Add libgmp 6.2.0 to third_party

Don't build it yet.  That will come in the next review.

Change-Id: Idf3266558165e5ab45f4a41c98cc8c838c8244d5
diff --git a/third_party/gmp/tests/mpn/t-hgcd.c b/third_party/gmp/tests/mpn/t-hgcd.c
new file mode 100644
index 0000000..07f83e9
--- /dev/null
+++ b/third_party/gmp/tests/mpn/t-hgcd.c
@@ -0,0 +1,406 @@
+/* Test mpn_hgcd.
+
+Copyright 1991, 1993, 1994, 1996, 1997, 2000-2004 Free Software Foundation,
+Inc.
+
+This file is part of the GNU MP Library test suite.
+
+The GNU MP Library test suite is free software; you can redistribute it
+and/or modify it under the terms of the GNU General Public License as
+published by the Free Software Foundation; either version 3 of the License,
+or (at your option) any later version.
+
+The GNU MP Library test suite 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 General
+Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+the GNU MP Library test suite.  If not, see https://www.gnu.org/licenses/.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "gmp-impl.h"
+#include "tests.h"
+
+static mp_size_t one_test (mpz_t, mpz_t, int);
+static void debug_mp (mpz_t, int);
+
+#define MIN_OPERAND_SIZE 2
+
+/* Fixed values, for regression testing of mpn_hgcd. */
+struct value { int res; const char *a; const char *b; };
+static const struct value hgcd_values[] = {
+#if GMP_NUMB_BITS == 32
+  { 5,
+    "0x1bddff867272a9296ac493c251d7f46f09a5591fe",
+    "0xb55930a2a68a916450a7de006031068c5ddb0e5c" },
+  { 4,
+    "0x2f0ece5b1ee9c15e132a01d55768dc13",
+    "0x1c6f4fd9873cdb24466e6d03e1cc66e7" },
+  { 3, "0x7FFFFC003FFFFFFFFFC5", "0x3FFFFE001FFFFFFFFFE3"},
+#endif
+  { -1, NULL, NULL }
+};
+
+struct hgcd_ref
+{
+  mpz_t m[2][2];
+};
+
+static void hgcd_ref_init (struct hgcd_ref *);
+static void hgcd_ref_clear (struct hgcd_ref *);
+static int hgcd_ref (struct hgcd_ref *, mpz_t, mpz_t);
+static int hgcd_ref_equal (const struct hgcd_matrix *, const struct hgcd_ref *);
+
+int
+main (int argc, char **argv)
+{
+  mpz_t op1, op2, temp1, temp2;
+  int i, j, chain_len;
+  gmp_randstate_ptr rands;
+  mpz_t bs;
+  unsigned long size_range;
+
+  tests_start ();
+  rands = RANDS;
+
+  mpz_init (bs);
+  mpz_init (op1);
+  mpz_init (op2);
+  mpz_init (temp1);
+  mpz_init (temp2);
+
+  for (i = 0; hgcd_values[i].res >= 0; i++)
+    {
+      mp_size_t res;
+
+      mpz_set_str (op1, hgcd_values[i].a, 0);
+      mpz_set_str (op2, hgcd_values[i].b, 0);
+
+      res = one_test (op1, op2, -1-i);
+      if (res != hgcd_values[i].res)
+	{
+	  fprintf (stderr, "ERROR in test %d\n", -1-i);
+	  fprintf (stderr, "Bad return code from hgcd\n");
+	  fprintf (stderr, "op1=");                 debug_mp (op1, -16);
+	  fprintf (stderr, "op2=");                 debug_mp (op2, -16);
+	  fprintf (stderr, "expected: %d\n", hgcd_values[i].res);
+	  fprintf (stderr, "hgcd:     %d\n", (int) res);
+	  abort ();
+	}
+    }
+
+  for (i = 0; i < 15; i++)
+    {
+      /* Generate plain operands with unknown gcd.  These types of operands
+	 have proven to trigger certain bugs in development versions of the
+	 gcd code. */
+
+      mpz_urandomb (bs, rands, 32);
+      size_range = mpz_get_ui (bs) % 13 + 2;
+
+      mpz_urandomb (bs, rands, size_range);
+      mpz_rrandomb (op1, rands, mpz_get_ui (bs) + MIN_OPERAND_SIZE);
+      mpz_urandomb (bs, rands, size_range);
+      mpz_rrandomb (op2, rands, mpz_get_ui (bs) + MIN_OPERAND_SIZE);
