Method preprocess

tools/transform.cpp:1729–1962

}

void Transform::preprocess() {
  if (config::tgt_is_asm) {
    tgt.getFnAttrs().set(FnAttrs::Asm);

    // there are no #side-effect things in assembly
    vector<Instr*> to_remove;
    for (auto &bb : src.getBBs()) {
      for (auto &i : bb->instrs()) {
        if (auto *call = dynamic_cast<const FnCall*>(&i)) {
          if (call->getFnName() == "#sideeffect") {
            to_remove.emplace_back(const_cast<Instr*>(&i));
          }
        }
      }
      for (auto &i : to_remove) {
        bb->delInstr(i);
      }
      to_remove.clear();
    }
  }

  remove_unreachable_bbs(src);
  remove_unreachable_bbs(tgt);

  // remove store of initializers to global variables that aren't needed to
  // verify the transformation
  // We only remove inits if it's possible to remove from both programs to keep
  // memories syntactically equal
  auto remove_init_tgt = can_remove_init(tgt);
  for (auto &[name, isrc] : can_remove_init(src)) {
    auto Itgt = remove_init_tgt.find(name);
    if (Itgt == remove_init_tgt.end())
      continue;
    src.getFirstBB().delInstr(isrc);
    tgt.getFirstBB().delInstr(Itgt->second);
    // TODO: check that tgt init refines that of src
  }

  // remove constants introduced in target
  auto src_gvs = src.getGlobalVarNames();
  for (auto &[name, itgt] : remove_init_tgt) {
    if (find(src_gvs.begin(), src_gvs.end(), name.substr(1)) == src_gvs.end())
      tgt.getFirstBB().delInstr(itgt);
  }

  // optimize pointer comparisons
  optimize_ptrcmp(src);
  optimize_ptrcmp(tgt);

  // remove side-effect free instructions without users
  vector<Instr*> to_remove;
  for (auto fn : { &src, &tgt }) {
    bool changed;
    do {
      auto users = fn->getUsers();
      changed = false;

      for (auto bb : fn->getBBs()) {