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			917 lines
		
	
	
	
		
			26 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			917 lines
		
	
	
	
		
			26 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*++
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Copyright (c) 2011 Microsoft Corporation
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Module Name:
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    model_implicant.cpp
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Abstract:
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    Facility to extract prime implicant from model.
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Author:
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    Krystof Hoder (t-khoder) 2011-8-19.
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Revision History:
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Notes: 
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--*/
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#include <sstream>
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#include "array_decl_plugin.h"
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#include "ast_pp.h"
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#include "bool_rewriter.h"
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#include "for_each_expr.h"
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#include "model.h"
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#include "ref_vector.h"
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#include "rewriter.h"
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#include "rewriter_def.h"
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#include "util.h"
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#include "model_implicant.h"
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#include "arith_decl_plugin.h"
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#include "expr_replacer.h"
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#include "model_smt2_pp.h"
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#include "poly_rewriter.h"
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#include "poly_rewriter_def.h"
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#include "arith_rewriter.h"
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#include "scoped_proof.h"
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/////////////////////////
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// model_implicant
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//
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void model_implicant::assign_value(expr* e, expr* val) {
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    rational r;
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    if (m.is_true(val)) {
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        set_true(e);
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    }
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    else if (m.is_false(val)) {
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        set_false(e);
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    }
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    else if (m_arith.is_numeral(val, r)) {
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        set_number(e, r);
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    }
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    else if (m.is_value(val)) {
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        set_value(e, val);
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    }
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    else {
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        IF_VERBOSE(3, verbose_stream() << "Not evaluated " << mk_pp(e, m) << " := " << mk_pp(val, m) << "\n";);
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        TRACE("pdr", tout << "Variable is not tracked: " << mk_pp(e, m) << " := " << mk_pp(val, m) << "\n";);
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        set_x(e);
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    }
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}
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void model_implicant::setup_model(model_ref& model) {
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    m_numbers.reset();
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    m_values.reset();
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    m_model = model;
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    rational r;
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    unsigned sz = model->get_num_constants();
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    for (unsigned i = 0; i < sz; i++) {
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        func_decl * d = model->get_constant(i); 
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        expr* val = model->get_const_interp(d);
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        expr* e = m.mk_const(d);
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        m_refs.push_back(e);
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        assign_value(e, val);
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    }
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}
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void model_implicant::reset() {
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    m1.reset();
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    m2.reset();
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    m_values.reset();
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    m_visited.reset();
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    m_numbers.reset();
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    m_refs.reset();
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    m_model = 0;
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}
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expr_ref_vector model_implicant::minimize_model(ptr_vector<expr> const & formulas, model_ref& mdl) {
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    setup_model(mdl);
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    TRACE("pdr_verbose", 
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          tout << "formulas:\n";
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          for (unsigned i = 0; i < formulas.size(); ++i) tout << mk_pp(formulas[i], m) << "\n"; 
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          );
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    expr_ref_vector model = prune_by_cone_of_influence(formulas);
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    TRACE("pdr_verbose",
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          tout << "pruned model:\n";
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          for (unsigned i = 0; i < model.size(); ++i) tout << mk_pp(model[i].get(), m) << "\n";);
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    reset();
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    DEBUG_CODE(
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        setup_model(mdl);
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        VERIFY(check_model(formulas));
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        reset(););
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    return model;
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}
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expr_ref_vector model_implicant::minimize_literals(ptr_vector<expr> const& formulas, model_ref& mdl) {
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    TRACE("pdr", 
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          tout << "formulas:\n";
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          for (unsigned i = 0; i < formulas.size(); ++i) tout << mk_pp(formulas[i], m) << "\n"; 
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          );
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    expr_ref_vector result(m);
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    expr_ref tmp(m);
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    ptr_vector<expr> tocollect;
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    setup_model(mdl);
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    collect(formulas, tocollect);
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    for (unsigned i = 0; i < tocollect.size(); ++i) {
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        expr* e = tocollect[i];
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        expr* e1, *e2;
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        SASSERT(m.is_bool(e));
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        SASSERT(is_true(e) || is_false(e));
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        if (is_true(e)) {
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            result.push_back(e);
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        }
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        // hack to break disequalities for arithmetic variables.
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        else if (m.is_eq(e, e1, e2) && m_arith.is_int_real(e1)) {
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            if (get_number(e1) < get_number(e2)) {
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                result.push_back(m_arith.mk_lt(e1,e2));
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            }
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            else {
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                result.push_back(m_arith.mk_lt(e2,e1));
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            }
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        }
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        else {
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            result.push_back(m.mk_not(e));
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        }
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    }
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    reset();
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    TRACE("pdr", 
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          tout << "minimized model:\n";
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          for (unsigned i = 0; i < result.size(); ++i) tout << mk_pp(result[i].get(), m) << "\n"; 
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          );
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    return result;
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}
