Initial check-in of gcc 4.7.2.

Change-Id: I4a2f5a921c21741a0e18bda986d77e5f1bef0365

1 files changed, 1144 insertions, 0 deletions

diff --git a/gcc-4.7/gcc/double-int.c b/gcc-4.7/gcc/double-int.c
new file mode 100644
index 000000000..d0fde0ed8
--- /dev/null
+++ b/gcc-4.7/gcc/double-int.c
@@ -0,0 +1,1144 @@
+/* Operations with long integers.
+   Copyright (C) 2006, 2007, 2009, 2010 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC 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, or (at your option) any
+later version.
+
+GCC 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 GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"			/* For SHIFT_COUNT_TRUNCATED.  */
+#include "tree.h"
+
+/* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
+   overflow.  Suppose A, B and SUM have the same respective signs as A1, B1,
+   and SUM1.  Then this yields nonzero if overflow occurred during the
+   addition.
+
+   Overflow occurs if A and B have the same sign, but A and SUM differ in
+   sign.  Use `^' to test whether signs differ, and `< 0' to isolate the
+   sign.  */
+#define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
+
+/* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
+   We do that by representing the two-word integer in 4 words, with only
+   HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
+   number.  The value of the word is LOWPART + HIGHPART * BASE.  */
+
+#define LOWPART(x) \
+  ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
+#define HIGHPART(x) \
+  ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
+#define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
+
+/* Unpack a two-word integer into 4 words.
+   LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
+   WORDS points to the array of HOST_WIDE_INTs.  */
+
+static void
+encode (HOST_WIDE_INT *words, unsigned HOST_WIDE_INT low, HOST_WIDE_INT hi)
+{
+  words[0] = LOWPART (low);
+  words[1] = HIGHPART (low);
+  words[2] = LOWPART (hi);
+  words[3] = HIGHPART (hi);
+}
+
+/* Pack an array of 4 words into a two-word integer.
+   WORDS points to the array of words.
+   The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces.  */
+
+static void
+decode (HOST_WIDE_INT *words, unsigned HOST_WIDE_INT *low,
+	HOST_WIDE_INT *hi)
+{
+  *low = words[0] + words[1] * BASE;
+  *hi = words[2] + words[3] * BASE;
+}
+
+/* Add two doubleword integers with doubleword result.
+   Return nonzero if the operation overflows according to UNSIGNED_P.
+   Each argument is given as two `HOST_WIDE_INT' pieces.
+   One argument is L1 and H1; the other, L2 and H2.
+   The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.  */
+
+int
+add_double_with_sign (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
+		      unsigned HOST_WIDE_INT l2, HOST_WIDE_INT h2,
+		      unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv,
+		      bool unsigned_p)
+{
+  unsigned HOST_WIDE_INT l;
+  HOST_WIDE_INT h;
+
+  l = l1 + l2;
+  h = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) h1
+		       + (unsigned HOST_WIDE_INT) h2
+		       + (l < l1));
+
+  *lv = l;
+  *hv = h;
+
+  if (unsigned_p)
+    return ((unsigned HOST_WIDE_INT) h < (unsigned HOST_WIDE_INT) h1
+	    || (h == h1
+		&& l < l1));
+  else
+    return OVERFLOW_SUM_SIGN (h1, h2, h);
+}
+
+/* Negate a doubleword integer with doubleword result.
+   Return nonzero if the operation overflows, assuming it's signed.
+   The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
+   The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.  */
+
+int
+neg_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
+	    unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv)
+{
+  if (l1 == 0)
+    {
+      *lv = 0;
+      *hv = - h1;
+      return (*hv & h1) < 0;
+    }
+  else
+    {
+      *lv = -l1;
+      *hv = ~h1;
+      return 0;
+    }
+}
+
+/* Multiply two doubleword integers with doubleword result.
+   Return nonzero if the operation overflows according to UNSIGNED_P.
+   Each argument is given as two `HOST_WIDE_INT' pieces.
+   One argument is L1 and H1; the other, L2 and H2.
