On Tue, 17 Oct 2023, Jakub Jelinek wrote:
> Hi!
>
> The following patch implements printing of wide_int/widest_int numbers
> decimally when asked for that using print_dec{,s,u}, even if they have
> precision larger than 64 and get_len () above 1 (right now we printed
> them hexadecimally and even negative numbers as huge positive hexadecimal).
>
> In order to avoid the expensive division/modulo by 10^19 twice, once to
> estimate how many will be needed and another to actually print it, the
> patch prints the 19 digit chunks in reverse order (from least significant
> to most significant) and then reorders those with linear complexity to form
> the right printed number.
> Tested with printing both 256 and 320 bit numbers (first as an example
> of even number of 19 digit chunks plus one shorter above it, the second
> as an example of odd number of 19 digit chunks plus one shorter above it).
>
> The l * HOST_BITS_PER_WIDE_INT / 3 + 3 estimatition thinking about it now
> is one byte too much (one byte for -, one for '\0') and too conservative,
> so we could go with l * HOST_BITS_PER_WIDE_INT / 3 + 2 as well, or e.g.
> l * HOST_BITS_PER_WIDE_INT * 10 / 33 + 3 as even less conservative
> estimation (though more expensive to compute in inline code).
> But that l * HOST_BITS_PER_WIDE_INT / 4 + 4; is likely one byte too much
> as well, 2 bytes for 0x, one byte for '\0' and where does the 4th one come
> from? Of course all of these assuming HOST_BITS_PER_WIDE_INT is a multiple
> of 64...
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Thanks,
Richard.
> 2023-10-17 Jakub Jelinek <ja...@redhat.com>
>
> * wide-int-print.h (print_dec_buf_size): For length, divide number
> of bits by 3 and add 3 instead of division by 4 and adding 4.
> * wide-int-print.cc (print_decs): Remove superfluous ()s. Don't call
> print_hex, instead call print_decu on either negated value after
> printing - or on wi itself.
> (print_decu): Don't call print_hex, instead print even large numbers
> decimally.
> (pp_wide_int_large): Assume len from print_dec_buf_size is big enough
> even if it returns false.
> * pretty-print.h (pp_wide_int): Use print_dec_buf_size to check if
> pp_wide_int_large should be used.
> * tree-pretty-print.cc (dump_generic_node): Use print_hex_buf_size
> to compute needed buffer size.
>
> --- gcc/wide-int-print.h.jj 2023-10-15 23:04:06.195422820 +0200
> +++ gcc/wide-int-print.h 2023-10-16 10:14:41.327401697 +0200
> @@ -42,7 +42,7 @@ print_dec_buf_size (const wide_int_ref &
> unsigned int l = wi.get_len ();
> if ((l != 1 || sgn == UNSIGNED) && wi::neg_p (wi))
> l = WIDE_INT_MAX_HWIS (wi.get_precision ());
> - l = l * HOST_BITS_PER_WIDE_INT / 4 + 4;
> + l = l * HOST_BITS_PER_WIDE_INT / 3 + 3;
> *len = l;
> return UNLIKELY (l > WIDE_INT_PRINT_BUFFER_SIZE);
> }
> --- gcc/wide-int-print.cc.jj 2023-10-15 23:04:06.195422820 +0200
> +++ gcc/wide-int-print.cc 2023-10-16 11:20:30.662174735 +0200
> @@ -49,14 +49,12 @@ print_dec (const wide_int_ref &wi, FILE
> }
>
>
> -/* Try to print the signed self in decimal to BUF if the number fits
> - in a HWI. Other print in hex. */
> +/* Try to print the signed self in decimal to BUF. */
>
> void
> print_decs (const wide_int_ref &wi, char *buf)
> {
> - if ((wi.get_precision () <= HOST_BITS_PER_WIDE_INT)
> - || (wi.get_len () == 1))
> + if (wi.get_precision () <= HOST_BITS_PER_WIDE_INT || wi.get_len () == 1)
> {
> if (wi::neg_p (wi))
> sprintf (buf, "-" HOST_WIDE_INT_PRINT_UNSIGNED,
> @@ -64,12 +62,17 @@ print_decs (const wide_int_ref &wi, char
> else
> sprintf (buf, HOST_WIDE_INT_PRINT_DEC, wi.to_shwi ());
> }
> + else if (wi::neg_p (wi))
> + {
> + widest2_int w = widest2_int::from (wi, SIGNED);
