[PATCH] PR fortran/88227 -- Revenge of the BOZ
Paul Richard Thomas
paul.richard.thomas@gmail.com
Sun Aug 4 14:15:00 GMT 2019
Hi Steve,
This is OK.
Thanks for working on it.
Paul
On Thu, 1 Aug 2019 at 22:13, Steve Kargl
<sgk@troutmask.apl.washington.edu> wrote:
>
> Ping.
>
> --
> steve
>
> On Sun, Jul 28, 2019 at 04:41:02PM -0700, Steve Kargl wrote:
> > The attach patch fixes a problem with the conversion of a
> > BOZ literal constant to a REAL where the size of the REAL
> > exceeds the size of the largest INTEGER. The problem can
> > be seen on 32-bit targets that provide support for REAL(10)
> > and/or REAL(16), or it can be seen with a multilib target
> > when using -m32 and REAL(10) and/or REAL(16).
> >
> > If needed, the patch converts an octal or hexidecimal string
> > to the equivalent binary string, and then converts the binary
> > string to a REAL. In principle, bin2real() can convert to
> > REAL(4), REAL(8), REAL(10), and REAL(16), but I have elected
> > to use the old conversion method if the size of the largest
> > INTEGER exceeds the size the REAL(XXX) of interest. A future
> > patch may remove the old method and make this new approach the
> > only way to convert a BOZ.
> >
> > I have attached a short test program. There is no testcase
> > for testsuite.
> >
> > PLEASE TEST.
> >
> > 2019-07-28 Steven G. Kargl <kargl@gcc.gnu.org>
> >
> > PR fortran/88227
> > * check.c (oct2bin): New function. Convert octal string to binary.
> > (hex2bin): New function. Convert hexidecimal string to binary.
> > (bin2real): New function. Convert binary string to REAL. Use
> > oct2bin and hex2bin.
> > (gfc_boz2real): Use fallback conversion bin2real.
> >
> > --
> > Steve
>
> > Index: gcc/fortran/check.c
> > ===================================================================
> > --- gcc/fortran/check.c (revision 273766)
> > +++ gcc/fortran/check.c (working copy)
> > @@ -55,6 +55,7 @@ gfc_invalid_boz (const char *msg, locus *loc)
> >
> >
> > /* Issue an error for an illegal BOZ argument. */
> > +
> > static bool
> > illegal_boz_arg (gfc_expr *x)
> > {
> > @@ -101,6 +102,167 @@ is_boz_constant (gfc_expr *a)
> > }
> >
> >
> > +/* Convert a octal string into a binary string. This is used in the
> > + fallback conversion of an octal string to a REAL. */
> > +
> > +static char *
> > +oct2bin(int nbits, char *oct)
> > +{
> > + const char bits[8][5] = {
> > + "000", "001", "010", "011", "100", "101", "110", "111"};
> > +
> > + char *buf, *bufp;
> > + int i, j, n;
> > +
> > + j = nbits + 1;
> > + if (nbits == 64) j++;
> > +
> > + bufp = buf = XCNEWVEC (char, j + 1);
> > + memset (bufp, 0, j + 1);
> > +
> > + n = strlen (oct);
> > + for (i = 0; i < n; i++, oct++)
> > + {
> > + j = *oct - 48;
> > + strcpy (bufp, &bits[j][0]);
> > + bufp += 3;
> > + }
> > +
> > + bufp = XCNEWVEC (char, nbits + 1);
> > + if (nbits == 64)
> > + strcpy (bufp, buf + 2);
> > + else
> > + strcpy (bufp, buf + 1);
> > +
> > + free (buf);
> > +
> > + return bufp;
> > +}
> > +
> > +
> > +/* Convert a hexidecimal string into a binary string. This is used in the
> > + fallback conversion of a hexidecimal string to a REAL. */
> > +
> > +static char *
> > +hex2bin(int nbits, char *hex)
> > +{
> > + const char bits[16][5] = {
> > + "0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111",
> > + "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};
> > +
> > + char *buf, *bufp;
> > + int i, j, n;
> > +
> > + bufp = buf = XCNEWVEC (char, nbits + 1);
> > + memset (bufp, 0, nbits + 1);
> > +
> > + n = strlen (hex);
> > + for (i = 0; i < n; i++, hex++)