+   The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.  */
+
+int
+mul_double_with_sign (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
+		      unsigned HOST_WIDE_INT l2, HOST_WIDE_INT h2,
+		      unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv,
+		      bool unsigned_p)
+{
+  HOST_WIDE_INT arg1[4];
+  HOST_WIDE_INT arg2[4];
+  HOST_WIDE_INT prod[4 * 2];
+  unsigned HOST_WIDE_INT carry;
+  int i, j, k;
+  unsigned HOST_WIDE_INT toplow, neglow;
+  HOST_WIDE_INT tophigh, neghigh;
+
+  encode (arg1, l1, h1);
+  encode (arg2, l2, h2);
+
+  memset (prod, 0, sizeof prod);
+
+  for (i = 0; i < 4; i++)
+    {
+      carry = 0;
+      for (j = 0; j < 4; j++)
+	{
+	  k = i + j;
+	  /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000.  */
+	  carry += arg1[i] * arg2[j];
+	  /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF.  */
+	  carry += prod[k];
+	  prod[k] = LOWPART (carry);
+	  carry = HIGHPART (carry);
+	}
+      prod[i + 4] = carry;
+    }
+
+  decode (prod, lv, hv);
+  decode (prod + 4, &toplow, &tophigh);
+
+  /* Unsigned overflow is immediate.  */
+  if (unsigned_p)
+    return (toplow | tophigh) != 0;
+
+  /* Check for signed overflow by calculating the signed representation of the
+     top half of the result; it should agree with the low half's sign bit.  */
+  if (h1 < 0)
+    {
+      neg_double (l2, h2, &neglow, &neghigh);
+      add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
+    }
+  if (h2 < 0)
+    {
+      neg_double (l1, h1, &neglow, &neghigh);
+      add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
+    }
+  return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
+}
+
+/* Shift the doubleword integer in L1, H1 right by COUNT places
+   keeping only PREC bits of result.  ARITH nonzero specifies
+   arithmetic shifting; otherwise use logical shift.
+   Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV.  */
+
+static void
+rshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
+	       unsigned HOST_WIDE_INT count, unsigned int prec,
+	       unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv,
+	       bool arith)
+{
+  unsigned HOST_WIDE_INT signmask;
+
+  signmask = (arith
+	      ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
+	      : 0);
+
+  if (SHIFT_COUNT_TRUNCATED)
+    count %= prec;
+
+  if (count >= 2 * HOST_BITS_PER_WIDE_INT)
+    {
+      /* Shifting by the host word size is undefined according to the
+	 ANSI standard, so we must handle this as a special case.  */
+      *hv = 0;
+      *lv = 0;
+    }
+  else if (count >= HOST_BITS_PER_WIDE_INT)
+    {
+      *hv = 0;
+      *lv = (unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT);
+    }
+  else
+    {
+      *hv = (unsigned HOST_WIDE_INT) h1 >> count;
+      *lv = ((l1 >> count)
+	     | ((unsigned HOST_WIDE_INT) h1
+		<< (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
+    }
+
+  /* Zero / sign extend all bits that are beyond the precision.  */
+
+  if (count >= prec)
+    {
+      *hv = signmask;
+      *lv = signmask;
+    }
+  else if ((prec - count) >= 2 * HOST_BITS_PER_WIDE_INT)
+    ;
+  else if ((prec - count) >= HOST_BITS_PER_WIDE_INT)
+    {
+      *hv &= ~((HOST_WIDE_INT) (-1) << (prec - count - HOST_BITS_PER_WIDE_INT));
+      *hv |= signmask << (prec - count - HOST_BITS_PER_WIDE_INT);
+    }
+  else
+    {
+      *hv = signmask;
+      *lv &= ~((unsigned HOST_WIDE_INT) (-1) << (prec - count));
+      *lv |= signmask << (prec - count);
+    }
+}
+
+/* Shift the doubleword integer in L1, H1 left by COUNT places
+   keeping only PREC bits of result.
+   Shift right if COUNT is negative.
+   ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
+   Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV.  */
+
+void
+lshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
+	       HOST_WIDE_INT count, unsigned int prec,
+	       unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv, bool arith)
+{
+  unsigned HOST_WIDE_INT signmask;
+
+  if (count < 0)
+    {
+      rshift_double (l1, h1, absu_hwi (count), prec, lv, hv, arith);
+      return;
+    }
+
+  if (SHIFT_COUNT_TRUNCATED)
+    count %= prec;
+
+  if (count >= 2 * HOST_BITS_PER_WIDE_INT)
+    {
+      /* Shifting by the host word size is undefined according to the
+	 ANSI standard, so we must handle this as a special case.  */
+      *hv = 0;
+      *lv = 0;
+    }
+  else if (count >= HOST_BITS_PER_WIDE_INT)
+    {
+      *hv = l1 << (count - HOST_BITS_PER_WIDE_INT);
+      *lv = 0;
+    }
+  else
+    {
+      *hv = (((unsigned HOST_WIDE_INT) h1 << count)
+	     | (l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
+      *lv = l1 << count;
+    }
+
+  /* Sign extend all bits that are beyond the precision.  */
+
+  signmask = -((prec > HOST_BITS_PER_WIDE_INT
+		? ((unsigned HOST_WIDE_INT) *hv
+		   >> (prec - HOST_BITS_PER_WIDE_INT - 1))
+		: (*lv >> (prec - 1))) & 1);
+
+  if (prec >= 2 * HOST_BITS_PER_WIDE_INT)
+    ;
+  else if (prec >= HOST_BITS_PER_WIDE_INT)
+    {
+      *hv &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
+      *hv |= signmask << (prec - HOST_BITS_PER_WIDE_INT);
+    }
+  else
+    {
+      *hv = signmask;
+      *lv &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
+      *lv |= signmask << prec;
+    }
+}
+
+/* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
+   for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
+   CODE is a tree code for a kind of division, one of
+   TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
+   or EXACT_DIV_EXPR
+   It controls how the quotient is rounded to an integer.
