Re: how can I write a right V32QI Unpack Low Data insn pattern?

[Dave Korn <dave dot korn dot cygwin at gmail dot com>]

On 02/03/2011 07:56, Liu wrote:

> The wrong code is :
>  L9284: ATTRIBUTE_UNUSED_LABEL
>   x3 = XEXP (x2, {);
>   if (x3 == const_int_rtx[MAX_SAVED_CONST_INT + (13)])
>     goto L9285;
>   goto ret0;
> 
>  L9285: ATTRIBUTE_UNUSED_LABEL
>   x3 = XEXP (x2, |);
>   if (x3 == const_int_rtx[MAX_SAVED_CONST_INT + (45)])
>     goto L9286;
>   goto ret0;
> 
>  L9286: ATTRIBUTE_UNUSED_LABEL
>   x3 = XEXP (x2, });
>   if (x3 == const_int_rtx[MAX_SAVED_CONST_INT + (14)])
>     goto L9287;
>   goto ret0;
> 
>  L9287: ATTRIBUTE_UNUSED_LABEL
>   x3 = XEXP (x2, ~);
>   if (x3 == const_int_rtx[MAX_SAVED_CONST_INT + (46)])
>     goto L9288;
>   goto ret0;

  Well, that's coming from here:

      else
	printf ("%sx%d = XEXP (x%d, %c);\n",
		indent, depth + 1, depth, newpos[depth]);
      ++depth;

at the end of genrecog.c#change_state().  The problematic position string is
presumably being generated here:

	if (was_code == MATCH_OPERATOR || was_code == MATCH_PARALLEL)
	  {
	    char base = (was_code == MATCH_OPERATOR ? '0' : 'a');
	    for (i = 0; i < (size_t) XVECLEN (pattern, 2); i++)
	      {
		subpos[depth] = i + base;
		sub = add_to_sequence (XVECEXP (pattern, 2, i),
				       &sub->success, subpos, insn_type, 0);
	      }
	  }

in the MATCH_OPERAND case of the big switch in add_to_sequence().  Possibly
change_state needs to do something like

	printf ("%sx%d = XEXP (x%d, %d);\n",
		indent, depth + 1, depth,
		newpos[depth] > 'a'
		  ? newpos[depth] - 'a'
		  : newpos[depth] - '0');

... but you need someone who understands genrecog and how the position string
representations are supposed to work to advise you here, and that's not me I'm
afraid.

    cheers,
      DaveK