
+      for(unsigned i=0;i<chosen.size();i++)
+      {
+          new_args.push_back(arg_correspondance[i][chosen[i]].get());
+      }
+      res.push_back(create_pred(old_pred, new_args));
+      unsigned pos=-1;
+      do
+      {
+        pos++;
+        if(pos==chosen.size())
+        {
+          return res;
+        }
+      }while(chosen[pos]+1>=arg_correspondance[pos].size());
+      chosen[pos]++;
+    }
+  }
+}

src/muz/transforms/dl_mk_array_instantiation.h

@@ -0,0 +1,123 @@
+/*++
+
+Module Name:
+
+    dl_mk_array_instantiation.h
+
+Abstract:
+    Transforms predicates so that array invariants can be discovered.
+
+    Motivation   :  Given a predicate P(a), no quantifier-free solution can express that P(a) <=> forall i, P(a[i]) = 0
+
+    Solution     :  Introduce a fresh variable i, and transform P(a) into P!inst(i, a).
+                    Now, (P!inst(i,a) := a[i] = 0) <=> P(a) := forall i, a[i] = 0.
+
+                    Transformation on Horn rules:
+                    P(a, args) /\ phi(a, args, args') => P'(args') (for simplicity, assume there are no arrays in args').
+                    Is transformed into:
+                    (/\_r in read_indices(phi) P!inst(r, a, args)) /\ phi(a, args, args') => P'(args')
+
+    Limitations  :  This technique can only discover invariants on arrays that depend on one quantifier.
+    Related work :  Techniques relying on adding quantifiers and eliminating them. See dl_mk_quantifier_abstraction and dl_mk_quantifier_instantiation
+
+Implementation:
+    The implementation follows the solution suggested above, with more options. The addition of options implies that in the simple
+    case described above, we in fact have P(a) transformed into P(i, a[i], a).
+
+    1) Dealing with multiple quantifiers -> The options fixedpoint.xform.instantiate_arrays.nb_quantifier gives the number of quantifiers per array.
+
+    2) Inforcing the instantiation -> We suggest an option (enforce_instantiation) to enforce this abstraction. This transforms
+       P(a) into P(i, a[i]). This enforces the solver to limit the space search at the cost of imprecise results. This option
+       corresponds to fixedpoint.xform.instantiate_arrays.enforce
+
+    3) Adding slices in the mix -> We wish to have the possibility to further restrict the search space: we want to smash cells, given a smashing rule.
+       For example, in for loops j=0; j<n; j++, it might be relevant to restrict the search space and look for invariants that only depend on whether
+       0<=i<j or j<=i, where i is the quantified variable.
+
+       Formally, a smashing rule is a function from the Index set (usually integer) to integers (the id set).
+       GetId(i) should return the id of the set i belongs in.
+
+       In our example, we can give 0 as the id of the set {n, 0<=n<j} and 1 for the set {n, j<=n}, and -1 for the set {n, n<0}. We then have
+       GetId(i) = ite(i<0, -1, ite(i<j, 0, 1))
+
+       Given that GetId function, P(a) /\ phi(a, ...) => P'(...) is transformed into
+       (/\_r in read_indices(phi) P!inst(id_r, a[r], a) /\ GetId(r) = id_r) /\ phi(a, ...) => P'(...).
+       Note : when no slicing is done, GetId(i) = i.
+       This option corresponds to fixedpoint.xform.instantiate_arrays.slice_technique
+
+       Although we described GetId as returning integers, there is no reason to restrict the type of ids to integers. A more direct method,
+       for the 0<=i<j or j<=i case could be :
+       GetId(i) = (i<0, i<j)
+
+       GetId is even more powerful as we deal with the multiple quantifiers on multiple arrays.
+       For example, we can use GetId to look for the same quantifiers in each array.
+       Assume we have arrays a and b, instantiated with one quantifier each i and j.
+       We can have GetId(i,j) = ite(i=j, (i, true), (fresh, false))
+
+    4) Reducing the set of r in read_indices(phi): in fact, we do not need to "instantiate" on all read indices of phi,
+       we can restrict ourselves to those "linked" to a, through equalities and stores.
+
+
+Author:
+
+    Julien Braine
+
+Revision History:
+
+--*/
+
+#ifndef DL_MK_ARRAY_INSTANTIATION_H_
+#define DL_MK_ARRAY_INSTANTIATION_H_
+
+
+#include "dl_rule_transformer.h"
+#include "../spacer/obj_equiv_class.h"
+
+namespace datalog {
+
+    class context;
+    class mk_array_instantiation : public rule_transformer::plugin {
+       //Context objects
+       ast_manager&      m;
+       context&          m_ctx;
+       array_util   m_a;
+
+       //Rule set context
+       const rule_set*src_set;
+       rule_set*dst;
+       rule_manager* src_manager;
+
+       //Rule context
+       obj_map<expr, ptr_vector<expr> > selects;
+        spacer::expr_equiv_class eq_classes;
+       unsigned cnt;//Index for new variables
+       obj_map<expr, var*> done_selects;
+       expr_ref_vector ownership;
+
+       //Helper functions
+       void instantiate_rule(const rule& r, rule_set & dest);//Instantiates the rule
+       void retrieve_selects(expr* e);//Retrieves all selects (fills the selects and eq_classes members)
+       expr_ref rewrite_select(expr*array, expr*select);//Rewrites select(a, args) to select(array, args)
+       expr_ref_vector retrieve_all_selects(expr*array);//Retrieves all selects linked to a given array (using eq classes and selects)
+       expr_ref_vector instantiate_pred(app*old_pred);//Returns all the instantiation of a given predicate
+       expr_ref create_pred(app*old_pred, expr_ref_vector& new_args);//Creates a predicate
+       expr_ref create_head(app* old_head);//Creates the new head
+       var * mk_select_var(expr* select);
+
+       /*Given the old predicate, and the new arguments for the new predicate, returns the new setId arguments.
+         By default getId(P(x, y, a, b), (x, y, a[i], a[j], a, b[k], b[l], b)) (nb_quantifier=2, enforce=false)
+         returns (i,j,k,l)
+         So that the final created predicate is P!inst(x, y, a[i], a[j], a, b[k], b[l], b, i, j, k, l)
+       */
+       expr_ref_vector getId(app*old_pred, const expr_ref_vector& new_args);
+     public:
+        mk_array_instantiation(context & ctx, unsigned priority);
+        rule_set * operator()(rule_set const & source);
+        virtual ~mk_array_instantiation(){}
+    };
+
+
+
+};
+
+#endif /* DL_MK_ARRAY_INSTANTIATION_H_ */

