diff gcc/double-int.c @ 16:04ced10e8804

gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
parents f6334be47118
children 84e7813d76e9
line wrap: on
line diff
--- a/gcc/double-int.c	Sun Aug 21 07:07:55 2011 +0900
+++ b/gcc/double-int.c	Fri Oct 27 22:46:09 2017 +0900
@@ -1,5 +1,5 @@
 /* Operations with long integers.
-   Copyright (C) 2006, 2007, 2009, 2010 Free Software Foundation, Inc.
+   Copyright (C) 2006-2017 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -20,9 +20,35 @@
 #include "config.h"
 #include "system.h"
 #include "coretypes.h"
-#include "tm.h"			/* For SHIFT_COUNT_TRUNCATED.  */
+#include "tm.h"			/* For BITS_PER_UNIT and *_BIG_ENDIAN.  */
 #include "tree.h"
 
+static int add_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
+				 unsigned HOST_WIDE_INT, HOST_WIDE_INT,
+				 unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
+				 bool);
+
+#define add_double(l1,h1,l2,h2,lv,hv) \
+  add_double_with_sign (l1, h1, l2, h2, lv, hv, false)
+
+static int neg_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
+		       unsigned HOST_WIDE_INT *, HOST_WIDE_INT *);
+
+static int mul_double_wide_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
+				      unsigned HOST_WIDE_INT, HOST_WIDE_INT,
+				      unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
+				      unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
+				      bool);
+
+#define mul_double(l1,h1,l2,h2,lv,hv) \
+  mul_double_wide_with_sign (l1, h1, l2, h2, lv, hv, NULL, NULL, false)
+
+static int div_and_round_double (unsigned, int, unsigned HOST_WIDE_INT,
+				 HOST_WIDE_INT, unsigned HOST_WIDE_INT,
+				 HOST_WIDE_INT, unsigned HOST_WIDE_INT *,
+				 HOST_WIDE_INT *, unsigned HOST_WIDE_INT *,
+				 HOST_WIDE_INT *);
+
 /* 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
@@ -39,10 +65,10 @@
    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))
+  ((x) & ((HOST_WIDE_INT_1U << (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)
+#define BASE (HOST_WIDE_INT_1U << 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.
@@ -75,7 +101,7 @@
    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
+static 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,
@@ -105,14 +131,14 @@
    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
+static 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;
+      *hv = - (unsigned HOST_WIDE_INT) h1;
       return (*hv & h1) < 0;
     }
   else
@@ -123,25 +149,28 @@
     }
 }
 
-/* Multiply two doubleword integers with doubleword result.
+/* Multiply two doubleword integers with quadword 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.  */
+   The value is stored as four `HOST_WIDE_INT' pieces in *LV and *HV,
+   *LW and *HW.
+   If lw is NULL then only the low part and no overflow is computed.  */
 
-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)
+static int
+mul_double_wide_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,
+			   unsigned HOST_WIDE_INT *lw, HOST_WIDE_INT *hw,
+			   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;
+  unsigned HOST_WIDE_INT neglow;
+  HOST_WIDE_INT neghigh;
 
   encode (arg1, l1, h1);
   encode (arg2, l2, h2);
@@ -155,7 +184,7 @@
 	{
 	  k = i + j;
 	  /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000.  */
-	  carry += arg1[i] * arg2[j];
+	  carry += (unsigned HOST_WIDE_INT) arg1[i] * arg2[j];
 	  /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF.  */
 	  carry += prod[k];
 	  prod[k] = LOWPART (carry);
@@ -165,25 +194,89 @@
     }
 
   decode (prod, lv, hv);
-  decode (prod + 4, &toplow, &tophigh);
+
+  /* We are not interested in the wide part nor in overflow.  */
+  if (lw == NULL)
+    return 0;
+
+  decode (prod + 4, lw, hw);
 
   /* Unsigned overflow is immediate.  */
   if (unsigned_p)
-    return (toplow | tophigh) != 0;
+    return (*lw | *hw) != 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);
+      add_double (neglow, neghigh, *lw, *hw, lw, hw);
     }
   if (h2 < 0)
     {
       neg_double (l1, h1, &neglow, &neghigh);
-      add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
+      add_double (neglow, neghigh, *lw, *hw, lw, hw);
+    }
+  return (*hv < 0 ? ~(*lw & *hw) : *lw | *hw) != 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 (count >= HOST_BITS_PER_DOUBLE_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;
     }
-  return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 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) >= HOST_BITS_PER_DOUBLE_INT)
+    ;
+  else if ((prec - count) >= HOST_BITS_PER_WIDE_INT)
+    {
+      *hv &= ~(HOST_WIDE_INT_M1U << (prec - count - HOST_BITS_PER_WIDE_INT));
+      *hv |= signmask << (prec - count - HOST_BITS_PER_WIDE_INT);
+    }
+  else
+    {
+      *hv = signmask;
+      *lv &= ~(HOST_WIDE_INT_M1U << (prec - count));
+      *lv |= signmask << (prec - count);
+    }
 }
 
 /* Shift the doubleword integer in L1, H1 left by COUNT places
@@ -192,23 +285,14 @@
    ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
    Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV.  */
 