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void model_implicant::process_formula(app* e, ptr_vector<expr>& todo, ptr_vector<expr>& tocollect) {
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    SASSERT(m.is_bool(e));
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    SASSERT(is_true(e) || is_false(e));
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    unsigned v = is_true(e);
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    unsigned sz = e->get_num_args();
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    expr* const* args = e->get_args();
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    if (e->get_family_id() == m.get_basic_family_id()) {
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        switch(e->get_decl_kind()) {
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        case OP_TRUE:
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            break;
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        case OP_FALSE:
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            break;
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        case OP_EQ:
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        case OP_IFF:
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            if (args[0] == args[1]) {
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                SASSERT(v);
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                // no-op                    
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            }
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            else if (m.is_bool(args[0])) {
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                todo.append(sz, args);
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            }
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            else {
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                tocollect.push_back(e);
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            }
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            break;                              
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        case OP_DISTINCT:
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            tocollect.push_back(e);
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            break;
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        case OP_ITE:
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            if (args[1] == args[2]) {
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                tocollect.push_back(args[1]);
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            }
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            else if (is_true(args[1]) && is_true(args[2])) {
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                todo.append(2, args+1);
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            }
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            else if (is_false(args[1]) && is_false(args[2])) {
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                todo.append(2, args+1);
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            }
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            else if (is_true(args[0])) {
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                todo.append(2, args);
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            }
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            else {
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                SASSERT(is_false(args[0]));
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                todo.push_back(args[0]);
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                todo.push_back(args[2]);
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            }
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            break;
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        case OP_AND:
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            if (v) {
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                todo.append(sz, args);
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            }
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            else {
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                unsigned i = 0;
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                for (; !is_false(args[i]) && i < sz; ++i);     
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                if (i == sz) {
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                    fatal_error(1);
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                }
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                VERIFY(i < sz);
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                todo.push_back(args[i]);
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            }
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            break;
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        case OP_OR:
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            if (v) {
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                unsigned i = 0;
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                for (; !is_true(args[i]) && i < sz; ++i);
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                if (i == sz) {
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                    fatal_error(1);
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                }
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                VERIFY(i < sz);
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                todo.push_back(args[i]);
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            }
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            else {
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                todo.append(sz, args);
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            }
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            break;
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        case OP_XOR: 
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        case OP_NOT:
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            todo.append(sz, args);
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            break;
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        case OP_IMPLIES:
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            if (v) {
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                if (is_true(args[1])) {
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                    todo.push_back(args[1]);
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                }
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                else if (is_false(args[0])) {
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                    todo.push_back(args[0]);
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                }
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                else {
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                    IF_VERBOSE(0, verbose_stream() << "Term not handled " << mk_pp(e, m) << "\n";);
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                    UNREACHABLE();
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                }
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            }
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            else {
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                todo.append(sz, args);
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            }
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            break;
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        default:
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            IF_VERBOSE(0, verbose_stream() << "Term not handled " << mk_pp(e, m) << "\n";);
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            UNREACHABLE();
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        }
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    }
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    else {
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        tocollect.push_back(e);
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    }
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}
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void model_implicant::collect(ptr_vector<expr> const& formulas, ptr_vector<expr>& tocollect) {
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    ptr_vector<expr> todo;
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    todo.append(formulas);
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    m_visited.reset();
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    VERIFY(check_model(formulas));
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    while (!todo.empty()) {
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        app*  e = to_app(todo.back());
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        todo.pop_back();
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        if (!m_visited.is_marked(e)) {
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            process_formula(e, todo, tocollect);
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            m_visited.mark(e, true);
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        }
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    }
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    m_visited.reset();
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}
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expr_ref_vector model_implicant::prune_by_cone_of_influence(ptr_vector<expr> const & formulas) {
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    ptr_vector<expr> tocollect;
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    collect(formulas, tocollect);
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    m1.reset();
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    m2.reset();
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    for (unsigned i = 0; i < tocollect.size(); ++i) {     
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        TRACE("pdr_verbose", tout << "collect: " << mk_pp(tocollect[i], m) << "\n";);
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        for_each_expr(*this, m_visited, tocollect[i]);
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    }
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    unsigned sz = m_model->get_num_constants();
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    expr_ref e(m), eq(m), val(m);
