message: llvm unit tests have huge arrays/vectors
  bail out on these instead of crashing
diff: @@ -184,7 +184,7 @@ Type* llvm_type2alive(const llvm::Type *ty) {
  auto vty = cast<llvm::VectorType>(ty);
  auto elems = vty->getElementCount().getKnownMinValue();
  auto ety = llvm_type2alive(vty->getElementType());
  - if (!ety)
  + if (!ety || elems > 1024)
  return nullptr;
  cache = make_unique<VectorType>("ty_" + to_string(type_id_counter++),
  elems, *ety);
  @@ -198,7 +198,7 @@ Type* llvm_type2alive(const llvm::Type *ty) {
  auto elemty = aty->getElementType();
  auto elems = aty->getNumElements();
  auto ety = llvm_type2alive(elemty);
  - if (!ety)
  + if (!ety || elems > 100 * 1024)
  return nullptr;
  auto sz_with_padding = DL->getTypeAllocSize(elemty);
  