+   Return nonzero if the operation overflows.
+   UNS nonzero says do unsigned division.  */
+
+int
+div_and_round_double (unsigned code, int uns,
+		      /* num == numerator == dividend */
+		      unsigned HOST_WIDE_INT lnum_orig,
+		      HOST_WIDE_INT hnum_orig,
+		      /* den == denominator == divisor */
+		      unsigned HOST_WIDE_INT lden_orig,
+		      HOST_WIDE_INT hden_orig,
+		      unsigned HOST_WIDE_INT *lquo,
+		      HOST_WIDE_INT *hquo, unsigned HOST_WIDE_INT *lrem,
+		      HOST_WIDE_INT *hrem)
+{
+  int quo_neg = 0;
+  HOST_WIDE_INT num[4 + 1];	/* extra element for scaling.  */
+  HOST_WIDE_INT den[4], quo[4];
+  int i, j;
+  unsigned HOST_WIDE_INT work;
+  unsigned HOST_WIDE_INT carry = 0;
+  unsigned HOST_WIDE_INT lnum = lnum_orig;
+  HOST_WIDE_INT hnum = hnum_orig;
+  unsigned HOST_WIDE_INT lden = lden_orig;
+  HOST_WIDE_INT hden = hden_orig;
+  int overflow = 0;
+
+  if (hden == 0 && lden == 0)
+    overflow = 1, lden = 1;
+
+  /* Calculate quotient sign and convert operands to unsigned.  */
+  if (!uns)
+    {
+      if (hnum < 0)
+	{
+	  quo_neg = ~ quo_neg;
+	  /* (minimum integer) / (-1) is the only overflow case.  */
+	  if (neg_double (lnum, hnum, &lnum, &hnum)
+	      && ((HOST_WIDE_INT) lden & hden) == -1)
+	    overflow = 1;
+	}
+      if (hden < 0)
+	{
+	  quo_neg = ~ quo_neg;
+	  neg_double (lden, hden, &lden, &hden);
+	}
+    }
+
+  if (hnum == 0 && hden == 0)
+    {				/* single precision */
+      *hquo = *hrem = 0;
+      /* This unsigned division rounds toward zero.  */
+      *lquo = lnum / lden;
+      goto finish_up;
+    }
+
+  if (hnum == 0)
+    {				/* trivial case: dividend < divisor */
+      /* hden != 0 already checked.  */
+      *hquo = *lquo = 0;
+      *hrem = hnum;
+      *lrem = lnum;
+      goto finish_up;
+    }
+
+  memset (quo, 0, sizeof quo);
+
+  memset (num, 0, sizeof num);	/* to zero 9th element */
+  memset (den, 0, sizeof den);
+
+  encode (num, lnum, hnum);
+  encode (den, lden, hden);
+
+  /* Special code for when the divisor < BASE.  */
+  if (hden == 0 && lden < (unsigned HOST_WIDE_INT) BASE)
+    {
+      /* hnum != 0 already checked.  */
+      for (i = 4 - 1; i >= 0; i--)
+	{
+	  work = num[i] + carry * BASE;
+	  quo[i] = work / lden;
+	  carry = work % lden;
+	}
+    }
+  else
+    {
+      /* Full double precision division,
+	 with thanks to Don Knuth's "Seminumerical Algorithms".  */
+      int num_hi_sig, den_hi_sig;
+      unsigned HOST_WIDE_INT quo_est, scale;
+
+      /* Find the highest nonzero divisor digit.  */
+      for (i = 4 - 1;; i--)
+	if (den[i] != 0)
+	  {
+	    den_hi_sig = i;
+	    break;
+	  }
+
+      /* Insure that the first digit of the divisor is at least BASE/2.