> > + {
> > + j = *hex;
> > + if (j > 47 && j < 58)
> > + j -= 48;
> > + else if (j > 64 && j < 71)
> > + j -= 55;
> > + else if (j > 96 && j < 103)
> > + j -= 87;
> > + else
> > + gcc_unreachable ();
> > +
> > + strcpy (bufp, &bits[j][0]);
> > + bufp += 4;
> > + }
> > +
> > + return buf;
> > +}
> > +
> > +
> > +/* Fallback conversion of a BOZ string to REAL. */
> > +
> > +static void
> > +bin2real (gfc_expr *x, int kind)
> > +{
> > + char buf[114], *sp;
> > + int b, i, ie, t, w;
> > + bool sgn;
> > + mpz_t em;
> > +
> > + i = gfc_validate_kind (BT_REAL, kind, false);
> > + t = gfc_real_kinds[i].digits - 1;
> > +
> > + /* Number of bits in the exponent. */
> > + if (gfc_real_kinds[i].max_exponent == 16384)
> > + w = 15;
> > + else if (gfc_real_kinds[i].max_exponent == 1024)
> > + w = 11;
> > + else
> > + w = 8;
> > +
> > + if (x->boz.rdx == 16)
> > + sp = hex2bin (gfc_real_kinds[i].mode_precision, x->boz.str);
> > + else if (x->boz.rdx == 8)
> > + sp = oct2bin (gfc_real_kinds[i].mode_precision, x->boz.str);
> > + else
> > + sp = x->boz.str;
> > +
> > + /* Extract sign bit. */
> > + sgn = *sp != '0';
> > +
> > + /* Extract biased exponent. */
> > + memset (buf, 0, 114);
> > + strncpy (buf, ++sp, w);
> > + mpz_init (em);
> > + mpz_set_str (em, buf, 2);
> > + ie = mpz_get_si (em);
> > +
> > + mpfr_init2 (x->value.real, t + 1);
> > + x->ts.type = BT_REAL;
> > + x->ts.kind = kind;
> > +
> > + sp += w; /* Set to first digit in significand. */
> > + b = (1 << w) - 1;
> > + if ((i == 0 && ie == b) || (i == 1 && ie == b)
> > + || ((i == 2 || i == 3) && ie == b))
> > + {
> > + bool zeros = true;
> > + if (i == 2) sp++;
> > + for (; *sp; sp++)
> > + {
> > + if (*sp != '0')
> > + {
> > + zeros = false;
> > + break;
> > + }
> > + }
> > +
> > + if (zeros)
> > + mpfr_set_inf (x->value.real, 1);
> > + else
> > + mpfr_set_nan (x->value.real);
> > + }
> > + else
> > + {
> > + if (i == 2)
> > + strncpy (buf, sp, t + 1);
> > + else
> > + {
> > + /* Significand with hidden bit. */
> > + buf[0] = '1';
> > + strncpy (&buf[1], sp, t);
> > + }
> > +
> > + /* Convert to significand to integer. */
> > + mpz_set_str (em, buf, 2);
> > + ie -= ((1 << (w - 1)) - 1); /* Unbiased exponent. */
> > + mpfr_set_z_2exp (x->value.real, em, ie - t, GFC_RND_MODE);
> > + }
> > +
> > + if (sgn) mpfr_neg (x->value.real, x->value.real, GFC_RND_MODE);
> > +
> > + mpz_clear (em);
> > +}
> > +
> > +
> > /* Fortran 2018 treats a BOZ as simply a string of bits. gfc_boz2real ()
> > converts the string into a REAL of the appropriate kind. The treatment
> > of the sign bit is processor dependent. */
> > @@ -158,21 +320,31 @@ gfc_boz2real (gfc_expr *x, int kind)
> > buf[0] = '1';
> > }
> > }
> > -
> > +
> > /* Reset BOZ string to the truncated or padded version. */
> > free (x->boz.str);
> > x->boz.len = len;
> > x->boz.str = XCNEWVEC (char, len + 1);
> > strncpy (x->boz.str, buf, len);
> >
> > - /* Convert to widest possible integer. */
> > - gfc_boz2int (x, gfc_max_integer_kind);
> > - ts.type = BT_REAL;
> > - ts.kind = kind;
> > - if (!gfc_convert_boz (x, &ts))
> > + /* For some targets, the largest INTEGER in terms of bits is smaller than
> > + the bits needed to hold the REAL. Fortunately, the kind type parameter
> > + indicates the number of bytes required to an INTEGER and a REAL. */
> > + if (gfc_max_integer_kind < kind)
> > {
> > - gfc_error ("Failure in conversion of BOZ to REAL at %L", &x->where);
> > - return false;
> > + bin2real (x, kind);
> > + }
> > + else
> > + {
> > + /* Convert to widest possible integer. */