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    expr_ref_vector model(m);
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    for (unsigned i = 0; i < sz; i++) {
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        e = m.mk_const(m_model->get_constant(i));
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        if (m_visited.is_marked(e)) {
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            val = eval(m_model, e);
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            eq = m.mk_eq(e, val);
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            model.push_back(eq);
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        }
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    }
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    m_visited.reset();
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    TRACE("pdr", tout << sz << " ==> " << model.size() << "\n";);
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    return model;
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}
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void model_implicant::eval_arith(app* e) {
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    rational r, r2;
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#define ARG1 e->get_arg(0)
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#define ARG2 e->get_arg(1)     
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    unsigned arity = e->get_num_args();
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    for (unsigned i = 0; i < arity; ++i) {
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        expr* arg = e->get_arg(i);
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        if (is_x(arg)) {
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            set_x(e);
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            return;
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        }
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        SASSERT(!is_unknown(arg));
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    }
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    switch(e->get_decl_kind()) {
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    case OP_NUM: 
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        VERIFY(m_arith.is_numeral(e, r));
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        set_number(e, r);
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        break;                
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    case OP_IRRATIONAL_ALGEBRAIC_NUM:  
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        set_x(e);
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        break;
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    case OP_LE:
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        set_bool(e, get_number(ARG1) <= get_number(ARG2));
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        break;
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    case OP_GE:
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        set_bool(e, get_number(ARG1) >= get_number(ARG2));
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        break;
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    case OP_LT:
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        set_bool(e, get_number(ARG1) < get_number(ARG2));
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        break;
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    case OP_GT:
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        set_bool(e, get_number(ARG1) > get_number(ARG2));
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        break;
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    case OP_ADD: 
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        r = rational::zero();
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        for (unsigned i = 0; i < arity; ++i) {
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            r += get_number(e->get_arg(i));
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        }
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        set_number(e, r);
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        break;                                    
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    case OP_SUB: 
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        r = get_number(e->get_arg(0));
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        for (unsigned i = 1; i < arity; ++i) {
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            r -= get_number(e->get_arg(i));
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        }
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        set_number(e, r);
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        break;                            
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    case OP_UMINUS: 
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        SASSERT(arity == 1);
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        set_number(e, get_number(e->get_arg(0)));
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        break;                
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    case OP_MUL: 
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        r = rational::one();
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        for (unsigned i = 0; i < arity; ++i) {
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            r *= get_number(e->get_arg(i));
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        }
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        set_number(e, r);
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        break;                
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    case OP_DIV: 
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        SASSERT(arity == 2);
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						|
        r = get_number(ARG2);
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						|
        if (r.is_zero()) {
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            set_x(e);
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        }
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        else {
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            set_number(e, get_number(ARG1) / r);
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						|
        }
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        break;                
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						|
    case OP_IDIV: 
 | 
						|
        SASSERT(arity == 2);
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						|
        r = get_number(ARG2);
 | 
						|
        if (r.is_zero()) {
 | 
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            set_x(e);
 | 
						|
        }
 | 
						|
        else {
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						|
            set_number(e, div(get_number(ARG1), r));
 | 
						|
        }
 | 
						|
        break;                
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						|
    case OP_REM: 
 | 
						|
        // rem(v1,v2) = if v2 >= 0 then mod(v1,v2) else -mod(v1,v2)
 | 
						|
        SASSERT(arity == 2);
 | 
						|
        r = get_number(ARG2);
 | 
						|
        if (r.is_zero()) {
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            r2 = mod(get_number(ARG1), r);
 | 
						|
            if (r.is_neg()) r2.neg();
 | 
						|
            set_number(e, r2);
 | 
						|
        }
 | 
						|
        break;
 | 
						|
    case OP_MOD: 
 | 
						|
        SASSERT(arity == 2);
 | 
						|
        r = get_number(ARG2);
 | 
						|
        if (r.is_zero()) {
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            set_number(e, mod(get_number(ARG1), r));
 | 
						|
        }
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						|
        break;                   
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						|
    case OP_TO_REAL: 
 | 
						|
        SASSERT(arity == 1);
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						|
        set_number(e, get_number(ARG1));
 | 
						|
        break;                
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						|
    case OP_TO_INT: 
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						|
        SASSERT(arity == 1);
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						|
        set_number(e, floor(get_number(ARG1)));
 | 
						|
        break;                
 | 
						|
    case OP_IS_INT: 
 | 
						|
        SASSERT(arity == 1);
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						|
        set_bool(e, get_number(ARG1).is_int());
 | 
						|
        break;
 | 
						|
    case OP_POWER:
 | 
						|
        set_x(e);
 | 
						|
        break;
 | 
						|
    default:
 | 
						|
        IF_VERBOSE(0, verbose_stream() << "Term not handled " << mk_pp(e, m) << "\n";);
 | 
						|
        UNREACHABLE();
 | 
						|
        break;
 | 
						|
    }
 | 
						|
}
 | 
						|
 | 
						|
void model_implicant::inherit_value(expr* e, expr* v) {
 | 
						|
    expr* w;
 | 
						|
    SASSERT(!is_unknown(v));
 | 
						|
    SASSERT(m.get_sort(e) == m.get_sort(v));
 | 
						|
    if (is_x(v)) {
 | 
						|
        set_x(e);
 | 
						|
    }
 | 
						|
    else if (m.is_bool(e)) {
 | 
						|
        SASSERT(m.is_bool(v));
 | 
						|
        if (is_true(v)) set_true(e);
 | 
						|
        else if (is_false(v)) set_false(e);
 | 
						|
        else {
 | 
						|
            TRACE("pdr", tout << "not inherited:\n" << mk_pp(e, m) << "\n" << mk_pp(v, m) << "\n";);
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
    }
 | 
						|
    else if (m_arith.is_int_real(e)) {
 | 
						|
        set_number(e, get_number(v));
 | 
						|
    }
 | 
						|
    else if (m.is_value(v)) {
 | 
						|
        set_value(e, v);
 | 
						|
    }
 | 
						|
    else if (m_values.find(v, w)) {
 | 
						|
        set_value(e, w);
 | 
						|
    }
 | 
						|
    else {
 | 
						|
        TRACE("pdr", tout << "not inherited:\n" << mk_pp(e, m) << "\n" << mk_pp(v, m) << "\n";);
 | 
						|
        set_x(e);
 | 
						|
    }
 | 
						|
}
 | 
						|
 | 
						|
void model_implicant::eval_exprs(expr_ref_vector& es) {
 | 
						|
    model_ref mr(m_model);
 | 
						|
    for (unsigned j = 0; j < es.size(); ++j) {
 | 
						|
        if (m_array.is_as_array(es[j].get())) {
 | 
						|
            es[j] = eval(mr, es[j].get());
 | 
						|
        }
 | 
						|
    }
 | 
						|
}
 | 
						|
 | 
						|
bool model_implicant::extract_array_func_interp(expr* a, vector<expr_ref_vector>& stores, expr_ref& else_case) {
 | 
						|
    SASSERT(m_array.is_array(a));
 | 
						|
    