+	 This is required by the quotient digit estimation algorithm.  */
+
+      scale = BASE / (den[den_hi_sig] + 1);
+      if (scale > 1)
+	{		/* scale divisor and dividend */
+	  carry = 0;
+	  for (i = 0; i <= 4 - 1; i++)
+	    {
+	      work = (num[i] * scale) + carry;
+	      num[i] = LOWPART (work);
+	      carry = HIGHPART (work);
+	    }
+
+	  num[4] = carry;
+	  carry = 0;
+	  for (i = 0; i <= 4 - 1; i++)
+	    {
+	      work = (den[i] * scale) + carry;
+	      den[i] = LOWPART (work);
+	      carry = HIGHPART (work);
+	      if (den[i] != 0) den_hi_sig = i;
+	    }
+	}
+
+      num_hi_sig = 4;
+
+      /* Main loop */
+      for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--)
+	{
+	  /* Guess the next quotient digit, quo_est, by dividing the first
+	     two remaining dividend digits by the high order quotient digit.
+	     quo_est is never low and is at most 2 high.  */
+	  unsigned HOST_WIDE_INT tmp;
+
+	  num_hi_sig = i + den_hi_sig + 1;
+	  work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
+	  if (num[num_hi_sig] != den[den_hi_sig])
+	    quo_est = work / den[den_hi_sig];
+	  else
+	    quo_est = BASE - 1;
+
+	  /* Refine quo_est so it's usually correct, and at most one high.  */
+	  tmp = work - quo_est * den[den_hi_sig];
+	  if (tmp < BASE
+	      && (den[den_hi_sig - 1] * quo_est
+		  > (tmp * BASE + num[num_hi_sig - 2])))
+	    quo_est--;
+
+	  /* Try QUO_EST as the quotient digit, by multiplying the
+	     divisor by QUO_EST and subtracting from the remaining dividend.
+	     Keep in mind that QUO_EST is the I - 1st digit.  */
+
+	  carry = 0;
+	  for (j = 0; j <= den_hi_sig; j++)
+	    {
+	      work = quo_est * den[j] + carry;
+	      carry = HIGHPART (work);
+	      work = num[i + j] - LOWPART (work);
+	      num[i + j] = LOWPART (work);
+	      carry += HIGHPART (work) != 0;
+	    }
+
+	  /* If quo_est was high by one, then num[i] went negative and
+	     we need to correct things.  */
+	  if (num[num_hi_sig] < (HOST_WIDE_INT) carry)
+	    {
+	      quo_est--;
+	      carry = 0;		/* add divisor back in */
+	      for (j = 0; j <= den_hi_sig; j++)
+		{
+		  work = num[i + j] + den[j] + carry;
+		  carry = HIGHPART (work);
+		  num[i + j] = LOWPART (work);
+		}
+
+	      num [num_hi_sig] += carry;
+	    }
+
+	  /* Store the quotient digit.  */
+	  quo[i] = quo_est;
+	}
+    }
+
+  decode (quo, lquo, hquo);
+
+ finish_up:
+  /* If result is negative, make it so.  */
+  if (quo_neg)
+    neg_double (*lquo, *hquo, lquo, hquo);
+
+  /* Compute trial remainder:  rem = num - (quo * den)  */
+  mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
+  neg_double (*lrem, *hrem, lrem, hrem);
+  add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
+
+  switch (code)
+    {
+    case TRUNC_DIV_EXPR:
+    case TRUNC_MOD_EXPR:	/* round toward zero */
+    case EXACT_DIV_EXPR:	/* for this one, it shouldn't matter */
+      return overflow;
+
+    case FLOOR_DIV_EXPR:
+    case FLOOR_MOD_EXPR:	/* round toward negative infinity */
+      if (quo_neg && (*lrem != 0 || *hrem != 0))   /* ratio < 0 && rem != 0 */
+	{
+	  /* quo = quo - 1;  */
+	  add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT)  -1,
+		      lquo, hquo);
+	}
+      else
+	return overflow;
+      break;
+
+    case CEIL_DIV_EXPR:
+    case CEIL_MOD_EXPR:		/* round toward positive infinity */
+      if (!quo_neg && (*lrem != 0 || *hrem != 0))  /* ratio > 0 && rem != 0 */
+	{
+	  add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
+		      lquo, hquo);
+	}
+      else
+	return overflow;
+      break;
+
+    case ROUND_DIV_EXPR:
+    case ROUND_MOD_EXPR:	/* round to closest integer */
+      {
+	unsigned HOST_WIDE_INT labs_rem = *lrem;
