The StackValue API treats all primitive values as intptr_t which means users of the API need to do a bunch of ugly casting when getting/setting primitive j<type> values from/to a StackValue:

jint StackValueCollection::int_at(int slot) const {
  intptr_t val = at(slot)->get_int();
  jint ival = *((jint*) (&val));
  return ival;
}

void StackValueCollection::set_int_at(int slot, jint value) {
  intptr_t val;
  *((jint*) (&val)) = value;
  at(slot)->set_int(val);
}

More examples:
https://github.com/openjdk/jdk/blob/6bab0f539fba8fb441697846347597b4a0ade428/src/hotspot/share/runtime/deoptimization.cpp#L905
https://github.com/openjdk/jdk/blob/6bab0f539fba8fb441697846347597b4a0ade428/src/hotspot/share/runtime/deoptimization.cpp#L897

This casting to/from intptr_t could be behind the StackValue API and instead there would be `j<type> get_j<type>()` and `void set_j<type>(j<type> value)` methods instread of the raw `intptr_t get_int` and `void set_int(intptr_t value)` methods.