 | 
						|
    TRACE("pdr", tout << mk_pp(a, m) << "\n";);
 | 
						|
    while (m_array.is_store(a)) {
 | 
						|
        expr_ref_vector store(m);
 | 
						|
        store.append(to_app(a)->get_num_args()-1, to_app(a)->get_args()+1);
 | 
						|
        eval_exprs(store);
 | 
						|
        stores.push_back(store);
 | 
						|
        a = to_app(a)->get_arg(0);
 | 
						|
    }
 | 
						|
    
 | 
						|
    if (m_array.is_const(a)) {
 | 
						|
        else_case = to_app(a)->get_arg(0);
 | 
						|
        return true;
 | 
						|
    }
 | 
						|
    
 | 
						|
    while (m_array.is_as_array(a)) {
 | 
						|
        func_decl* f = m_array.get_as_array_func_decl(to_app(a));
 | 
						|
        func_interp* g = m_model->get_func_interp(f);
 | 
						|
        unsigned sz = g->num_entries();
 | 
						|
        unsigned arity = f->get_arity();
 | 
						|
        for (unsigned i = 0; i < sz; ++i) {
 | 
						|
            expr_ref_vector store(m);
 | 
						|
            func_entry const* fe = g->get_entry(i);
 | 
						|
            store.append(arity, fe->get_args());
 | 
						|
            store.push_back(fe->get_result());
 | 
						|
            for (unsigned j = 0; j < store.size(); ++j) {
 | 
						|
                if (!is_ground(store[j].get())) {
 | 
						|
                    TRACE("pdr", tout << "could not extract array interpretation: " << mk_pp(a, m) << "\n" << mk_pp(store[j].get(), m) << "\n";);
 | 
						|
                    return false;
 | 
						|
                }
 | 
						|
            }
 | 
						|
            eval_exprs(store);
 | 
						|
            stores.push_back(store);
 | 
						|
        }        
 | 
						|
        else_case = g->get_else();
 | 
						|
        if (!else_case) {
 | 
						|
            TRACE("pdr", tout << "no else case " << mk_pp(a, m) << "\n";);
 | 
						|
            return false;
 | 
						|
        }
 | 
						|
        if (!is_ground(else_case)) {
 | 
						|
            TRACE("pdr", tout << "non-ground else case " << mk_pp(a, m) << "\n" << mk_pp(else_case, m) << "\n";);
 | 
						|
            return false;
 | 
						|
        }
 | 
						|
        if (m_array.is_as_array(else_case)) {
 | 
						|
            model_ref mr(m_model);
 | 
						|
            else_case = eval(mr, else_case);
 | 
						|
        }
 | 
						|
        TRACE("pdr", tout << "else case: " << mk_pp(else_case, m) << "\n";);
 | 
						|
        return true;
 | 
						|
    }
 | 
						|
    TRACE("pdr", tout << "no translation: " << mk_pp(a, m) << "\n";);
 | 
						|
    