+	HOST_WIDE_INT habs_rem = *hrem;
+	unsigned HOST_WIDE_INT labs_den = lden, ltwice;
+	HOST_WIDE_INT habs_den = hden, htwice;
+
+	/* Get absolute values.  */
+	if (*hrem < 0)
+	  neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
+	if (hden < 0)
+	  neg_double (lden, hden, &labs_den, &habs_den);
+
+	/* If (2 * abs (lrem) >= abs (lden)), adjust the quotient.  */
+	mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
+		    labs_rem, habs_rem, &ltwice, &htwice);
+
+	if (((unsigned HOST_WIDE_INT) habs_den
+	     < (unsigned HOST_WIDE_INT) htwice)
+	    || (((unsigned HOST_WIDE_INT) habs_den
+		 == (unsigned HOST_WIDE_INT) htwice)
+		&& (labs_den <= ltwice)))
+	  {
+	    if (*hquo < 0)
+	      /* quo = quo - 1;  */
+	      add_double (*lquo, *hquo,
+			  (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
+	    else
+	      /* quo = quo + 1; */
+	      add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
+			  lquo, hquo);
+	  }
+	else
+	  return overflow;
+      }
+      break;
+
+    default:
+      gcc_unreachable ();
+    }
+
+  /* Compute true remainder:  rem = num - (quo * den)  */
+  mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
+  neg_double (*lrem, *hrem, lrem, hrem);
+  add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
+  return overflow;
+}
+
+
+/* Returns mask for PREC bits.  */
+
+double_int
+double_int_mask (unsigned prec)
+{
+  unsigned HOST_WIDE_INT m;
+  double_int mask;
+
+  if (prec > HOST_BITS_PER_WIDE_INT)
+    {
+      prec -= HOST_BITS_PER_WIDE_INT;
+      m = ((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1;
+      mask.high = (HOST_WIDE_INT) m;
+      mask.low = ALL_ONES;
+    }
+  else
+    {
+      mask.high = 0;
+      mask.low = ((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1;
+    }
+
+  return mask;
+}
+
+/* Clears the bits of CST over the precision PREC.  If UNS is false, the bits
+   outside of the precision are set to the sign bit (i.e., the PREC-th one),
+   otherwise they are set to zero.
+
+   This corresponds to returning the value represented by PREC lowermost bits
+   of CST, with the given signedness.  */
+
+double_int
+double_int_ext (double_int cst, unsigned prec, bool uns)
+{
+  if (uns)
+    return double_int_zext (cst, prec);
+  else
+    return double_int_sext (cst, prec);
+}
+
+/* The same as double_int_ext with UNS = true.  */
+
+double_int
+double_int_zext (double_int cst, unsigned prec)
+{
+  double_int mask = double_int_mask (prec);
+  double_int r;
+
+  r.low = cst.low & mask.low;
+  r.high = cst.high & mask.high;
+
+  return r;
+}
+
+/* The same as double_int_ext with UNS = false.  */
+
+double_int
+double_int_sext (double_int cst, unsigned prec)
+{
+  double_int mask = double_int_mask (prec);
+  double_int r;
+  unsigned HOST_WIDE_INT snum;
+
+  if (prec <= HOST_BITS_PER_WIDE_INT)
+    snum = cst.low;
+  else
+    {
+      prec -= HOST_BITS_PER_WIDE_INT;
+      snum = (unsigned HOST_WIDE_INT) cst.high;
+    }
+  if (((snum >> (prec - 1)) & 1) == 1)
+    {
+      r.low = cst.low | ~mask.low;
+      r.high = cst.high | ~mask.high;
+    }
+  else
+    {
+      r.low = cst.low & mask.low;
+      r.high = cst.high & mask.high;
+    }
+
+  return r;
+}
+
+/* Returns true if CST fits in signed HOST_WIDE_INT.  */
+
+bool
+double_int_fits_in_shwi_p (double_int cst)
+{
+  if (cst.high == 0)
+    return (HOST_WIDE_INT) cst.low >= 0;
+  else if (cst.high == -1)
+    return (HOST_WIDE_INT) cst.low < 0;
+  else
+    return false;
+}
+
+/* Returns true if CST fits in HOST_WIDE_INT if UNS is false, or in
+   unsigned HOST_WIDE_INT if UNS is true.  */
+
+bool
+double_int_fits_in_hwi_p (double_int cst, bool uns)
+{
+  if (uns)
+    return double_int_fits_in_uhwi_p (cst);
+  else
