This clears only up to sig->count() slots

https://github.com/openjdk/jdk/blob/902aa4dcd297fef34cb302e468b030c48665ec84/src/hotspot/share/ci/bcEscapeAnalyzer.cpp#L1266-L1279

void BCEscapeAnalyzer::clear_escape_info() {
  ciSignature* sig = method()->signature();
  int arg_count = sig->count();
  ArgumentMap var;
  if (!method()->is_static()) {
    arg_count++; // allow for "this"
  }
  for (int i = 0; i < arg_count; i++) {
    set_arg_modified(i, OFFSET_ANY, 4);
    var.clear();
    var.set(i);
    set_modified(var, OFFSET_ANY, 4);
    set_global_escape(var);
  }

However, the number of slots in _arg_modified is method->arg_size(), which includes a slot for "this", and has one extra slot for each long/double arguments:

https://github.com/openjdk/jdk/blob/902aa4dcd297fef34cb302e468b030c48665ec84/src/hotspot/share/ci/bcEscapeAnalyzer.cpp#L1444-L1460

BCEscapeAnalyzer::BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent)
[...]
    , _arg_size(method ? method->arg_size() : 0)
[...]
    _arg_modified = (uint *) arena->Amalloc(_arg_size * sizeof(uint));