 | 
						|
    return false;
 | 
						|
}
 | 
						|
 | 
						|
/**
 | 
						|
   best effort evaluator of extensional array equality.
 | 
						|
*/
 | 
						|
void model_implicant::eval_array_eq(app* e, expr* arg1, expr* arg2) {
 | 
						|
    TRACE("pdr", tout << "array equality: " << mk_pp(e, m) << "\n";);
 | 
						|
    expr_ref v1(m), v2(m);
 | 
						|
    m_model->eval(arg1, v1);
 | 
						|
    m_model->eval(arg2, v2);
 | 
						|
    if (v1 == v2) {
 | 
						|
        set_true(e);
 | 
						|
        return;
 | 
						|
    }
 | 
						|
    sort* s = m.get_sort(arg1);
 | 
						|
    sort* r = get_array_range(s);
 | 
						|
    // give up evaluating finite domain/range arrays
 | 
						|
    if (!r->is_infinite() && !r->is_very_big() && !s->is_infinite() && !s->is_very_big()) {
 | 
						|
        TRACE("pdr", tout << "equality is unknown: " << mk_pp(e, m) << "\n";);
 | 
						|
        set_x(e);
 | 
						|
        return;
 | 
						|
    }
 | 
						|
    vector<expr_ref_vector> store;
 | 
						|
    expr_ref else1(m), else2(m);
 | 
						|
    if (!extract_array_func_interp(v1, store, else1) ||
 | 
						|
        !extract_array_func_interp(v2, store, else2)) {
 | 
						|
        TRACE("pdr", tout << "equality is unknown: " << mk_pp(e, m) << "\n";);
 | 
						|
        set_x(e);
 | 
						|
        return;
 | 
						|
    }
 | 
						|
 | 
						|
    if (else1 != else2) {
 | 
						|
        if (m.is_value(else1) && m.is_value(else2)) {
 | 
						|
            TRACE("pdr", tout 
 | 
						|
                  << "defaults are different: " << mk_pp(e, m) << " " 
 | 
						|
                  << mk_pp(else1, m) << " " << mk_pp(else2, m) << "\n";);
 | 
						|
            set_false(e);
 | 
						|
        }
 | 
						|
        else if (m_array.is_array(else1)) {
 | 
						|
            eval_array_eq(e, else1, else2);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            TRACE("pdr", tout << "equality is unknown: " << mk_pp(e, m) << "\n";);
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        return;
 | 
						|
    }
 | 
						|
 | 
						|
    expr_ref s1(m), s2(m), w1(m), w2(m);        
 | 
						|
    expr_ref_vector args1(m), args2(m);
 | 
						|
    args1.push_back(v1);
 | 
						|
    args2.push_back(v2);        
 | 
						|
    for (unsigned i = 0; i < store.size(); ++i) {
 | 
						|
        args1.resize(1);
 | 
						|
        args2.resize(1);
 | 
						|
        args1.append(store[i].size()-1, store[i].c_ptr());
 | 
						|
        args2.append(store[i].size()-1, store[i].c_ptr());
 | 
						|
        s1 = m_array.mk_select(args1.size(), args1.c_ptr());
 | 
						|
        s2 = m_array.mk_select(args2.size(), args2.c_ptr());
 | 
						|
        m_model->eval(s1, w1);
 | 
						|
        m_model->eval(s2, w2);
 | 
						|
        if (w1 == w2) {
 | 
						|
            continue;
 | 
						|
        }
 | 
						|
        if (m.is_value(w1) && m.is_value(w2)) {
 | 
						|
            TRACE("pdr", tout << "Equality evaluation: " << mk_pp(e, m) << "\n"; 
 | 
						|
                  tout << mk_pp(s1, m) << " |-> " << mk_pp(w1, m) << "\n";
 | 
						|
                  tout << mk_pp(s2, m) << " |-> " << mk_pp(w2, m) << "\n";);
 | 
						|
            set_false(e);
 | 
						|
        }
 | 
						|
        else if (m_array.is_array(w1)) {
 | 
						|
            eval_array_eq(e, w1, w2);
 | 
						|
            if (is_true(e)) {
 | 
						|
                continue;
 | 
						|
            }
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            TRACE("pdr", tout << "equality is unknown: " << mk_pp(e, m) << "\n";);