+    return double_int_fits_in_shwi_p (cst);
+}
+
+/* Returns A * B.  */
+
+double_int
+double_int_mul (double_int a, double_int b)
+{
+  double_int ret;
+  mul_double (a.low, a.high, b.low, b.high, &ret.low, &ret.high);
+  return ret;
+}
+
+/* Returns A * B. If the operation overflows according to UNSIGNED_P,
+   *OVERFLOW is set to nonzero.  */
+
+double_int
+double_int_mul_with_sign (double_int a, double_int b,
+                          bool unsigned_p, int *overflow)
+{
+  double_int ret;
+  *overflow = mul_double_with_sign (a.low, a.high, b.low, b.high,
+                                    &ret.low, &ret.high, unsigned_p);
+  return ret;
+}
+
+/* Returns A + B.  */
+
+double_int
+double_int_add (double_int a, double_int b)
+{
+  double_int ret;
+  add_double (a.low, a.high, b.low, b.high, &ret.low, &ret.high);
+  return ret;
+}
+
+/* Returns A - B.  */
+
+double_int
+double_int_sub (double_int a, double_int b)
+{
+  double_int ret;
+  neg_double (b.low, b.high, &b.low, &b.high);
+  add_double (a.low, a.high, b.low, b.high, &ret.low, &ret.high);
+  return ret;
+}
+
+/* Returns -A.  */
+
+double_int
+double_int_neg (double_int a)
+{
+  double_int ret;
+  neg_double (a.low, a.high, &ret.low, &ret.high);
+  return ret;
+}
+
+/* Returns A / B (computed as unsigned depending on UNS, and rounded as
+   specified by CODE).  CODE is enum tree_code in fact, but double_int.h
+   must be included before tree.h.  The remainder after the division is
+   stored to MOD.  */
+
+double_int
+double_int_divmod (double_int a, double_int b, bool uns, unsigned code,
+		   double_int *mod)
+{
+  double_int ret;
+
+  div_and_round_double (code, uns, a.low, a.high,
+			b.low, b.high, &ret.low, &ret.high,
+			&mod->low, &mod->high);
+  return ret;
+}
+
+/* The same as double_int_divmod with UNS = false.  */
+
+double_int
+double_int_sdivmod (double_int a, double_int b, unsigned code, double_int *mod)
+{
+  return double_int_divmod (a, b, false, code, mod);
+}
+
+/* The same as double_int_divmod with UNS = true.  */
+
+double_int
+double_int_udivmod (double_int a, double_int b, unsigned code, double_int *mod)
+{
+  return double_int_divmod (a, b, true, code, mod);
+}
+
+/* Returns A / B (computed as unsigned depending on UNS, and rounded as
+   specified by CODE).  CODE is enum tree_code in fact, but double_int.h
+   must be included before tree.h.  */
+
+double_int
+double_int_div (double_int a, double_int b, bool uns, unsigned code)
+{
+  double_int mod;
+
+  return double_int_divmod (a, b, uns, code, &mod);
+}
+
+/* The same as double_int_div with UNS = false.  */
+
+double_int
+double_int_sdiv (double_int a, double_int b, unsigned code)
+{
+  return double_int_div (a, b, false, code);
+}
+
+/* The same as double_int_div with UNS = true.  */
+
+double_int
+double_int_udiv (double_int a, double_int b, unsigned code)
+{
+  return double_int_div (a, b, true, code);
+}
+
+/* Returns A % B (computed as unsigned depending on UNS, and rounded as
+   specified by CODE).  CODE is enum tree_code in fact, but double_int.h
+   must be included before tree.h.  */
+
+double_int
+double_int_mod (double_int a, double_int b, bool uns, unsigned code)
+{
+  double_int mod;
+
+  double_int_divmod (a, b, uns, code, &mod);
+  return mod;
+}
+
+/* The same as double_int_mod with UNS = false.  */
+
+double_int
+double_int_smod (double_int a, double_int b, unsigned code)
+{
+  return double_int_mod (a, b, false, code);
+}
+
+/* The same as double_int_mod with UNS = true.  */
+
+double_int
+double_int_umod (double_int a, double_int b, unsigned code)
+{
+  return double_int_mod (a, b, true, code);
+}
+
+/* Set BITPOS bit in A.  */
+double_int
+double_int_setbit (double_int a, unsigned bitpos)
