First draft of elim_term_ite xform. Not working.

src/muz/base/dl_context.cpp

@@ -307,6 +307,7 @@ namespace datalog {
     bool context::instantiate_quantifiers() const { return m_params->xform_instantiate_quantifiers(); }
     bool context::array_blast() const { return m_params->xform_array_blast(); }
     bool context::array_blast_full() const { return m_params->xform_array_blast_full(); }
+    bool context::elim_term_ite() const {return m_params->xform_elim_term_ite();}
 
 
     void context::register_finite_sort(sort * s, sort_kind k) {

src/muz/base/dl_context.h

@@ -280,6 +280,7 @@ namespace datalog {
         bool xform_coi() const;
         bool array_blast() const;
         bool array_blast_full() const;
+        bool elim_term_ite() const;
 
         void register_finite_sort(sort * s, sort_kind k);
 

src/muz/base/fp_params.pyg

@@ -132,10 +132,11 @@ def_module_params('fp',
                           ('spacer.use_derivations', BOOL, True, 'SPACER: using derivation mechanism to cache intermediate results for non-linear rules'),
                           ('xform.array_blast', BOOL, False, "try to eliminate local array terms using Ackermannization -- some array terms may remain"),
 	                  ('xform.array_blast_full', BOOL, False, "eliminate all local array variables by QE"),
+                          ('xform.elim_term_ite', BOOL, False, "Eliminate term-ite expressions"),
                           ('spacer.propagate', BOOL, True, 'Enable propagate/pushing phase'),
                           ('spacer.max_level', UINT, UINT_MAX, "Maximum level to explore"),
                           ('spacer.elim_aux', BOOL, True, "Eliminate auxiliary variables in reachability facts"),
-                          ('spacer.blast_term_ite', BOOL, True, "Expand non-Boolean ite-terms"),
+                          ('spacer.blast_term_ite_inflation', UINT, 3, 'Maximum inflation for non-Boolean ite-terms expansion: 0 (none), k (multiplicative)'),
                           ('spacer.reach_dnf', BOOL, True, "Restrict reachability facts to DNF"),
                           ('bmc.linear_unrolling_depth', UINT, UINT_MAX, "Maximal level to explore"),
                           ('spacer.iuc.split_farkas_literals', BOOL, False, "Split Farkas literals"),

src/muz/spacer/spacer_context.cpp

@@ -1683,7 +1683,10 @@ void pred_transformer::init_rule(decl2rel const& pts, datalog::rule const& rule)
     // rewrite and simplify
     th_rewriter rw(m);
     rw(trans);
-    if (ctx.blast_term_ite()) {blast_term_ite(trans, 3); rw(trans);}
+    if (ctx.blast_term_ite_inflation() > 0) {
+        blast_term_ite(trans, ctx.blast_term_ite_inflation());
+        rw(trans);
+    }
     TRACE("spacer_init_rule", tout << mk_pp(trans, m) << "\n";);
 
     // allow quantifiers in init rule
@@ -2265,7 +2268,7 @@ void context::updt_params() {
     m_use_euf_gen = m_params.spacer_use_euf_gen();
     m_use_ctp = m_params.spacer_ctp();
     m_use_inc_clause = m_params.spacer_use_inc_clause();
-    m_blast_term_ite = m_params.spacer_blast_term_ite();
+    m_blast_term_ite_inflation = m_params.spacer_blast_term_ite_inflation();
     m_use_ind_gen = m_params.spacer_use_inductive_generalizer();
     m_use_array_eq_gen = m_params.spacer_use_array_eq_generalizer();
     m_validate_lemmas = m_params.spacer_validate_lemmas();

src/muz/spacer/spacer_context.h

@@ -940,7 +940,6 @@ class context {
     bool                 m_use_euf_gen;
     bool                 m_use_ctp;
     bool                 m_use_inc_clause;
-    bool                 m_blast_term_ite;
     bool                 m_use_ind_gen;
     bool                 m_use_array_eq_gen;
     bool                 m_validate_lemmas;
@@ -962,6 +961,7 @@ class context {
     unsigned             m_push_pob_max_depth;
     unsigned             m_max_level;
     unsigned             m_restart_initial_threshold;
+    unsigned             m_blast_term_ite_inflation;
     scoped_ptr_vector<spacer_callback> m_callbacks;
     json_marshaller      m_json_marshaller;
 
@@ -1036,7 +1036,7 @@ public:
     bool simplify_pob() {return m_simplify_pob;}
     bool use_ctp() {return m_use_ctp;}
     bool use_inc_clause() {return m_use_inc_clause;}
-    bool blast_term_ite() {return m_blast_term_ite;}
+    unsigned blast_term_ite_inflation() {return m_blast_term_ite_inflation;}
     bool elim_aux() {return m_elim_aux;}
     bool reach_dnf() {return m_reach_dnf;}
 

src/muz/transforms/CMakeLists.txt

@@ -1,3 +1,4 @@
+
 z3_add_component(transforms
   SOURCES
     dl_mk_array_blast.cpp
@@ -23,6 +24,7 @@ z3_add_component(transforms
     dl_transforms.cpp
     dl_mk_array_eq_rewrite.cpp
     dl_mk_array_instantiation.cpp
+    dl_mk_elim_term_ite.cpp
   COMPONENT_DEPENDENCIES
     dataflow
     hilbert