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        return;
 | 
						|
    }
 | 
						|
    set_true(e);
 | 
						|
}
 | 
						|
 | 
						|
void model_implicant::eval_eq(app* e, expr* arg1, expr* arg2) {
 | 
						|
    if (arg1 == arg2) {
 | 
						|
        set_true(e);
 | 
						|
    }
 | 
						|
    else if (m_array.is_array(arg1)) {
 | 
						|
        eval_array_eq(e, arg1, arg2);
 | 
						|
    }
 | 
						|
    else if (is_x(arg1) || is_x(arg2)) {
 | 
						|
        expr_ref eq(m), vl(m);
 | 
						|
        eq = m.mk_eq(arg1, arg2);
 | 
						|
        m_model->eval(eq, vl);
 | 
						|
        if (m.is_true(vl)) {
 | 
						|
            set_bool(e, true);                
 | 
						|
        }
 | 
						|
        else if (m.is_false(vl)) {
 | 
						|
            set_bool(e, false);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            TRACE("pdr", tout << "cannot evaluate: " << mk_pp(vl, m) <<  "\n";);
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
    }
 | 
						|
    else if (m.is_bool(arg1)) {
 | 
						|
        bool val = is_true(arg1) == is_true(arg2);
 | 
						|
        SASSERT(val == (is_false(arg1) == is_false(arg2)));
 | 
						|
        if (val) {
 | 
						|
            set_true(e);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            set_false(e);
 | 
						|
        }            
 | 
						|
    }
 | 
						|
    else if (m_arith.is_int_real(arg1)) {
 | 
						|
        set_bool(e, get_number(arg1) == get_number(arg2));
 | 
						|
    }
 | 
						|
    else {
 | 
						|
        expr* e1 = get_value(arg1);
 | 
						|
        expr* e2 = get_value(arg2);
 | 
						|
        if (m.is_value(e1) && m.is_value(e2)) {
 | 
						|
            set_bool(e, e1 == e2);
 | 
						|
        }
 | 
						|
        else if (e1 == e2) {
 | 
						|
            set_bool(e, true);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            TRACE("pdr", tout << "not value equal:\n" << mk_pp(e1, m) << "\n" << mk_pp(e2, m) << "\n";);
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
    }
 | 
						|
}
 | 
						|
 | 
						|
void model_implicant::eval_basic(app* e) {
 | 
						|
    expr* arg1, *arg2;
 | 
						|
    expr *argCond, *argThen, *argElse, *arg;
 | 
						|
    bool has_x = false;
 | 
						|
    unsigned arity = e->get_num_args();
 | 
						|
    switch(e->get_decl_kind()) {
 | 
						|
    case OP_AND: 
 | 
						|
        for (unsigned j = 0; j < arity; ++j) {
 | 
						|
            expr * arg = e->get_arg(j);
 | 
						|
            if (is_false(arg)) {
 | 
						|
                set_false(e);
 | 
						|
                return;
 | 
						|
            }
 | 
						|
            else if (is_x(arg)) {
 | 
						|
                has_x = true;
 | 
						|
            }
 | 
						|
            else {
 | 
						|
                SASSERT(is_true(arg));
 | 
						|
            }
 | 
						|
        }
 | 
						|
        if (has_x) {
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            set_true(e);
 | 
						|
        }
 | 
						|
        break;
 | 
						|
    case OP_OR: 
 | 
						|
        for (unsigned j = 0; j < arity; ++j) {
 | 
						|
            expr * arg = e->get_arg(j);
 | 
						|
            if (is_true(arg)) {
 | 
						|
                set_true(e);
 | 
						|
                return;
 | 
						|
            }
 | 
						|
            else if (is_x(arg)) {
 | 
						|
                has_x = true;
 | 
						|
            }
 | 
						|
            else {
 | 
						|
                SASSERT(is_false(arg));
 | 
						|
            }
 | 
						|
        }
 | 
						|
        if (has_x) {
