Re: [ping] Re: Fix PR debug/66728

[Bernd Schmidt <bschmidt@redhat.com>]

On 10/28/2015 02:06 PM, Richard Sandiford wrote:
> Ulrich Weigand <uweigand@de.ibm.com> writes:
>> seems this still hasn't gone upstream ...  Any news?
>
> Ah, sorry, I should have been pinging it.  I think it's still waiting
> for review.

Hmm, unfortunately I have a hard time making sense of this patch. Some 
extra explanation would be appreciated.

>>>   static bool
>>> -add_const_value_attribute (dw_die_ref die, rtx rtl)
>>> +add_const_value_attribute (dw_die_ref die, machine_mode mode, rtx rtl)

Need to document the extra parameter, especially in light of the 
TYPE_MODE/DECL_MODE/rtx mode confusion you pointed out.

>>>   {
>>>     switch (GET_CODE (rtl))
>>>       {
>>>       case CONST_INT:
>>> -      {
>>> -	HOST_WIDE_INT val =3D INTVAL (rtl);
>>> +      if (mode !=3D BLKmode)
>>> +	{
>>> +	  gcc_checking_assert (SCALAR_INT_MODE_P (mode));
>>> +	  HOST_WIDE_INT val =3D INTVAL (rtl);
>>> =20
>>> -	if (val < 0)
>>> -	  add_AT_int (die, DW_AT_const_value, val);
>>> -	else
>>> -	  add_AT_unsigned (die, DW_AT_const_value, (unsigned HOST_WIDE_INT) val);
>>> -      }
>>> -      return true;
>>> +	  if (val < 0)
>>> +	    add_AT_int (die, DW_AT_const_value, val);
>>> +	  else
>>> +	    add_AT_unsigned (die, DW_AT_const_value,
>>> +			     (unsigned HOST_WIDE_INT) val);
>>> +	  return true;
>>> +	}

This is all a bit html mangled, but this and the other change in 
loc_descriptor seem to have the effect of doing nothing when called with 
BLKmode. What is the desired effect of this on the debug information, 
and how is it achieved?


Bernd