src/muz/transforms/dl_mk_elim_term_ite.cpp

@@ -0,0 +1,117 @@
+/*++
+Copyright (c) 2018 Arie Gurfinkel
+
+Module Name:
+
+    dl_mk_elim_term_ite.h
+
+Abstract:
+
+   Remove term-ite expressions from the rules
+
+Author:
+
+    Arie Gurfinkel (agurfinkel)
+
+Revision History:
+
+--*/
+
+#include "muz/transforms/dl_mk_elim_term_ite.h"
+#include "tactic/core/blast_term_ite_tactic.h"
+#include "ast/ast_util.h"
+#include "tactic/tactic.h"
+#include "tactic/core/elim_term_ite_tactic.h"
+
+namespace datalog {
+    mk_elim_term_ite::mk_elim_term_ite(context & ctx, unsigned priority) :
+        rule_transformer::plugin(priority, false),
+        m_ctx(ctx),
+        m(ctx.get_manager()),
+        rm(ctx.get_rule_manager()) {}
+
+    mk_elim_term_ite::~mk_elim_term_ite() {}
+
+    bool mk_elim_term_ite::elim(rule &r, rule_set &new_rules){
+        unsigned utsz = r.get_uninterpreted_tail_size();
+        unsigned tsz = r.get_tail_size();
+        expr_ref_vector new_conjs(m);
+        expr_ref tmp(m);
+
+        bool change = false;
+
+        for (unsigned i = utsz; i < tsz; ++i)
+            new_conjs.push_back(r.get_tail(i));
+        flatten_and(new_conjs);
+
+        expr_ref fml1(m), fml2(m), old_body(m), body(m), head(m);
+
+        // blast ite
+        old_body = m.mk_and(new_conjs.size(), new_conjs.c_ptr());
+        body = old_body;
+        blast_term_ite(body, 2);
+        change = old_body != body;
+        if (!change) {
+            new_rules.add_rule(&r);
+            return false;
+        }
+        new_conjs.reset();
+
+        // elim ite
+        tactic_ref elim_term_ite = mk_elim_term_ite_tactic(m);
+        goal_ref goal = alloc(class goal, m);
+        goal_ref_buffer result;
+        flatten_and(body, new_conjs);
+        for (auto *e : new_conjs) {
+            goal->assert_expr(e);
+        }
+        unsigned sz = goal->num_exprs();
+        (*elim_term_ite)(goal, result);
+        if (result.size() == 1) {
+            goal_ref new_goal = result[0];
+            if (new_goal->num_exprs() != sz) {
+                new_conjs.reset();
+                new_goal->get_formulas(new_conjs);
+            }
+        }
+
+
+        expr_ref_vector conjs(m);
+        for (unsigned i = 0; i < utsz; ++i)
+            conjs.push_back(r.get_tail(i));
+        conjs.append(new_conjs);
+
+        body = mk_and(conjs);
+        head = r.get_head();
+
+        fml2 = m.mk_implies(body, head);
+        proof_ref p(m);
+        rm.mk_rule(fml2, p, new_rules, r.name());
+
+        return true;
+    }
+
+
+
+    rule_set * mk_elim_term_ite::operator()(rule_set const & source) {
+        if (!m_ctx.elim_term_ite ()) {return nullptr;}
+
+        rule_set* rules = alloc(rule_set, m_ctx);
+        rules->inherit_predicates(source);
+        bool change = false;
+        for (auto *rule : source) {
+            if (m_ctx.canceled()) {
+                change = false;
+                break;
+            }
+            change |= elim(*rule, *rules);
+        }
+        if (!change) {
+            dealloc(rules);
+            rules = nullptr;
+        }
+        return rules;
+    }
+
+
+}

src/muz/transforms/dl_mk_elim_term_ite.h

@@ -0,0 +1,38 @@
+/*++
+Copyright (c) 2018 Arie Gurfinkel
+
+Module Name:
+
+    dl_mk_elim_term_ite.h
+
+Abstract:
+
+   Remove term-ite expressions from the rules
+
+Author:
+
+    Arie Gurfinkel (agurfinkel)
+
+Revision History:
+
+--*/
+#pragma once
+
+#include "muz/base/dl_context.h"
+#include "muz/base/dl_rule_set.h"
+#include "muz/base/dl_rule_transformer.h"
+#include "tactic/equiv_proof_converter.h"
+
+namespace datalog {
+    class mk_elim_term_ite : public rule_transformer::plugin {
+        context &m_ctx;
+        ast_manager &m;
+        rule_manager &rm;
+
+        bool elim(rule &r, rule_set &new_rules);
+    public:
+        mk_elim_term_ite(context &ctx, unsigned priority);
+        ~mk_elim_term_ite() override;
+        rule_set * operator()(const rule_set &source) override;
+    };
+}

src/muz/transforms/dl_transforms.cpp

@@ -35,6 +35,7 @@ Revision History:
 #include "muz/transforms/dl_mk_scale.h"
 #include "muz/transforms/dl_mk_array_eq_rewrite.h"
 #include "muz/transforms/dl_mk_array_instantiation.h"
+#include "muz/transforms/dl_mk_elim_term_ite.h"
 #include "muz/base/fp_params.hpp"
 
 namespace datalog {
@@ -95,6 +96,8 @@ namespace datalog {
         if (ctx.get_params().xform_magic()) {
             transf.register_plugin(alloc(datalog::mk_magic_symbolic, ctx, 36020));
         }
+
+        transf.register_plugin(alloc(datalog::mk_elim_term_ite, ctx, 34999));
         ctx.transform_rules(transf);
     }
 }