I believe that I have found a minor bug in the framesize calculation in chaitin.cpp:
 
  // Convert that to a frame_slot number.
  if( _max_reg <= _matcher._new_SP )
    _framesize = C->out_preserve_stack_slots();
  else _framesize = _max_reg -_matcher._new_SP;
  assert((int)(_matcher._new_SP+_framesize) >= (int)_matcher._out_arg_limit, "framesize must be large enough");
 
  // This frame must preserve the required fp alignment
  const int stack_alignment_in_words = Matcher::stack_alignment_in_slots();
  if (stack_alignment_in_words > 0)
    _framesize = round_to(_framesize, Matcher::stack_alignment_in_bytes());
  assert( _framesize >= 0 && _framesize <= 1000000, "sanity check" );
 
The granularity of _framesize at this point is OptoReg slots and so should it be aligned to Matcher::stack_alignment_in_slots() instead of Matcher::stack_alignment_in_bytes()? This is causing the minimum framesize on Itanium to be 80 bytes instead of 32 (2 words scratch, 1 word for the original_pc offset, and 1 word for alignment).