+{
+  if (bitpos < HOST_BITS_PER_WIDE_INT)
+    a.low |= (unsigned HOST_WIDE_INT) 1 << bitpos;
+  else
+    a.high |= (HOST_WIDE_INT) 1 <<  (bitpos - HOST_BITS_PER_WIDE_INT);
+ 
+  return a;
+}
+
+/* Count trailing zeros in A.  */
+int
+double_int_ctz (double_int a)
+{
+  unsigned HOST_WIDE_INT w = a.low ? a.low : (unsigned HOST_WIDE_INT) a.high;
+  unsigned bits = a.low ? 0 : HOST_BITS_PER_WIDE_INT;
+  if (!w)
+    return HOST_BITS_PER_DOUBLE_INT;
+  bits += ctz_hwi (w);
+  return bits;
+}
+
+/* Shift A left by COUNT places keeping only PREC bits of result.  Shift
+   right if COUNT is negative.  ARITH true specifies arithmetic shifting;
+   otherwise use logical shift.  */
+
+double_int
+double_int_lshift (double_int a, HOST_WIDE_INT count, unsigned int prec, bool arith)
+{
+  double_int ret;
+  lshift_double (a.low, a.high, count, prec, &ret.low, &ret.high, arith);
+  return ret;
+}
+
+/* Shift A rigth by COUNT places keeping only PREC bits of result.  Shift
+   left if COUNT is negative.  ARITH true specifies arithmetic shifting;
+   otherwise use logical shift.  */
+
+double_int
+double_int_rshift (double_int a, HOST_WIDE_INT count, unsigned int prec, bool arith)
+{
+  double_int ret;
+  lshift_double (a.low, a.high, -count, prec, &ret.low, &ret.high, arith);
+  return ret;
+}
+
+/* Rotate  A left by COUNT places keeping only PREC bits of result.
+   Rotate right if COUNT is negative.  */
+
+double_int
+double_int_lrotate (double_int a, HOST_WIDE_INT count, unsigned int prec)
+{
+  double_int t1, t2;
+
+  count %= prec;
+  if (count < 0)
+    count += prec;
+
+  t1 = double_int_lshift (a, count, prec, false);
+  t2 = double_int_rshift (a, prec - count, prec, false);
+
+  return double_int_ior (t1, t2);
+}
+
+/* Rotate A rigth by COUNT places keeping only PREC bits of result.
+   Rotate right if COUNT is negative.  */
+
+double_int
+double_int_rrotate (double_int a, HOST_WIDE_INT count, unsigned int prec)
+{
+  double_int t1, t2;
+
+  count %= prec;
+  if (count < 0)
+    count += prec;
+
+  t1 = double_int_rshift (a, count, prec, false);
+  t2 = double_int_lshift (a, prec - count, prec, false);
+
+  return double_int_ior (t1, t2);
+}
+
+/* Returns -1 if A < B, 0 if A == B and 1 if A > B.  Signedness of the
+   comparison is given by UNS.  */
+
+int
+double_int_cmp (double_int a, double_int b, bool uns)
+{
+  if (uns)
+    return double_int_ucmp (a, b);
+  else
+    return double_int_scmp (a, b);
+}
+
+/* Compares two unsigned values A and B.  Returns -1 if A < B, 0 if A == B,
+   and 1 if A > B.  */
+
+int
+double_int_ucmp (double_int a, double_int b)
+{
+  if ((unsigned HOST_WIDE_INT) a.high < (unsigned HOST_WIDE_INT) b.high)
+    return -1;
+  if ((unsigned HOST_WIDE_INT) a.high > (unsigned HOST_WIDE_INT) b.high)
+    return 1;
+  if (a.low < b.low)
+    return -1;
+  if (a.low > b.low)
+    return 1;
+
+  return 0;
+}
+
+/* Compares two signed values A and B.  Returns -1 if A < B, 0 if A == B,
+   and 1 if A > B.  */
+
+int
+double_int_scmp (double_int a, double_int b)
+{
+  if (a.high < b.high)
+    return -1;
+  if (a.high > b.high)
+    return 1;
+  if (a.low < b.low)
+    return -1;
+  if (a.low > b.low)
+    return 1;
+
+  return 0;
+}
+
+/* Compares two values A and B.  Returns max value.  Signedness of the
+   comparison is given by UNS.  */
+
+double_int
+double_int_max (double_int a, double_int b, bool uns)
+{
+  return (double_int_cmp (a, b, uns) == 1) ? a : b;
+}
+
+/* Compares two signed values A and B.  Returns max value.  */
+
+double_int double_int_smax (double_int a, double_int b)
+{
+  return (double_int_scmp (a, b) == 1) ? a : b;
+}
+
+/* Compares two unsigned values A and B.  Returns max value.  */
+