> + *buf = '-';
> + print_decu (-w, buf + 1);
> + }
> else
> - print_hex (wi, buf);
> + print_decu (wi, buf);
> }
>
> -/* Try to print the signed self in decimal to FILE if the number fits
> - in a HWI. Other print in hex. */
> +/* Try to print the signed self in decimal to FILE. */
>
> void
> print_decs (const wide_int_ref &wi, FILE *file)
> @@ -82,8 +85,7 @@ print_decs (const wide_int_ref &wi, FILE
> fputs (p, file);
> }
>
> -/* Try to print the unsigned self in decimal to BUF if the number fits
> - in a HWI. Other print in hex. */
> +/* Try to print the unsigned self in decimal to BUF. */
>
> void
> print_decu (const wide_int_ref &wi, char *buf)
> @@ -92,11 +94,37 @@ print_decu (const wide_int_ref &wi, char
> || (wi.get_len () == 1 && !wi::neg_p (wi)))
> sprintf (buf, HOST_WIDE_INT_PRINT_UNSIGNED, wi.to_uhwi ());
> else
> - print_hex (wi, buf);
> + {
> + widest2_int w = widest2_int::from (wi, UNSIGNED), r;
> + widest2_int ten19 = HOST_WIDE_INT_UC (10000000000000000000);
> + char buf2[20], next1[19], next2[19];
> + size_t l, c = 0, i;
> + /* In order to avoid dividing this twice, print the 19 decimal
> + digit chunks in reverse order into buffer and then reorder
> + them in-place. */
> + while (wi::gtu_p (w, ten19))
> + {
> + w = wi::divmod_trunc (w, ten19, UNSIGNED, &r);
> + sprintf (buf + c * 19, "%019" PRIu64, r.to_uhwi ());
> + ++c;
> + }
> + l = sprintf (buf2, HOST_WIDE_INT_PRINT_UNSIGNED, w.to_uhwi ());
> + buf[c * 19 + l] = '\0';
> + memcpy (next1, buf, 19);
> + memcpy (buf, buf2, l);
> + for (i = 0; i < c / 2; ++i)
> + {
> + memcpy (next2, buf + (c - i - 1) * 19, 19);
> + memcpy (buf + l + (c - i - 1) * 19, next1, 19);
> + memcpy (next1, buf + (i + 1) * 19, 19);
> + memcpy (buf + l + i * 19, next2, 19);
> + }
> + if (c & 1)
> + memcpy (buf + l + i * 19, next1, 19);
> + }
> }
>
> -/* Try to print the signed self in decimal to FILE if the number fits
> - in a HWI. Other print in hex. */
> +/* Try to print the signed self in decimal to FILE. */
>
> void
> print_decu (const wide_int_ref &wi, FILE *file)
> @@ -155,8 +183,7 @@ void
> pp_wide_int_large (pretty_printer *pp, const wide_int_ref &w, signop sgn)
> {
> unsigned int len;
> - if (!print_dec_buf_size (w, sgn, &len))
> - len = WIDE_INT_PRINT_BUFFER_SIZE;
> + print_dec_buf_size (w, sgn, &len);
> char *buf = XALLOCAVEC (char, len);
> print_dec (w, buf, sgn);
> pp_string (pp, buf);
> --- gcc/pretty-print.h.jj 2023-10-15 23:04:06.095422965 +0200
> +++ gcc/pretty-print.h 2023-10-16 10:51:56.053529117 +0200
> @@ -448,8 +448,9 @@ pp_wide_integer (pretty_printer *pp, HOS
> inline void
> pp_wide_int (pretty_printer *pp, const wide_int_ref &w, signop sgn)
> {
> - unsigned int prec = w.get_precision ();
> - if (UNLIKELY ((prec + 3) / 4 > sizeof (pp_buffer (pp)->digit_buffer) - 3))
> + unsigned int len;
> + print_dec_buf_size (w, sgn, &len);
> + if (UNLIKELY (len > sizeof (pp_buffer (pp)->digit_buffer)))
> pp_wide_int_large (pp, w, sgn);
> else
> {
> --- gcc/tree-pretty-print.cc.jj 2023-09-21 20:02:53.467522151 +0200
> +++ gcc/tree-pretty-print.cc 2023-10-16 11:05:51.131997367 +0200
> @@ -2248,10 +2248,11 @@ dump_generic_node (pretty_printer *pp, t
> pp_minus (pp);
> val = -val;
> }
> - unsigned int prec = val.get_precision ();
> - if ((prec + 3) / 4 > sizeof (pp_buffer (pp)->digit_buffer) - 3)
> + unsigned int len;
> + print_hex_buf_size (val, &len);
> + if (UNLIKELY (len > sizeof (pp_buffer (pp)->digit_buffer)))
> {
> - char *buf = XALLOCAVEC (char, (prec + 3) / 4 + 3);
> + char *buf = XALLOCAVEC (char, len);
> print_hex (val, buf);
> pp_string (pp, buf);
> }
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