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            set_false(e);
 | 
						|
        }
 | 
						|
        break;
 | 
						|
    case OP_NOT: 
 | 
						|
        VERIFY(m.is_not(e, arg));
 | 
						|
        if (is_true(arg)) {
 | 
						|
            set_false(e);
 | 
						|
        }
 | 
						|
        else if (is_false(arg)) {
 | 
						|
            set_true(e);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            SASSERT(is_x(arg));
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        break;
 | 
						|
    case OP_IMPLIES: 
 | 
						|
        VERIFY(m.is_implies(e, arg1, arg2));
 | 
						|
        if (is_false(arg1) || is_true(arg2)) {
 | 
						|
            set_true(e);
 | 
						|
        }
 | 
						|
        else if (arg1 == arg2) {
 | 
						|
            set_true(e);
 | 
						|
        }
 | 
						|
        else if (is_true(arg1) && is_false(arg2)) {
 | 
						|
            set_false(e);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            SASSERT(is_x(arg1) || is_x(arg2));
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        break;
 | 
						|
    case OP_IFF: 
 | 
						|
        VERIFY(m.is_iff(e, arg1, arg2));
 | 
						|
        eval_eq(e, arg1, arg2);
 | 
						|
        break;
 | 
						|
    case OP_ITE: 
 | 
						|
        VERIFY(m.is_ite(e, argCond, argThen, argElse));
 | 
						|
        if (is_true(argCond)) { 
 | 
						|
            inherit_value(e, argThen);
 | 
						|
        }
 | 
						|
        else if (is_false(argCond)) {
 | 
						|
            inherit_value(e, argElse);
 | 
						|
        }
 | 
						|
        else if (argThen == argElse) {
 | 
						|
            inherit_value(e, argThen);
 | 
						|
        }
 | 
						|
        else if (m.is_bool(e)) {
 | 
						|
            SASSERT(is_x(argCond));
 | 
						|
            if (is_x(argThen) || is_x(argElse)) {
 | 
						|
                set_x(e);
 | 
						|
            }
 | 
						|
            else if (is_true(argThen) == is_true(argElse)) {
 | 
						|
                inherit_value(e, argThen);
 | 
						|
            }
 | 
						|
            else {
 | 
						|
                set_x(e);
 | 
						|
            }
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            set_x(e);
 | 
						|
        }
 | 
						|
        break;
 | 
						|
    case OP_TRUE:
 | 
						|
        set_true(e);
 | 
						|
        break;
 | 
						|
    case OP_FALSE:
 | 
						|
        set_false(e);
 | 
						|
        break;
 | 
						|
    case OP_EQ:
 | 
						|
        VERIFY(m.is_eq(e, arg1, arg2));
 | 
						|
        eval_eq(e, arg1, arg2);
 | 
						|
        break;
 | 
						|
    case OP_DISTINCT: {
 | 
						|
        vector<rational> values;
 | 
						|
        for (unsigned i = 0; i < arity; ++i) {
 | 
						|
            expr* arg = e->get_arg(i);
 | 
						|
            if (is_x(arg)) {
 | 
						|
                set_x(e);
 | 
						|
                return;
 | 
						|
            }
 | 
						|
            values.push_back(get_number(arg));
 | 
						|
        }
 | 
						|
        std::sort(values.begin(), values.end());
 | 
						|
        for (unsigned i = 0; i + 1 < values.size(); ++i) {
 | 
						|
            if (values[i] == values[i+1]) {
 | 
						|
                set_false(e);
 | 
						|
                return;
 | 
						|
            }
 | 
						|
        }
 | 
						|
        set_true(e);
 | 
						|
        break;
 | 
						|
    }
 | 
						|
    default:
 | 
						|
        IF_VERBOSE(0, verbose_stream() << "Term not handled " << mk_pp(e, m) << "\n";);
 | 
						|
        UNREACHABLE();        
 | 
						|
    }
 | 
						|
}
 | 
						|
    
