event./univ. and syntactic implications rewriting in ltl_simplifier.
* src/ltlvisit/reduce.cc (reduce_visitor): Move ... * src/ltlvisit/simplify.cc (simplify_visitor): ... here, and adjust to use the new ltl_simplifier_options. * src/ltlvisit/reduce.cc (reduce): Use ltl_simplifier to perform the work of reduce_visitor. Eventually we want to get rid of reduce.cc. * src/ltlvisit/reduce.hh (reduce): Remove the syntactic_implication_cache used as third argument.
This commit is contained in:
Alexandre Duret-Lutz
parent
503bdb5bbf
commit
dd1cd89a73
3 changed files with 423 additions and 415 deletions
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@ -23,7 +23,6 @@
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#include "reduce.hh"
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#include "basicreduce.hh"
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#include "syntimpl.hh"
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#include "ltlast/allnodes.hh"
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#include <cassert>
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@ -31,403 +30,27 @@
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#include "simpfg.hh"
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#include "nenoform.hh"
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#include "contain.hh"
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#include "simplify.hh"
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namespace spot
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{
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namespace ltl
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{
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namespace
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{
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/////////////////////////////////////////////////////////////////////////
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class reduce_visitor: public visitor
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{
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public:
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reduce_visitor(int opt, syntactic_implication_cache* c)
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: opt_(opt), c_(c)
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{
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}
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virtual ~reduce_visitor()
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{
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}
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formula*
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result() const
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{
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return result_;
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}
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void
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visit(atomic_prop* ap)
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{
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formula* f = ap->clone();
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result_ = f;
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}
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void
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visit(constant* c)
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{
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result_ = c;
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}
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void
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visit(bunop* bo)
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{
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result_ = bunop::instance(bo->op(), recurse(bo->child()),
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bo->min(), bo->max());
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}
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void
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visit(unop* uo)
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{
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result_ = recurse(uo->child());
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switch (uo->op())
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{
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case unop::F:
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/* If f is a pure eventuality formula then F(f)=f. */
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if (!(opt_ & Reduce_Eventuality_And_Universality)
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|| !result_->is_eventual())
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result_ = unop::instance(unop::F, result_);
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return;
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case unop::G:
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/* If f is a pure universality formula then G(f)=f. */
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if (!(opt_ & Reduce_Eventuality_And_Universality)
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|| !result_->is_universal())
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result_ = unop::instance(unop::G, result_);
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return;
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case unop::Not:
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case unop::X:
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case unop::Finish:
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case unop::Closure:
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case unop::NegClosure:
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result_ = unop::instance(uo->op(), result_);
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return;
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}
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/* Unreachable code. */
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assert(0);
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}
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void
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visit(binop* bo)
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{
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binop::type op = bo->op();
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formula* f2 = recurse(bo->second());
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if (opt_ & Reduce_Eventuality_And_Universality)
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{
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/* If b is a pure eventuality formula then a U b = b.
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If b is a pure universality formula a R b = b. */
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if ((f2->is_eventual() && (op == binop::U))
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|| (f2->is_universal() && (op == binop::R)))
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{
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result_ = f2;
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return;
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}
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}
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formula* f1 = recurse(bo->first());
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if (opt_ & Reduce_Eventuality_And_Universality)
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{
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/* If a is a pure eventuality formula then a M b = a & b.
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If a is a pure universality formula a W b = a|b. */
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if (f1->is_eventual() && (op == binop::M))
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{
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result_ = multop::instance(multop::And, f1, f2);
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return;
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}
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if (f1->is_universal() && (op == binop::W))
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{
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result_ = multop::instance(multop::Or, f1, f2);
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return;
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}
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}
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/* case of implies */
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if (opt_ & Reduce_Syntactic_Implications)
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{
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switch (op)
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{
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case binop::Xor:
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case binop::Equiv:
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case binop::Implies:
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assert(!"operator not supported for syntactic implication");
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return;
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case binop::UConcat:
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case binop::EConcat:
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case binop::EConcatMarked:
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break;
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case binop::U:
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/* a < b => a U b = b */
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if (c_->syntactic_implication(f1, f2))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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/* !b < a => a U b = Fb */
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if (c_->syntactic_implication_neg(f2, f1, false))
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{
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result_ = unop::instance(unop::F, f2);
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f1->destroy();
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return;
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}
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/* a < b => a U (b U c) = (b U c) */
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/* a < b => a U (b W c) = (b W c) */
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if (f2->kind() == formula::BinOp)
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{
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binop* bo = static_cast<binop*>(f2);
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if ((bo->op() == binop::U || bo->op() == binop::W)
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&& c_->syntactic_implication(f1, bo->first()))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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}
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break;
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case binop::R:
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/* b < a => a R b = b */
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if (c_->syntactic_implication(f2, f1))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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/* b < !a => a R b = Gb */
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if (c_->syntactic_implication_neg(f2, f1, true))
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{
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result_ = unop::instance(unop::G, f2);
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f1->destroy();
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return;
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}
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if (f2->kind() == formula::BinOp)
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{
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/* b < a => a R (b R c) = b R c */
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/* b < a => a R (b M c) = b M c */
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binop* bo = static_cast<binop*>(f2);
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if ((bo->op() == binop::R || bo->op() == binop::M)
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&& c_->syntactic_implication(bo->first(), f1))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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/* a < b => a R (b R c) = a R c */
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if (bo->op() == binop::R
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&& c_->syntactic_implication(f1, bo->first()))
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{
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result_ = binop::instance(binop::R, f1,
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bo->second()->clone());
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f2->destroy();
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return;
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}
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}
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break;
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case binop::W:
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/* a < b => a W b = b */
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if (c_->syntactic_implication(f1, f2))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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/* !b < a => a W b = 1 */
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if (c_->syntactic_implication_neg(f2, f1, false))
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{
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result_ = constant::true_instance();
