Thanks for doing this.
Kenneth Zadeck <zad...@naturalbridge.com> writes:
> @@ -1204,11 +1204,11 @@ wide_int_to_tree (tree type, const wide_
> }
>
> wide_int cst = wide_int::from (pcst, prec, sgn);
> - int len = int (cst.get_len ());
> - int small_prec = prec & (HOST_BITS_PER_WIDE_INT - 1);
> + unsigned int len = int (cst.get_len ());
The cast to int is redundant now (get_len () is unsigned int).
> @@ -5172,39 +5173,48 @@ wi::int_traits <const_tree>::get_precisi
> return TYPE_PRECISION (TREE_TYPE (tcst));
> }
>
> -/* Convert the tree_cst X into a wide_int. */
> +/* Convert the tree_cst X into a wide_int of PRECISION. */
> inline wi::storage_ref
> wi::int_traits <const_tree>::decompose (HOST_WIDE_INT *scratch,
> unsigned int precision, const_tree x)
> {
> - unsigned int xprecision = get_precision (x);
> unsigned int len = TREE_INT_CST_NUNITS (x);
> const HOST_WIDE_INT *val = (const HOST_WIDE_INT *) &TREE_INT_CST_ELT (x,
> 0);
> unsigned int max_len = ((precision + HOST_BITS_PER_WIDE_INT - 1)
> / HOST_BITS_PER_WIDE_INT);
> - /* Truncate the constant if necessary. */
> - if (len > max_len)
> - return wi::storage_ref (val, max_len, precision);
> + unsigned int xprecision = get_precision (x);
> +
> + gcc_assert (precision >= xprecision);
>
> - if (precision <= xprecision)
> + /* Got to be careful of precision 0 values. */
> + if (precision)
> + len = MIN (len, max_len);
> + if (TYPE_SIGN (TREE_TYPE (x)) == UNSIGNED)
> {
> - if (precision < HOST_BITS_PER_WIDE_INT
> - && TYPE_SIGN (TREE_TYPE (x)) == UNSIGNED)
> + unsigned int small_prec = precision & (HOST_BITS_PER_WIDE_INT - 1);
> + if (small_prec)
> + {
> + /* We have to futz with this because the canonization for
> + short unsigned numbers in wide-int is different from the
> + canonized short unsigned numbers in the tree-cst. */
> + if (len == max_len)
> + {
> + for (unsigned int i = 0; i < len - 1; i++)
> + scratch[i] = val[i];
> + scratch[len - 1] = sext_hwi (val[len - 1], precision);
> + return wi::storage_ref (scratch, len, precision);
> + }
> + }
> +
> + if (precision < xprecision + HOST_BITS_PER_WIDE_INT)
> {
> - /* The rep of wide-int is signed, so if the value comes from
> - an unsigned int_cst, we have to sign extend it to make it
> - correct. */
> - scratch[0] = sext_hwi (val[0], precision);
> - return wi::storage_ref (scratch, 1, precision);
> + len = wi::force_to_size (scratch, val, len, xprecision, precision,
> UNSIGNED);
> + return wi::storage_ref (scratch, len, precision);
> }
AFAICT, with the assert, this last case is only needed when
!small_prec && precision == xprecision, and the only situation it
handles is where the top bit is set. Is that right? If so,
we can use the original val as-is and just trim the length. I.e.
if (small_prec)
;
else if (precision == xprecision)
while (len >= 0 && val[len - 1] == -1)
len--;
Sorry if I've got that wrong -- it's taking a while to page the
wide-int stuff back in.
Thanks,
Richard