+
+      if (mpz_cmp (op1, op2) < 0)
+	mpz_swap (op1, op2);
+
+      if (mpz_size (op1) > 0)
+	one_test (op1, op2, i);
+
+      /* Generate a division chain backwards, allowing otherwise
+	 unlikely huge quotients.  */
+
+      mpz_set_ui (op1, 0);
+      mpz_urandomb (bs, rands, 32);
+      mpz_urandomb (bs, rands, mpz_get_ui (bs) % 16 + 1);
+      mpz_rrandomb (op2, rands, mpz_get_ui (bs));
+      mpz_add_ui (op2, op2, 1);
+
+#if 0
+      chain_len = 1000000;
+#else
+      mpz_urandomb (bs, rands, 32);
+      chain_len = mpz_get_ui (bs) % (GMP_NUMB_BITS * GCD_DC_THRESHOLD / 256);
+#endif
+
+      for (j = 0; j < chain_len; j++)
+	{
+	  mpz_urandomb (bs, rands, 32);
+	  mpz_urandomb (bs, rands, mpz_get_ui (bs) % 12 + 1);
+	  mpz_rrandomb (temp2, rands, mpz_get_ui (bs) + 1);
+	  mpz_add_ui (temp2, temp2, 1);
+	  mpz_mul (temp1, op2, temp2);
+	  mpz_add (op1, op1, temp1);
+
+	  /* Don't generate overly huge operands.  */
+	  if (SIZ (op1) > 3 * GCD_DC_THRESHOLD)
+	    break;
+
+	  mpz_urandomb (bs, rands, 32);
+	  mpz_urandomb (bs, rands, mpz_get_ui (bs) % 12 + 1);
+	  mpz_rrandomb (temp2, rands, mpz_get_ui (bs) + 1);
+	  mpz_add_ui (temp2, temp2, 1);
+	  mpz_mul (temp1, op1, temp2);
+	  mpz_add (op2, op2, temp1);
+
+	  /* Don't generate overly huge operands.  */
+	  if (SIZ (op2) > 3 * GCD_DC_THRESHOLD)
+	    break;
+	}
+      if (mpz_cmp (op1, op2) < 0)
+	mpz_swap (op1, op2);
+
+      if (mpz_size (op1) > 0)
+	one_test (op1, op2, i);
+    }
+
+  mpz_clear (bs);
+  mpz_clear (op1);
+  mpz_clear (op2);
+  mpz_clear (temp1);
+  mpz_clear (temp2);
+
+  tests_end ();
+  exit (0);
+}
+
+static void
+debug_mp (mpz_t x, int base)
+{
+  mpz_out_str (stderr, base, x); fputc ('\n', stderr);
+}
+
+static int
+mpz_mpn_equal (const mpz_t a, mp_srcptr bp, mp_size_t bsize);
+
+static mp_size_t
+one_test (mpz_t a, mpz_t b, int i)
+{
+  struct hgcd_matrix hgcd;
+  struct hgcd_ref ref;
+
+  mpz_t ref_r0;
+  mpz_t ref_r1;
+  mpz_t hgcd_r0;
+  mpz_t hgcd_r1;
+
+  mp_size_t res[2];
+  mp_size_t asize;
+  mp_size_t bsize;
+
+  mp_size_t hgcd_init_scratch;
+  mp_size_t hgcd_scratch;
+
+  mp_ptr hgcd_init_tp;
+  mp_ptr hgcd_tp;
+
+  asize = a->_mp_size;
+  bsize = b->_mp_size;
+
+  ASSERT (asize >= bsize);
+
+  hgcd_init_scratch = MPN_HGCD_MATRIX_INIT_ITCH (asize);
+  hgcd_init_tp = refmpn_malloc_limbs (hgcd_init_scratch);
+  mpn_hgcd_matrix_init (&hgcd, asize, hgcd_init_tp);
+
+  hgcd_scratch = mpn_hgcd_itch (asize);
+  hgcd_tp = refmpn_malloc_limbs (hgcd_scratch);
+
+#if 0
+  fprintf (stderr,
+	   "one_test: i = %d asize = %d, bsize = %d\n",
+	   i, a->_mp_size, b->_mp_size);
+
+  gmp_fprintf (stderr,
+	       "one_test: i = %d\n"
+	       "  a = %Zx\n"
+	       "  b = %Zx\n",
+	       i, a, b);
+#endif
+  hgcd_ref_init (&ref);
+
+  mpz_init_set (ref_r0, a);
+  mpz_init_set (ref_r1, b);
+  res[0] = hgcd_ref (&ref, ref_r0, ref_r1);
+
+  mpz_init_set (hgcd_r0, a);
+  mpz_init_set (hgcd_r1, b);
+  if (bsize < asize)
+    {
+      _mpz_realloc (hgcd_r1, asize);
+      MPN_ZERO (hgcd_r1->_mp_d + bsize, asize - bsize);
+    }
+  res[1] = mpn_hgcd (hgcd_r0->_mp_d,
+		     hgcd_r1->_mp_d,
+		     asize,
+		     &hgcd, hgcd_tp);
+
+  if (res[0] != res[1])
+    {
+      fprintf (stderr, "ERROR in test %d\n", i);
+      fprintf (stderr, "Different return value from hgcd and hgcd_ref\n");
+      fprintf (stderr, "op1=");                 debug_mp (a, -16);
