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105 lines
3 KiB
C++
105 lines
3 KiB
C++
/*++
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Copyright (c) 2022 Microsoft Corporation
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Module Name:
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distribute_forall.cpp
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Author:
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Leonardo de Moura (leonardo) 2012-02-18.
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Nikolaj Bjorner (nbjorner) 2022-11-24
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--*/
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#include "ast/ast_util.h"
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#include "ast/rewriter/rewriter.h"
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#include "ast/rewriter/rewriter_def.h"
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#include "ast/rewriter/var_subst.h"
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#include "ast/simplifiers/dependent_expr_state.h"
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#include "ast/simplifiers/distribute_forall.h"
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struct distribute_forall_simplifier::rw_cfg : public default_rewriter_cfg {
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ast_manager & m;
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rw_cfg(ast_manager & m):m(m) {}
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bool reduce_quantifier(quantifier * old_q,
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expr * new_body,
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expr * const * new_patterns,
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expr * const * new_no_patterns,
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expr_ref & result,
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proof_ref & result_pr) {
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quantifier_ref tmp_q(m);
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expr_ref_vector es(m);
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expr* f;
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if (is_forall(old_q)) {
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// (forall X (and F1 ... Fn))
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// -->
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// (and (forall X F1)
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// ...
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// (forall X Fn)
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if (!m.is_and(new_body) && !(m.is_not(new_body, f) && (m.is_implies(f) || m.is_or(f))))
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return false;
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flatten_and(new_body, es);
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unsigned i = 0;
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for (expr* arg : es) {
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tmp_q = m.update_quantifier(old_q, arg);
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es[i++] = elim_unused_vars(m, tmp_q, params_ref());
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}
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result = mk_and(es);
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if (m.proofs_enabled())
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result_pr = m.mk_push_quant(old_q, result);
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return true;
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}
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if (is_exists(old_q)) {
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// (exists X (or F1 ... Fn))
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// -->
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// (or (exists X F1)
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// ...
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// (exists X Fn)
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if (!m.is_or(new_body) && !m.is_implies(new_body) && !(m.is_not(new_body, f) && m.is_and(f)))
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return false;
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flatten_or(new_body, es);
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unsigned i = 0;
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for (expr* arg : es) {
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tmp_q = m.update_quantifier(old_q, arg);
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es[i++] = elim_unused_vars(m, tmp_q, params_ref());
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}
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result = mk_or(es);
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if (m.proofs_enabled())
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result_pr = m.mk_push_quant(old_q, result);
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return true;
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}
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return false;
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}
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};
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struct distribute_forall_simplifier::rw : public rewriter_tpl<rw_cfg> {
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rw_cfg m_cfg;
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rw(ast_manager & m, bool proofs_enabled):
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rewriter_tpl<rw_cfg>(m, proofs_enabled, m_cfg),
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m_cfg(m) {
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}
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};
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void distribute_forall_simplifier::reduce() {
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if (!m_fmls.has_quantifiers())
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return;
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rw rw(m, m.proofs_enabled());
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expr_ref r(m);
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proof_ref pr(m);
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for (unsigned idx : indices()) {
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auto const& d = m_fmls[idx];
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if (!has_quantifiers(d.fml()))
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continue;
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rw(d.fml(), r, pr);
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if (r != d.fml())
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m_fmls.update(idx, dependent_expr(m, r, mp(d.pr(), pr), d.dep()));
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}
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};
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