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92 lines
2.6 KiB
C++
92 lines
2.6 KiB
C++
/*++
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Copyright (c) 2006 Microsoft Corporation
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Module Name:
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push_app_ite.cpp
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Abstract:
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TODO: Write a better ite lifter
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Author:
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Leonardo de Moura (leonardo) 2008-05-14.
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Revision History:
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--*/
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#include "ast/rewriter/push_app_ite.h"
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#include "ast/ast_pp.h"
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static int has_ite_arg(ast_manager& m, unsigned num_args, expr * const * args) {
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for (unsigned i = 0; i < num_args; i++)
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if (m.is_ite(args[i]))
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return i;
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return -1;
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}
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/**
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\brief Default (conservative) implementation. Return true if there one and only one ite-term argument.
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*/
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bool push_app_ite_cfg::is_target(func_decl * decl, unsigned num_args, expr * const * args) {
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if (m.is_ite(decl))
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return false;
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bool found_ite = false;
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for (unsigned i = 0; i < num_args; i++) {
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if (m.is_ite(args[i]) && !m.is_bool(args[i])) {
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if (found_ite) {
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if (m_conservative)
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return false;
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}
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else {
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found_ite = true;
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}
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}
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}
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CTRACE("push_app_ite", found_ite, tout << "found target for push app ite:\n";
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tout << "conservative " << m_conservative << "\n";
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tout << decl->get_name();
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for (unsigned i = 0; i < num_args; i++) tout << " " << mk_pp(args[i], m);
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tout << "\n";);
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return found_ite;
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}
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br_status push_app_ite_cfg::reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr) {
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if (!is_target(f, num, args)) {
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return BR_FAILED;
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}
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int ite_arg_idx = has_ite_arg(m, num, args);
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if (ite_arg_idx < 0) {
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return BR_FAILED;
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}
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app * ite = to_app(args[ite_arg_idx]);
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expr * c = nullptr, * t = nullptr, * e = nullptr;
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VERIFY(m.is_ite(ite, c, t, e));
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expr ** args_prime = const_cast<expr**>(args);
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expr * old = args_prime[ite_arg_idx];
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args_prime[ite_arg_idx] = t;
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expr_ref t_new(m.mk_app(f, num, args_prime), m);
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args_prime[ite_arg_idx] = e;
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expr_ref e_new(m.mk_app(f, num, args_prime), m);
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args_prime[ite_arg_idx] = old;
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result = m.mk_ite(c, t_new, e_new);
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TRACE("push_app_ite", tout << result << "\n";);
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if (m.proofs_enabled()) {
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result_pr = m.mk_rewrite(m.mk_app(f, num, args), result);
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}
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return BR_REWRITE2;
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}
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bool ng_push_app_ite_cfg::is_target(func_decl * decl, unsigned num_args, expr * const * args) {
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bool r = push_app_ite_cfg::is_target(decl, num_args, args);
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if (!r)
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return false;
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for (unsigned i = 0; i < num_args; i++)
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if (!is_ground(args[i]))
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return true;
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return false;
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}
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