+      fprintf (stderr, "op2=");                 debug_mp (b, -16);
+      fprintf (stderr, "hgcd_ref: %ld\n", (long) res[0]);
+      fprintf (stderr, "mpn_hgcd: %ld\n", (long) res[1]);
+      abort ();
+    }
+  if (res[0] > 0)
+    {
+      if (!hgcd_ref_equal (&hgcd, &ref)
+	  || !mpz_mpn_equal (ref_r0, hgcd_r0->_mp_d, res[1])
+	  || !mpz_mpn_equal (ref_r1, hgcd_r1->_mp_d, res[1]))
+	{
+	  fprintf (stderr, "ERROR in test %d\n", i);
+	  fprintf (stderr, "mpn_hgcd and hgcd_ref returned different values\n");
+	  fprintf (stderr, "op1=");                 debug_mp (a, -16);
+	  fprintf (stderr, "op2=");                 debug_mp (b, -16);
+	  abort ();
+	}
+    }
+
+  refmpn_free_limbs (hgcd_init_tp);
+  refmpn_free_limbs (hgcd_tp);
+  hgcd_ref_clear (&ref);
+  mpz_clear (ref_r0);
+  mpz_clear (ref_r1);
+  mpz_clear (hgcd_r0);
+  mpz_clear (hgcd_r1);
+
+  return res[0];
+}
+
+static void
+hgcd_ref_init (struct hgcd_ref *hgcd)
+{
+  unsigned i;
+  for (i = 0; i<2; i++)
+    {
+      unsigned j;
+      for (j = 0; j<2; j++)
+	mpz_init (hgcd->m[i][j]);
+    }
+}
+
+static void
+hgcd_ref_clear (struct hgcd_ref *hgcd)
+{
+  unsigned i;
+  for (i = 0; i<2; i++)
+    {
+      unsigned j;
+      for (j = 0; j<2; j++)
+	mpz_clear (hgcd->m[i][j]);
+    }
+}
+
+
+static int
+sdiv_qr (mpz_t q, mpz_t r, mp_size_t s, const mpz_t a, const mpz_t b)
+{
+  mpz_fdiv_qr (q, r, a, b);
+  if (mpz_size (r) <= s)
+    {
+      mpz_add (r, r, b);
+      mpz_sub_ui (q, q, 1);
+    }
+
+  return (mpz_sgn (q) > 0);
+}
+
+static int
+hgcd_ref (struct hgcd_ref *hgcd, mpz_t a, mpz_t b)
+{
+  mp_size_t n = MAX (mpz_size (a), mpz_size (b));
+  mp_size_t s = n/2 + 1;
+  mp_size_t asize;
+  mp_size_t bsize;
+  mpz_t q;
+  int res;
+
+  if (mpz_size (a) <= s || mpz_size (b) <= s)
+    return 0;
+
+  res = mpz_cmp (a, b);
+  if (res < 0)
+    {
+      mpz_sub (b, b, a);
+      if (mpz_size (b) <= s)
+	return 0;
+
+      mpz_set_ui (hgcd->m[0][0], 1); mpz_set_ui (hgcd->m[0][1], 0);
+      mpz_set_ui (hgcd->m[1][0], 1); mpz_set_ui (hgcd->m[1][1], 1);
+    }
+  else if (res > 0)
+    {
+      mpz_sub (a, a, b);
+      if (mpz_size (a) <= s)
+	return 0;
+
+      mpz_set_ui (hgcd->m[0][0], 1); mpz_set_ui (hgcd->m[0][1], 1);
+      mpz_set_ui (hgcd->m[1][0], 0); mpz_set_ui (hgcd->m[1][1], 1);
+    }
+  else
+    return 0;
+
+  mpz_init (q);
+
+  for (;;)
+    {
+      ASSERT (mpz_size (a) > s);
+      ASSERT (mpz_size (b) > s);
+
+      if (mpz_cmp (a, b) > 0)
+	{
+	  if (!sdiv_qr (q, a, s, a, b))
+	    break;
+	  mpz_addmul (hgcd->m[0][1], q, hgcd->m[0][0]);
+	  mpz_addmul (hgcd->m[1][1], q, hgcd->m[1][0]);
+	}
+      else
+	{
+	  if (!sdiv_qr (q, b, s, b, a))
+	    break;
+	  mpz_addmul (hgcd->m[0][0], q, hgcd->m[0][1]);
+	  mpz_addmul (hgcd->m[1][0], q, hgcd->m[1][1]);
+	}
+    }
+
+  mpz_clear (q);
+
+  asize = mpz_size (a);
+  bsize = mpz_size (b);
+  return MAX (asize, bsize);
+}
+
+static int
+mpz_mpn_equal (const mpz_t a, mp_srcptr bp, mp_size_t bsize)
+{
+  mp_srcptr ap = a->_mp_d;
+  mp_size_t asize = a->_mp_size;
+
+  MPN_NORMALIZE (bp, bsize);
+  return asize == bsize && mpn_cmp (ap, bp, asize) == 0;
+}
+
+static int
+hgcd_ref_equal (const struct hgcd_matrix *hgcd, const struct hgcd_ref *ref)
+{
+  unsigned i;
+
+  for (i = 0; i<2; i++)
+    {
+      unsigned j;
+
+      for (j = 0; j<2; j++)
+	if (!mpz_mpn_equal (ref->m[i][j], hgcd->p[i][j], hgcd->n))
+	  return 0;
+    }
+
+  return 1;
+}