 | 
						|
bool model_implicant::check_model(ptr_vector<expr> const& formulas) {
 | 
						|
    ptr_vector<expr> todo(formulas);
 | 
						|
        
 | 
						|
    while (!todo.empty()) {
 | 
						|
        expr * curr_e = todo.back();
 | 
						|
            
 | 
						|
        if (!is_app(curr_e)) { 
 | 
						|
            todo.pop_back();
 | 
						|
            continue;
 | 
						|
        }
 | 
						|
        app * curr = to_app(curr_e);
 | 
						|
            
 | 
						|
        if (!is_unknown(curr)) { 
 | 
						|
            todo.pop_back();
 | 
						|
            continue;
 | 
						|
        }
 | 
						|
        unsigned arity = curr->get_num_args();
 | 
						|
        for (unsigned i = 0; i < arity; ++i) {
 | 
						|
            if (is_unknown(curr->get_arg(i))) {
 | 
						|
                todo.push_back(curr->get_arg(i));
 | 
						|
            }
 | 
						|
        }
 | 
						|
        if (todo.back() != curr) {
 | 
						|
            continue;
 | 
						|
        }
 | 
						|
        todo.pop_back();
 | 
						|
        if (curr->get_family_id() == m_arith.get_family_id()) {
 | 
						|
            eval_arith(curr);
 | 
						|
        }
 | 
						|
        else if (curr->get_family_id() == m.get_basic_family_id()) {
 | 
						|
            eval_basic(curr);
 | 
						|
        }
 | 
						|
        else {
 | 
						|
            expr_ref vl(m);
 | 
						|
            m_model->eval(curr, vl);
 | 
						|
            assign_value(curr, vl);
 | 
						|
        }
 | 
						|
            
 | 
						|
        IF_VERBOSE(35,verbose_stream() << "assigned "<<mk_pp(curr_e,m) 
 | 
						|
                   <<(is_true(curr_e) ? "true" : is_false(curr_e) ? "false" : "unknown") << "\n";);
 | 
						|
        SASSERT(!is_unknown(curr));
 | 
						|
    }
 | 
						|
        
 | 
						|
    bool has_x = false;
 | 
						|
    for (unsigned i = 0; i < formulas.size(); ++i) {
 | 
						|
        expr * form = formulas[i];
 | 
						|
        SASSERT(!is_unknown(form));
 | 
						|
        TRACE("pdr_verbose", 
 | 
						|
              tout << "formula is " << (is_true(form) ? "true" : is_false(form) ? "false" : "unknown") << "\n" <<mk_pp(form, m)<< "\n";);
 | 
						|
            
 | 
						|
        if (is_false(form)) {
 | 
						|
            IF_VERBOSE(0, verbose_stream() << "formula false in model: " << mk_pp(form, m) << "\n";);
 | 
						|
            UNREACHABLE();
 | 
						|
        }
 | 
						|
        if (is_x(form)) {
 | 
						|
            IF_VERBOSE(0, verbose_stream() << "formula undetermined in model: " << mk_pp(form, m) << "\n";);
 | 
						|
            TRACE("pdr", model_smt2_pp(tout, m, *m_model, 0);); 
 | 
						|
            has_x = true;
 | 
						|
        }
 | 
						|
    }
 | 
						|
    return !has_x;
 | 
						|
}
 | 
						|
 | 
						|
expr_ref model_implicant::eval(model_ref& model, func_decl* d) {
 | 
						|
    SASSERT(d->get_arity() == 0);
 | 
						|
    expr_ref result(m);
 | 
						|
    if (m_array.is_array(d->get_range())) {
 | 
						|
        expr_ref e(m);
 | 
						|
        e = m.mk_const(d);
 | 
						|
        result = eval(model, e);
 | 
						|
    }
 | 
						|
    else {
 | 
						|
        result = model->get_const_interp(d);
 | 
						|
    }
 | 
						|
    return result;
 | 
						|
}
 | 
						|
 | 
						|
expr_ref model_implicant::eval(model_ref& model, expr* e) {
 | 
						|
    expr_ref result(m);
 | 
						|
    m_model = model;
 | 
						|
    VERIFY(m_model->eval(e, result, true));
 | 
						|
    if (m_array.is_array(e)) {
 | 
						|
        vector<expr_ref_vector> stores;
 | 
						|
        expr_ref_vector args(m);
 | 
						|
        expr_ref else_case(m);
 | 
						|
        if (extract_array_func_interp(result, stores, else_case)) {
 | 
						|
            result = m_array.mk_const_array(m.get_sort(e), else_case);
 | 
						|
            while (!stores.empty() && stores.back().back() == else_case) {
 | 
						|
                stores.pop_back();
 | 
						|
            }
 | 
						|
            for (unsigned i = stores.size(); i > 0; ) {
 | 
						|
                --i;
 | 
						|
                args.resize(1);
 | 
						|
                args[0] = result;
 | 
						|
                args.append(stores[i]);
 | 
						|
                result = m_array.mk_store(args.size(), args.c_ptr());
 | 
						|
            }
 | 
						|
            return result;
 | 
						|
        }
 | 
						|
    }
 | 
						|
    return result;
 | 
						|
}
 | 
						|
 | 
						|
 | 
						|
 | 
						|
 |