unknown_address_altered = 1;
if (! CONST_CALL_P (insn)) unknown_address_altered = 1;
prescan_loop (start, end)     rtx start, end;{  register int level = 1;  register rtx insn;  unknown_address_altered = 0;  loop_has_call = 0;  loop_has_volatile = 0;  loop_store_mems_idx = 0;  num_mem_sets = 0;  loops_enclosed = 1;  loop_continue = 0;  for (insn = NEXT_INSN (start); insn != NEXT_INSN (end);       insn = NEXT_INSN (insn))    {      if (GET_CODE (insn) == NOTE)	{	  if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)	    {	      ++level;	      /* Count number of loops contained in this one.  */	      loops_enclosed++;	    }	  else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)	    {	      --level;	      if (level == 0)		{		  end = insn;		  break;		}	    }	  else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)	    {	      if (level == 1)		loop_continue = insn;	    }	}      else if (GET_CODE (insn) == CALL_INSN)	{	  unknown_address_altered = 1;	  loop_has_call = 1;	}      else	{	  if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)	    {	      if (volatile_refs_p (PATTERN (insn)))		loop_has_volatile = 1;	      note_stores (PATTERN (insn), note_addr_stored);	    }	}    }}