Esempio n. 1
0
Theorem CNF_Manager::replaceITErec(const Expr& e, Var v, bool translateOnly)
{
  // Quick exit for atomic expressions
  if (e.isAtomic()) return d_commonRules->reflexivityRule(e);

  // Check cache
  Theorem thm;
  bool foundInCache = false;
  ExprHashMap<Theorem>::iterator iMap = d_iteMap.find(e);
  if (iMap != d_iteMap.end()) {
    thm = (*iMap).second;
    foundInCache = true;
  }

  if (e.getKind() == ITE) {
    // Replace non-Bool ITE expressions
    DebugAssert(!e.getType().isBool(), "Expected non-Bool ITE");
    // generate e = x for new x
    if (!foundInCache) thm = d_commonRules->varIntroSkolem(e);
    Theorem thm2 = d_commonRules->symmetryRule(thm);
    thm2 = d_commonRules->iffMP(thm2, d_rules->ifLiftRule(thm2.getExpr(), 1));
    d_translateQueueVars.push_back(v);
    d_translateQueueThms.push_back(thm2);
    d_translateQueueFlags.push_back(translateOnly);
  }
  else {
    // Recursively traverse, replacing ITE's
    vector<Theorem> thms;
    vector<unsigned> changed;
    unsigned index = 0;
    Expr::iterator i, iend;
    if (foundInCache) {
      for(i = e.begin(), iend = e.end(); i!=iend; ++i, ++index) {
        replaceITErec(*i, v, translateOnly);
      }
    }
    else {
      for(i = e.begin(), iend = e.end(); i!=iend; ++i, ++index) {
        thm = replaceITErec(*i, v, translateOnly);
        if (!thm.isRefl()) {
          thms.push_back(thm);
          changed.push_back(index);
        }
      }
      if(changed.size() > 0) {
        thm = d_commonRules->substitutivityRule(e, changed, thms);
      }
      else thm = d_commonRules->reflexivityRule(e);
    }
  }

  // Update cache and return
  if (!foundInCache) d_iteMap[e] = thm;
  return thm;
}
Esempio n. 2
0
bool TheoryArith::leavesAreNumConst(const Expr& e)
{
  DebugAssert(e.isTerm() ||
              (e.isPropAtom() && theoryOf(e) == this),
              "Expected term or arith prop atom");

  if (e.validTerminalsConstFlag()) {
    return e.getTerminalsConstFlag();
  }

  if (e.isRational()) {
    e.setTerminalsConstFlag(true);
    return true;
  }

  if (e.isAtomic() && isLeaf(e)) {
    e.setTerminalsConstFlag(false);
    return false;
  }

  DebugAssert(e.arity() > 0, "Expected non-zero arity");
  int k = 0;

  if (e.isITE()) {
    k = 1;
  }

  for (; k < e.arity(); ++k) {
    if (!leavesAreNumConst(e[k])) {
      e.setTerminalsConstFlag(false);
      return false;
    }
  }
  e.setTerminalsConstFlag(true);
  return true;
}