Fix strtod rounding (bug 3479).

1 files changed, 131 insertions, 0 deletions

diff --git a/stdlib/gen-tst-strtod-round.c b/stdlib/gen-tst-strtod-round.c
new file mode 100644
index 0000000000..0a89ff71af
--- /dev/null
+++ b/stdlib/gen-tst-strtod-round.c
@@ -0,0 +1,131 @@
+/* Generate table of tests in tst-strtod-round.c from
+   tst-strtod-round-data.
+   Copyright (C) 2012 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/>.  */
+
+#define _GNU_SOURCE
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.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);
+  mpfr_subnormalize (f, r, rnd);
+  mpfr_clear (f2);
+  return r0 | r;
+#else
+  int r = mpfr_strtofr (f, s, NULL, 0, rnd);
+  mpfr_subnormalize (f, r, rnd);
+  return r;
+#endif
+}
+
+static void
+print_fp (mpfr_t f, const char *suffix, const char *suffix2)
+{
+  if (mpfr_inf_p (f))
+    mpfr_printf ("\t%sINFINITY%s", mpfr_signbit (f) ? "-" : "", suffix2);
+  else
+    mpfr_printf ("\t%Ra%s%s", f, suffix, suffix2);
+}
+
+static void
+round_str (const char *s, const char *suffix,
+	   int prec, int emin, int emax, bool need_exact)
+{
+  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 (need_exact)
+    mpfr_printf ("\t%s,\n", r ? "false" : "true");
+  print_fp (f, suffix, ",\n");
+  string_to_fp (f, s, MPFR_RNDN);
+  print_fp (f, suffix, ",\n");
+  string_to_fp (f, s, MPFR_RNDZ);
+  print_fp (f, suffix, ",\n");
+  string_to_fp (f, s, MPFR_RNDU);
+  print_fp (f, suffix, "");
+  mpfr_clear (f);
+}
+
+static void
+round_for_all (const char *s)
+{
+  static const struct fmt {
+    const char *suffix;
+    int prec;
+    int emin;
+    int emax;
+    bool need_exact;
+  } formats[6] = {
+    { "f", 24, -148, 128, false },
+    { "", 53, -1073, 1024, false },
+    { "L", 53, -1073, 1024, false },
+    { "L", 64, -16444, 16384, false },
+    { "L", 106, -1073, 1024, true },
+    { "L", 113, -16493, 16384, false },
+  };
+  mpfr_printf ("  TEST (\"");
+  const char *p;
+  for (p = s; *p; p++)
+    {
+      putchar (*p);
+      if ((p - s) % 60 == 59 && p[1])
+	mpfr_printf ("\"\n\t\"");
+    }
+  mpfr_printf ("\",\n");
+  int i;
+  for (i = 0; i < 6; i++)
+    {
+      round_str (s, formats[i].suffix, formats[i].prec,
+		 formats[i].emin, formats[i].emax, formats[i].need_exact);
+      if (i < 5)
+	mpfr_printf (",\n");
+    }
+  mpfr_printf ("),\n");
+}
+
+int
+main (void)
+{
+  char *p = NULL;
+  size_t len;
+  ssize_t nbytes;
+  while ((nbytes = getline (&p, &len, stdin)) != -1)
+    {
+      if (p[nbytes - 1] == '\n')
+	p[nbytes - 1] = 0;
+      round_for_all (p);
+      free (p);
+      p = NULL;
+    }
+  return 0;
+}