+double_int double_int_umax (double_int a, double_int b)
+{
+  return (double_int_ucmp (a, b) == 1) ? a : b;
+}
+
+/* Compares two values A and B.  Returns mix value.  Signedness of the
+   comparison is given by UNS.  */
+
+double_int double_int_min (double_int a, double_int b, bool uns)
+{
+  return (double_int_cmp (a, b, uns) == -1) ? a : b;
+}
+
+/* Compares two signed values A and B.  Returns min value.  */
+
+double_int double_int_smin (double_int a, double_int b)
+{
+  return (double_int_scmp (a, b) == -1) ? a : b;
+}
+
+/* Compares two unsigned values A and B.  Returns min value.  */
+
+double_int double_int_umin (double_int a, double_int b)
+{
+  return (double_int_ucmp (a, b) == -1) ? a : b;
+}
+
+/* Splits last digit of *CST (taken as unsigned) in BASE and returns it.  */
+
+static unsigned
+double_int_split_digit (double_int *cst, unsigned base)
+{
+  unsigned HOST_WIDE_INT resl, reml;
+  HOST_WIDE_INT resh, remh;
+
+  div_and_round_double (FLOOR_DIV_EXPR, true, cst->low, cst->high, base, 0,
+			&resl, &resh, &reml, &remh);
+  cst->high = resh;
+  cst->low = resl;
+
+  return reml;
+}
+
+/* Dumps CST to FILE.  If UNS is true, CST is considered to be unsigned,
+   otherwise it is signed.  */
+
+void
+dump_double_int (FILE *file, double_int cst, bool uns)
+{
+  unsigned digits[100], n;
+  int i;
+
+  if (double_int_zero_p (cst))
+    {
+      fprintf (file, "0");
+      return;
+    }
+
+  if (!uns && double_int_negative_p (cst))
+    {
+      fprintf (file, "-");
+      cst = double_int_neg (cst);
+    }
+
+  for (n = 0; !double_int_zero_p (cst); n++)
+    digits[n] = double_int_split_digit (&cst, 10);
+  for (i = n - 1; i >= 0; i--)
+    fprintf (file, "%u", digits[i]);
+}
+
+
+/* Sets RESULT to VAL, taken unsigned if UNS is true and as signed
+   otherwise.  */
+
+void
+mpz_set_double_int (mpz_t result, double_int val, bool uns)
+{
+  bool negate = false;
+  unsigned HOST_WIDE_INT vp[2];
+
+  if (!uns && double_int_negative_p (val))
+    {
+      negate = true;
+      val = double_int_neg (val);
+    }
+
+  vp[0] = val.low;
+  vp[1] = (unsigned HOST_WIDE_INT) val.high;
+  mpz_import (result, 2, -1, sizeof (HOST_WIDE_INT), 0, 0, vp);
+
+  if (negate)
+    mpz_neg (result, result);
+}
+
+/* Returns VAL converted to TYPE.  If WRAP is true, then out-of-range
+   values of VAL will be wrapped; otherwise, they will be set to the
+   appropriate minimum or maximum TYPE bound.  */
+
+double_int
+mpz_get_double_int (const_tree type, mpz_t val, bool wrap)
+{
+  unsigned HOST_WIDE_INT *vp;
+  size_t count, numb;
+  double_int res;
+
+  if (!wrap)
+    {
+      mpz_t min, max;
+
+      mpz_init (min);
+      mpz_init (max);
+      get_type_static_bounds (type, min, max);
+
+      if (mpz_cmp (val, min) < 0)
+	mpz_set (val, min);
+      else if (mpz_cmp (val, max) > 0)
+	mpz_set (val, max);
+
+      mpz_clear (min);
+      mpz_clear (max);
+    }
+
+  /* Determine the number of unsigned HOST_WIDE_INT that are required
+     for representing the value.  The code to calculate count is
+     extracted from the GMP manual, section "Integer Import and Export":
+     http://gmplib.org/manual/Integer-Import-and-Export.html  */
+  numb = 8*sizeof(HOST_WIDE_INT);
+  count = (mpz_sizeinbase (val, 2) + numb-1) / numb;
+  if (count < 2)
+    count = 2;
+  vp = (unsigned HOST_WIDE_INT *) alloca (count * sizeof(HOST_WIDE_INT));
+
+  vp[0] = 0;
+  vp[1] = 0;
+  mpz_export (vp, &count, -1, sizeof (HOST_WIDE_INT), 0, 0, val);
+
+  gcc_assert (wrap || count <= 2);
+
+  res.low = vp[0];
+  res.high = (HOST_WIDE_INT) vp[1];
+
+  res = double_int_ext (res, TYPE_PRECISION (type), TYPE_UNSIGNED (type));
+  if (mpz_sgn (val) < 0)
+    res = double_int_neg (res);
+
+  return res;
+}