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diff --git a/gmp/mpn/generic/pre_divrem_1.c b/gmp/mpn/generic/pre_divrem_1.c
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+/* mpn_preinv_divrem_1 -- mpn by limb division with pre-inverted divisor.
+
+   THE FUNCTIONS IN THIS FILE ARE FOR INTERNAL USE ONLY.  THEY'RE ALMOST
+   CERTAIN TO BE SUBJECT TO INCOMPATIBLE CHANGES OR DISAPPEAR COMPLETELY IN
+   FUTURE GNU MP RELEASES.
+
+Copyright 2000, 2001, 2002, 2003 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 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.
+
+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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+
+
+/* Don't bloat a shared library with unused code. */
+#if USE_PREINV_DIVREM_1
+
+/* Same test here for skipping one divide step as in mpn_divrem_1.
+
+   The main reason for a separate shift==0 case is that not all CPUs give
+   zero for "n0 >> BITS_PER_MP_LIMB" which would arise in the general case
+   code used on shift==0.  shift==0 is also reasonably common in __mp_bases
+   big_base, for instance base==10 on a 64-bit limb.
+
+   Under shift!=0 it would be possible to call mpn_lshift to adjust the
+   dividend all in one go (into the quotient space say), rather than
+   limb-by-limb in the loop.  This might help if mpn_lshift is a lot faster
+   than what the compiler can generate for EXTRACT.  But this is left to CPU
+   specific implementations to consider, especially since EXTRACT isn't on
+   the dependent chain.
+
+   If size==0 then the result is simply xsize limbs of zeros, but nothing
+   special is done for that, since it wouldn't be a usual call, and
+   certainly never arises from mpn_get_str which is our main caller.  */
+
+mp_limb_t
+mpn_preinv_divrem_1 (mp_ptr qp, mp_size_t xsize,
+		     mp_srcptr ap, mp_size_t size, mp_limb_t d_unnorm,
+		     mp_limb_t dinv, int shift)
+{
+  mp_limb_t  ahigh, qhigh, r;
+  mp_size_t  i;
+  mp_limb_t  n1, n0;
+  mp_limb_t  d;
+
+  ASSERT (xsize >= 0);
+  ASSERT (size >= 1);
+  ASSERT (d_unnorm != 0);
+#if WANT_ASSERT
+  {
+    int        want_shift;
+    mp_limb_t  want_dinv;
+    count_leading_zeros (want_shift, d_unnorm);
+    ASSERT (shift == want_shift);
+    invert_limb (want_dinv, d_unnorm << shift);
+    ASSERT (dinv == want_dinv);
+  }
+#endif
+  /* FIXME: What's the correct overlap rule when xsize!=0? */
+  ASSERT (MPN_SAME_OR_SEPARATE_P (qp+xsize, ap, size));
+
+  ahigh = ap[size-1];
+  d = d_unnorm << shift;
+  qp += (size + xsize - 1);   /* dest high limb */
+
+  if (shift == 0)
+    {
+      /* High quotient limb is 0 or 1, and skip a divide step. */
+      r = ahigh;
+      qhigh = (r >= d);
+      r = (qhigh ? r-d : r);
+      *qp-- = qhigh;
+      size--;
+
+      for (i = size-1; i >= 0; i--)
+	{
+	  n0 = ap[i];
+	  udiv_qrnnd_preinv (*qp, r, r, n0, d, dinv);
+	  qp--;
+	}
+    }
+  else
+    {
+      r = 0;
+      if (ahigh < d_unnorm)
+	{
+	  r = ahigh << shift;
+	  *qp-- = 0;
+	  size--;
+	  if (size == 0)
+	    goto done_integer;
+	}
+
+      n1 = ap[size-1];
+      r |= n1 >> (BITS_PER_MP_LIMB - shift);
+
+      for (i = size-2; i >= 0; i--)
+	{
+	  ASSERT (r < d);
+	  n0 = ap[i];
+	  udiv_qrnnd_preinv (*qp, r, r,
+			     ((n1 << shift) | (n0 >> (BITS_PER_MP_LIMB - shift))),
+			     d, dinv);
+	  qp--;
+	  n1 = n0;
+	}
+      udiv_qrnnd_preinv (*qp, r, r, n1 << shift, d, dinv);
+      qp--;
+    }
+
+ done_integer:
+  for (i = 0; i < xsize; i++)
+    {
+      udiv_qrnnd_preinv (*qp, r, r, CNST_LIMB(0), d, dinv);
+      qp--;
+    }
+
+  return r >> shift;
+}
+
+#endif /* USE_PREINV_DIVREM_1 */