message: llvm2alive: fix crashes with constant zero aggs
diff: @@ -236,8 +236,8 @@ Value* get_operand(llvm::Value *v) {
  if (auto cnst = dyn_cast<llvm::ConstantAggregateZero>(v)) {
  vector<Value*> vals;
  - for (auto I = cnst->op_begin(), E = cnst->op_end(); I != E; ++I) {
  - vals.emplace_back(get_operand(*I));
  + for (unsigned i = 0, e = cnst->getNumElements(); i != e; ++i) {
  + vals.emplace_back(get_operand(cnst->getElementValue(i)));
  }
  auto val = make_unique<AggregateConst>(*ty, move(vals));
  auto ret = val.get();
  