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/mpz/remove.c b/third_party/gmp/mpz/remove.c
new file mode 100644
index 0000000..a655121
--- /dev/null
+++ b/third_party/gmp/mpz/remove.c
@@ -0,0 +1,146 @@
+/* mpz_remove -- divide out a factor and return its multiplicity.
+
+Copyright 1998-2002, 2012 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of either:
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your
+ option) any later version.
+
+or
+
+ * the GNU General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any
+ later version.
+
+or both in parallel, as here.
+
+The GNU MP 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 General Public License
+for more details.
+
+You should have received copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library. If not,
+see https://www.gnu.org/licenses/. */
+
+#include "gmp-impl.h"
+
+mp_bitcnt_t
+mpz_remove (mpz_ptr dest, mpz_srcptr src, mpz_srcptr f)
+{
+ mp_bitcnt_t pwr;
+ mp_srcptr fp;
+ mp_size_t sn, fn, afn;
+ mp_limb_t fp0;
+
+ sn = SIZ (src);
+ fn = SIZ (f);
+ fp = PTR (f);
+ afn = ABS (fn);
+ fp0 = fp[0];
+
+ if (UNLIKELY ((afn <= (fp0 == 1)) /* mpz_cmpabs_ui (f, 1) <= 0 */
+ | (sn == 0)))
+ {
+ /* f = 0 or f = +- 1 or src = 0 */
+ if (afn == 0)
+ DIVIDE_BY_ZERO;
+ mpz_set (dest, src);
+ return 0;
+ }
+
+ if ((fp0 & 1) != 0)
+ { /* f is odd */
+ mp_ptr dp;
+ mp_size_t dn;
+
+ dn = ABS (sn);
+ dp = MPZ_REALLOC (dest, dn);
+
+ pwr = mpn_remove (dp, &dn, PTR(src), dn, PTR(f), afn, ~(mp_bitcnt_t) 0);
+
+ SIZ (dest) = ((pwr & (fn < 0)) ^ (sn < 0)) ? -dn : dn;
+ }
+ else if (afn == (fp0 == 2))
+ { /* mpz_cmpabs_ui (f, 2) == 0 */
+ pwr = mpz_scan1 (src, 0);
+ mpz_div_2exp (dest, src, pwr);
+ if (pwr & (fn < 0)) /*((pwr % 2 == 1) && (SIZ (f) < 0))*/
+ mpz_neg (dest, dest);
+ }
+ else
+ { /* f != +-2 */
+ mpz_t x, rem;
+
+ mpz_init (rem);
+ mpz_init (x);
+
+ pwr = 0;
+ mpz_tdiv_qr (x, rem, src, f);
+ if (SIZ (rem) == 0)
+ {
+ mpz_t fpow[GMP_LIMB_BITS]; /* Really MP_SIZE_T_BITS */
+ int p;
+
+#if WANT_ORIGINAL_DEST
+ mp_ptr dp;
+ dp = PTR (dest);
+#endif
+ /* We could perhaps compute mpz_scan1(src,0)/mpz_scan1(f,0). It is an
+ upper bound of the result we're seeking. We could also shift down the
+ operands so that they become odd, to make intermediate values
+ smaller. */
+ mpz_init_set (fpow[0], f);
+ mpz_swap (dest, x);
+
+ p = 1;
+ /* Divide by f, f^2 ... f^(2^k) until we get a remainder for f^(2^k). */
+ while (ABSIZ (dest) >= 2 * ABSIZ (fpow[p - 1]) - 1)
+ {
+ mpz_init (fpow[p]);
+ mpz_mul (fpow[p], fpow[p - 1], fpow[p - 1]);
+ mpz_tdiv_qr (x, rem, dest, fpow[p]);
+ if (SIZ (rem) != 0) {
+ mpz_clear (fpow[p]);
+ break;
+ }
+ mpz_swap (dest, x);
+ p++;
+ }
+
+ pwr = ((mp_bitcnt_t)1 << p) - 1;
+
+ /* Divide by f^(2^(k-1)), f^(2^(k-2)), ..., f for all divisors that give
+ a zero remainder. */
+ while (--p >= 0)
+ {
+ mpz_tdiv_qr (x, rem, dest, fpow[p]);
+ if (SIZ (rem) == 0)
+ {
+ pwr += (mp_bitcnt_t)1 << p;
+ mpz_swap (dest, x);
+ }
+ mpz_clear (fpow[p]);
+ }
+
+#if WANT_ORIGINAL_DEST
+ if (PTR (x) == dp) {
+ mpz_swap (dest, x);
+ mpz_set (dest, x);
+ }
+#endif
+ }
+ else
+ mpz_set (dest, src);
+
+ mpz_clear (x);
+ mpz_clear (rem);
+ }
+
+ return pwr;
+}