> > + gfc_boz2int (x, gfc_max_integer_kind);
> > + ts.type = BT_REAL;
> > + ts.kind = kind;
> > + if (!gfc_convert_boz (x, &ts))
> > + {
> > + gfc_error ("Failure in conversion of BOZ to REAL at %L", &x->where);
> > + return false;
> > + }
> > }
> >
> > return true;
>
> > subroutine foo10
> >
> > implicit none
> >
> > real(10) b, o, z, x
> >
> > b = real(b'010000000000000011001001000011111101101010100010001000010110100&
> > &01100000000000000', 10)
> > o = real(o'100001444176652104132140000', 10);
> > z = real(z'4000C90FDAA22168C000', 10)
> > print '(G0/,G0/,G0)', b, o, z
> >
> > b = real(b'011111111111111110000000000000000000000000000000000000000000000&
> > &00000000000000000', 10)
> > o = real(o'177777000000000000000000000', 10)
> > z = real(z'7FFF8000000000000000', 10)
> > print '(3(G0,1X))', b, o, z
> >
> > b = real(b'111111111111111110000000000000000000000000000000000000000000000&
> > &00000000000000000', 10)
> > o = real(o'377777000000000000000000000', 10)
> > z = real(z'FFFF8000000000000000', 10)
> > print '(3(G0,1X))', b, o, z
> >
> > b = real(b'111111111111111111000000000000000000000000000000000000000000000&
> > &00000000000000000', 10)
> > o = real(o'377777400000000000000000000', 10)
> > z = real(z'FFFFC000000000000000', 10)
> > print '(3(G0,1X))', b, o, z
> >
> > b = real(b'011111111111111111000000000000000000000000000000000000000000000&
> > &00000000000000000', 10)
> > o = real(o'177777400000000000000000000', 10)
> > z = real(z'7FFFC000000000000000', 10)
> > print '(3(G0,1X))', b, o, z
> >
> > end subroutine foo10
> >
> > subroutine foo16
> >
> > implicit none
> >
> > real(16) b, o, z, x
> >
> > b = real(b'010000000000000010010010000111111011010101000100010000101101000&
> > &11000010001101001100010011000110011000101000101110000000110111000', 16)
> > o = real(o'1000011103755242102643021514230630505600670', 16);
> > z = real(z'4000921FB54442D18469898CC51701B8', 16)
> > print '(G0/,G0/,G0)', b, o, z
> >
> > b = real(b'011111111111111100000000000000000000000000000000000000000000000&
> > &00000000000000000000000000000000000000000000000000000000000000000', 16)
> > o = real(o'1777760000000000000000000000000000000000000', 16)
> > z = real(z'7FFF0000000000000000000000000000', 16)
> > print '(3(G0,1X))', b, o, z
> >
> > b = real(b'111111111111111100000000000000000000000000000000000000000000000&
> > &00000000000000000000000000000000000000000000000000000000000000000', 16)
> > o = real(o'3777760000000000000000000000000000000000000', 16)
> > z = real(z'FFFF0000000000000000000000000000', 16)
> > print '(3(G0,1X))', b, o, z
> >
> > b = real(b'111111111111111110000000000000000000000000000000000000000000000&
> > &00000000000000000000000000000000000000000000000000000000000000000', 16)
> > o = real(o'3777770000000000000000000000000000000000000', 16)
> > z = real(z'FFFF8000000000000000000000000000', 16)
> > print '(3(G0,1X))', b, o, z
> >
> > b = real(b'011111111111111110000000000000000000000000000000000000000000000&
> > &00000000000000000000000000000000000000000000000000000000000000000', 16)
> > o = real(o'1777770000000000000000000000000000000000000', 16)
> > z = real(z'7FFF8000000000000000000000000000', 16)
> > print '(3(G0,1X))', b, o, z
> >
> > end subroutine foo16
> >
> > program foo
> > call foo10
> > print *
> > call foo16
> > end program foo
>
>
> --
> Steve
> 20170425 https://www.youtube.com/watch?v=VWUpyCsUKR4
> 20161221 https://www.youtube.com/watch?v=IbCHE-hONow
--
"If you can't explain it simply, you don't understand it well enough"
- Albert Einstein
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