Re: [PATCH] FOR_EACH_RTX construct to replace for_each_rtx

[Richard Henderson <rth at redhat dot com>]

On Wed, Jan 19, 2005 at 06:32:32PM +0100, Paolo Bonzini wrote:
> - static rtx *btr_reference_found;
> - 
> - /* A subroutine of btr_referenced_p, called through for_each_rtx.
> -    PREG is a pointer to an rtx that is to be excluded from the
> -    traversal.  If we find a reference to a target register anywhere
> -    else, return 1, and put a pointer to it into btr_reference_found.  */
> - static int
> - find_btr_reference (rtx *px, void *preg)
> - {
> -   rtx x;
> -   int regno, i;
> - 
> -   if (px == preg)
> -     return -1;
> -   x = *px;
> -   if (!REG_P (x))
> -     return 0;
> -   regno = REGNO (x);
> -   for (i = hard_regno_nregs[regno][GET_MODE (x)] - 1; i >= 0; i--)
> -     if (TEST_HARD_REG_BIT (all_btrs, regno+i))
> -       {
> - 	btr_reference_found = px;
> - 	return 1;
> -       }
> -   return -1;
> - }
> - 
> - /* Return nonzero if X references (sets or reads) any branch target register.
> -    If EXCLUDEP is set, disregard any references within the rtx pointed to
> -    by it.  If returning nonzero, also set btr_reference_found as above.  */
> - static int
> - btr_referenced_p (rtx x, rtx *excludep)
> - {
> -   return for_each_rtx (&x, find_btr_reference, excludep);
> - }
...
> ! /* Find and return a use of a target register within an instruction INSN.
> !    If EXCLUDEP is set, disregard any references within the rtx pointed to
> !    by it.  */
>   static rtx *
> ! find_btr_use (rtx insn, rtx *excludep)
>   {
> !   rtx_iter iter;
> !   rtx *loc;
> !   FOR_EACH_RTX (&insn, loc, iter)
> !     {
> !       rtx x;
> !       int regno, i;
> ! 
> !       if (loc == excludep)
> !         {
> ! 	  rtx_iter_skip (&iter);
> ! 	  continue;
> ! 	}
> ! 
> !       x = *loc;
> !       if (!REG_P (x))
> !         continue;
> !       regno = REGNO (x);
> !       for (i = hard_regno_nregs[regno][GET_MODE (x)] - 1; i >= 0; i--)
> !         if (TEST_HARD_REG_BIT (all_btrs, regno+i))
> !           return loc;
> !     }
> ! 
> !   return NULL;
>   }


I don't like the fact that this isn't an exact drop-in replacement
of FOR_EACH_RTX.  I very much feel that the first version of this
change to be installed should support *exactly* the same interface.

Nor should you have done any simultaneous renamings of functions.


r~