glibc/stdlib/gen-tst-strtod-round.c
Joseph Myers 4725d33eed Make strtod raise "inexact" exceptions (bug 19380).
The strtod function should raise the "inexact" exception when its
result is inexact, but fails to do so except in the case of underflow
or overflow.  This patch fixes it to do so for all inexact results.

tst-strtod-round is extended to test for this exception; the generator
is fixed to properly mark inexact results as such in the case where
the inexactness is from the mpfr_subnormalize step.

Tested for x86_64, x86 and powerpc.

	[BZ #19380]
	* stdlib/strtod_l.c (round_and_return): Force "inexact" exception
	for inexact results.
	* stdlib/gen-tst-strtod-round.c (string_to_fp): Return indication
	of inexact result where mpfr_subnormalize is the only inexact
	step.
	* stdlib/tst-strtod-round-data.h: Regenerated.
	* stdlib/tst-strtod-round-skeleton.c [!FE_INEXACT] (FE_INEXACT):
	Define to 0.
	(GEN_ONE_TEST): Test inexact exceptions raised are as expected.
2016-10-28 00:40:23 +00:00

192 lines
4.9 KiB
C

/* Generate table of tests in tst-strtod-round.c from
tst-strtod-round-data.
Copyright (C) 2012-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* Compile this program as:
gcc -std=gnu11 -O2 -Wall -Wextra gen-tst-strtod-round.c -lmpfr \
-o gen-tst-strtod-round
(use of current MPFR version recommended) and run it as:
gen-tst-strtod-round tst-strtod-round-data tst-strtod-round-data.h
The output file will be generated as tst-strtod-round-data.h
*/
#define _GNU_SOURCE
#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <mpfr.h>
/* Work around incorrect ternary value from mpfr_strtofr
<https://sympa.inria.fr/sympa/arc/mpfr/2012-08/msg00005.html>. */
#define WORKAROUND
static int
string_to_fp (mpfr_t f, const char *s, mpfr_rnd_t rnd)
{
#ifdef WORKAROUND
mpfr_t f2;
mpfr_init2 (f2, 100000);
int r0 = mpfr_strtofr (f2, s, NULL, 0, rnd);
int r = mpfr_set (f, f2, rnd);
r |= mpfr_subnormalize (f, r, rnd);
mpfr_clear (f2);
return r0 | r;
#else
int r = mpfr_strtofr (f, s, NULL, 0, rnd);
r |= mpfr_subnormalize (f, r, rnd);
return r;
#endif
}
void
print_fp (FILE *fout, mpfr_t f, const char *suffix)
{
if (mpfr_inf_p (f))
mpfr_fprintf (fout, "\t%sINF%s", mpfr_signbit (f) ? "-" : "", suffix);
else
mpfr_fprintf (fout, "\t%Ra%s", f, suffix);
}
static void
round_str (FILE *fout, const char *s, int prec, int emin, int emax,
bool ibm_ld)
{
mpfr_t f;
mpfr_set_default_prec (prec);
mpfr_set_emin (emin);
mpfr_set_emax (emax);
mpfr_init (f);
int r = string_to_fp (f, s, MPFR_RNDD);
if (ibm_ld)
{
assert (prec == 106 && emin == -1073 && emax == 1024);
/* The maximum value in IBM long double has discontiguous
mantissa bits. */
mpfr_t max_value;
mpfr_init2 (max_value, 107);
mpfr_set_str (max_value, "0x1.fffffffffffff7ffffffffffffcp+1023", 0,
MPFR_RNDN);
if (mpfr_cmpabs (f, max_value) > 0)
r = 1;
mpfr_clear (max_value);
}
mpfr_fprintf (fout, "\t%s,\n", r ? "false" : "true");
print_fp (fout, f, ",\n");
string_to_fp (f, s, MPFR_RNDN);
print_fp (fout, f, ",\n");
string_to_fp (f, s, MPFR_RNDZ);
print_fp (fout, f, ",\n");
string_to_fp (f, s, MPFR_RNDU);
print_fp (fout, f, "");
mpfr_clear (f);
}
static void
round_for_all (FILE *fout, const char *s)
{
static const struct fmt {
int prec;
int emin;
int emax;
bool ibm_ld;
} formats[] = {
{ 24, -148, 128, false },
{ 53, -1073, 1024, false },
/* This is the Intel extended float format. */
{ 64, -16444, 16384, false },
/* This is the Motorola extended float format. */
{ 64, -16445, 16384, false },
{ 106, -1073, 1024, true },
{ 113, -16493, 16384, false },
};
mpfr_fprintf (fout, " TEST (\"");
const char *p;
for (p = s; *p; p++)
{
fputc (*p, fout);
if ((p - s) % 60 == 59 && p[1])
mpfr_fprintf (fout, "\"\n\t\"");
}
mpfr_fprintf (fout, "\",\n");
int i;
int n_formats = sizeof (formats) / sizeof (formats[0]);
for (i = 0; i < n_formats; i++)
{
round_str (fout, s, formats[i].prec, formats[i].emin,
formats[i].emax, formats[i].ibm_ld);
if (i < n_formats - 1)
mpfr_fprintf (fout, ",\n");
}
mpfr_fprintf (fout, "),\n");
}
int
main (int argc, char **argv)
{
char *p = NULL;
size_t len;
ssize_t nbytes;
FILE *fin, *fout;
char *fin_name, *fout_name;
if (argc < 3)
{
fprintf (stderr, "Usage: %s <input> <output>\n", basename (argv[0]));
return EXIT_FAILURE;
}
fin_name = argv[1];
fout_name = argv[2];
fin = fopen (fin_name, "r");
if (fin == NULL)
{
perror ("Could not open input for reading");
return EXIT_FAILURE;
}
fout = fopen (fout_name, "w");
if (fout == NULL)
{
perror ("Could not open output for writing");
return EXIT_FAILURE;
}
fprintf (fout, "/* This file was generated by %s from %s. */\n",
__FILE__, fin_name);
fputs ("static const struct test tests[] = {\n", fout);
while ((nbytes = getline (&p, &len, fin)) != -1)
{
if (p[nbytes - 1] == '\n')
p[nbytes - 1] = 0;
round_for_all (fout, p);
free (p);
p = NULL;
}
fputs ("};\n", fout);
return EXIT_SUCCESS;
}