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f1->destroy();
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f2->destroy();
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return;
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}
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/* a < b => a W (b W c) = (b W c) */
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if (f2->kind() == formula::BinOp)
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{
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binop* bo = static_cast<binop*>(f2);
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if (bo->op() == binop::W
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&& c_->syntactic_implication(f1, bo->first()))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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}
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break;
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case binop::M:
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/* b < a => a M b = b */
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if (c_->syntactic_implication(f2, f1))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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/* b < !a => a M b = 0 */
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if (c_->syntactic_implication_neg(f2, f1, true))
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{
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result_ = constant::false_instance();
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f1->destroy();
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f2->destroy();
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return;
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}
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if (f2->kind() == formula::BinOp)
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{
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/* b < a => a M (b M c) = b M c */
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binop* bo = static_cast<binop*>(f2);
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if (bo->op() == binop::M
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&& c_->syntactic_implication(bo->first(), f1))
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{
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result_ = f2;
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f1->destroy();
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return;
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}
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/* a < b => a M (b M c) = a M c */
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/* a < b => a M (b R c) = a M c */
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if ((bo->op() == binop::M || bo->op() == binop::R)
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&& c_->syntactic_implication(f1, bo->first()))
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{
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result_ = binop::instance(binop::M, f1,
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bo->second()->clone());
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f2->destroy();
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return;
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}
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}
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break;
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}
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}
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result_ = binop::instance(op, f1, f2);
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}
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void
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visit(automatop*)
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{
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assert(0);
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}
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void
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visit(multop* mo)
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{
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unsigned mos = mo->size();
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multop::vec* res = new multop::vec;
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for (unsigned i = 0; i < mos; ++i)
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res->push_back(recurse(mo->nth(i)));
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if ((opt_ & Reduce_Syntactic_Implications)
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&& (mo->op() != multop::Concat)
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&& (mo->op() != multop::Fusion))
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{
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bool removed = true;
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multop::vec::iterator f1;
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multop::vec::iterator f2;
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while (removed)
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{
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removed = false;
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f2 = f1 = res->begin();
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++f1;
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while (f1 != res->end())
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{
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assert(f1 != f2);
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// a < b => a + b = b
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// a < b => a & b = a
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if ((c_->syntactic_implication(*f1, *f2) && // f1 < f2
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(mo->op() == multop::Or)) ||
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((c_->syntactic_implication(*f2, *f1)) && // f2 < f1
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(mo->op() == multop::And)))
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{
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// We keep f2
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(*f1)->destroy();
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res->erase(f1);
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removed = true;
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break;
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}
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else if ((c_->syntactic_implication(*f2, *f1) // f2 < f1
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&& (mo->op() == multop::Or)) ||
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((c_->syntactic_implication(*f1, *f2)) // f1 < f2
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&& (mo->op() == multop::And)))
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{
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// We keep f1
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(*f2)->destroy();
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res->erase(f2);
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removed = true;
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break;
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}
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else
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++f1;
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}
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}
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// We cannot run syntactic_implication_neg on SERE
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// formulae, unless they are just Boolean formulae.
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if (mo->is_boolean() || !mo->is_sere_formula())
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{
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bool is_and = mo->op() != multop::Or;
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/* f1 < !f2 => f1 & f2 = false
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!f1 < f2 => f1 | f2 = true */
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for (f1 = res->begin(); f1 != res->end(); f1++)
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for (f2 = res->begin(); f2 != res->end(); f2++)
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if (f1 != f2 &&
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c_->syntactic_implication_neg(*f1, *f2, is_and))
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{
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for (multop::vec::iterator j = res->begin();
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j != res->end(); j++)
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(*j)->destroy();
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res->clear();
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delete res;
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if (is_and)
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result_ = constant::false_instance();
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else
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result_ = constant::true_instance();
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return;
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}
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}
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}
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if (!res->empty())
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{
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result_ = multop::instance(mo->op(), res);
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return;
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}
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assert(0);
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}
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formula*
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recurse(formula* f)
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{
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return reduce(f, opt_, c_);
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}
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protected:
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formula* result_;
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int opt_;
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syntactic_implication_cache* c_;
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};
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} // anonymous
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formula*
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reduce(const formula* f, int opt, syntactic_implication_cache* c)
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reduce(const formula* f, int opt)
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{
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formula* f1;
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formula* f2;
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formula* prev = 0;
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syntactic_implication_cache* sic =
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c ? c : new syntactic_implication_cache;
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ltl_simplifier_options o;
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o.reduce_basics = opt & Reduce_Basics;
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o.synt_impl = opt & Reduce_Syntactic_Implications;
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o.event_univ = opt & Reduce_Eventuality_And_Universality;
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o.containment_checks = opt & Reduce_Containment_Checks;
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o.containment_checks_stronger = opt & Reduce_Containment_Checks_Stronger;
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ltl_simplifier simplifier(o);
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int n = 0;
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@ -458,16 +81,9 @@ namespace spot
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f2 = f1;
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}
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if (opt & (Reduce_Syntactic_Implications
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| Reduce_Eventuality_And_Universality))
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{
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reduce_visitor v(opt, sic);
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f2->accept(v);
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f1 = v.result();
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f2->destroy();
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f2 = f1;
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}
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f1 = simplifier.simplify(f2);
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f2->destroy();
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f2 = f1;
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if (opt & (Reduce_Containment_Checks
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| Reduce_Containment_Checks_Stronger))
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@ -482,9 +98,6 @@ namespace spot
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}
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prev->destroy();
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if (c == 0)
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delete sic;
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return const_cast<formula*>(f);
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}
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