src/muz/transforms/dl_transforms.cpp

@@ -33,7 +33,8 @@ Revision History:
 #include "muz/transforms/dl_mk_quantifier_instantiation.h"
 #include "muz/transforms/dl_mk_subsumption_checker.h"
 #include "muz/transforms/dl_mk_scale.h"
-#include"fixedpoint_params.hpp"
+#include "muz/base/fixedpoint_params.hpp"
+#include "muz/transforms/dl_mk_array_eq_rewrite.h"
 
 namespace datalog {
 
@@ -46,6 +47,11 @@ namespace datalog {
         transf.register_plugin(alloc(datalog::mk_coi_filter, ctx));
         transf.register_plugin(alloc(datalog::mk_interp_tail_simplifier, ctx));
 
+        if (ctx.get_params().xform_instantiate_arrays()) {
+            transf.register_plugin(alloc(datalog::mk_array_instantiation, ctx, 34999));
+        }
+        if(ctx.get_params().xform_transform_arrays())
+            transf.register_plugin(alloc(datalog::mk_array_eq_rewrite, ctx, 34998));
         if (ctx.get_params().xform_quantify_arrays()) {
             transf.register_plugin(alloc(datalog::mk_quantifier_abstraction, ctx, 38000));
         }
@@ -83,7 +89,7 @@ namespace datalog {
         transf.register_plugin(alloc(datalog::mk_karr_invariants, ctx, 36010));
         transf.register_plugin(alloc(datalog::mk_scale, ctx, 36030));
         if (!ctx.get_params().xform_quantify_arrays()) {
-            transf.register_plugin(alloc(datalog::mk_array_blast, ctx, 36000));
+            transf.register_plugin(alloc(datalog::mk_array_blast, ctx, 35999));
         }
         if (ctx.get_params().xform_magic()) {
             transf.register_plugin(alloc(datalog::mk_magic_symbolic, ctx, 36020));