-void
+static 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 count, unsigned int prec,
+	       unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv)
 {
   unsigned HOST_WIDE_INT signmask;
 
-  if (count < 0)
-    {
-      rshift_double (l1, h1, -count, prec, lv, hv, arith);
-      return;
-    }
-
-  if (SHIFT_COUNT_TRUNCATED)
-    count %= prec;
-
-  if (count >= 2 * HOST_BITS_PER_WIDE_INT)
+  if (count >= HOST_BITS_PER_DOUBLE_INT)
     {
       /* Shifting by the host word size is undefined according to the
 	 ANSI standard, so we must handle this as a special case.  */
@@ -234,89 +318,21 @@
 		   >> (prec - HOST_BITS_PER_WIDE_INT - 1))
 		: (*lv >> (prec - 1))) & 1);
 
-  if (prec >= 2 * HOST_BITS_PER_WIDE_INT)
+  if (prec >= HOST_BITS_PER_DOUBLE_INT)
     ;
   else if (prec >= HOST_BITS_PER_WIDE_INT)
     {
-      *hv &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
+      *hv &= ~(HOST_WIDE_INT_M1U << (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 &= ~(HOST_WIDE_INT_M1U << prec);
       *lv |= signmask << prec;
     }
 }
 
-/* Shift the doubleword integer in L1, H1 right by COUNT places
-   keeping only PREC bits of result.  Shift left 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
-rshift_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)
-    {
-      lshift_double (l1, h1, -count, prec, lv, hv, arith);
-      return;
-    }
-
-  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 >= (HOST_WIDE_INT)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);
-    }
-}
-
 /* 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
@@ -326,7 +342,7 @@
    Return nonzero if the operation overflows.
    UNS nonzero says do unsigned division.  */
 
-int
+static int
 div_and_round_double (unsigned code, int uns,
 		      /* num == numerator == dividend */
 		      unsigned HOST_WIDE_INT lnum_orig,
@@ -530,7 +546,7 @@
       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,
+	  add_double (*lquo, *hquo, HOST_WIDE_INT_M1, HOST_WIDE_INT_M1,
 		      lquo, hquo);
 	}
       else
@@ -541,7 +557,7 @@
     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,
+	  add_double (*lquo, *hquo, HOST_WIDE_INT_1, HOST_WIDE_INT_0,
 		      lquo, hquo);
 	}
       else
@@ -553,32 +569,31 @@
       {
 	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;
+	unsigned HOST_WIDE_INT labs_den = lden, lnegabs_rem, ldiff;
+	HOST_WIDE_INT habs_den = hden, hnegabs_rem, hdiff;
 
 	/* Get absolute values.  */
-	if (*hrem < 0)
+	if (!uns && *hrem < 0)
 	  neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
-	if (hden < 0)
+	if (!uns && 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 abs(rem) >= abs(den) - abs(rem), adjust the quotient.  */
+	neg_double (labs_rem, habs_rem, &lnegabs_rem, &hnegabs_rem);
+	add_double (labs_den, habs_den, lnegabs_rem, hnegabs_rem,
+		    &ldiff, &hdiff);
 
-	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 (((unsigned HOST_WIDE_INT) habs_rem
+	     > (unsigned HOST_WIDE_INT) hdiff)
+	    || (habs_rem == hdiff && labs_rem >= ldiff))
 	  {
-	    if (*hquo < 0)
+	    if (quo_neg)
 	      /* quo = quo - 1;  */
 	      add_double (*lquo, *hquo,
-			  (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
+			  HOST_WIDE_INT_M1, HOST_WIDE_INT_M1, lquo, hquo);
 	    else
 	      /* quo = quo + 1; */
-	      add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
+	      add_double (*lquo, *hquo, HOST_WIDE_INT_1, HOST_WIDE_INT_0,
 			  lquo, hquo);
 	  }
 	else
@@ -598,10 +613,57 @@
 }
 
 
+/* Construct from a buffer of length LEN.  BUFFER will be read according
+   to byte endianness and word endianness.  Only the lower LEN bytes
+   of the result are set; the remaining high bytes are cleared.  */
+
+double_int
+double_int::from_buffer (const unsigned char *buffer, int len)
+{
+  double_int result = double_int_zero;
+  int words = len / UNITS_PER_WORD;
+
+  gcc_assert (len * BITS_PER_UNIT <= HOST_BITS_PER_DOUBLE_INT);
+
+  for (int byte = 0; byte < len; byte++)
+    {
+      int offset;
+      int bitpos = byte * BITS_PER_UNIT;
+      unsigned HOST_WIDE_INT value;
+
+      if (len > UNITS_PER_WORD)
+	{
+	  int word = byte / UNITS_PER_WORD;
+
+	  if (WORDS_BIG_ENDIAN)
+	    word = (words - 1) - word;
+
+	  offset = word * UNITS_PER_WORD;
+
+	  if (BYTES_BIG_ENDIAN)
+	    offset += (UNITS_PER_WORD - 1) - (byte % UNITS_PER_WORD);
+	  else
+	    offset += byte % UNITS_PER_WORD;
+	}
+      else
+	offset = BYTES_BIG_ENDIAN ? (len - 1) - byte : byte;
+
+      value = (unsigned HOST_WIDE_INT) buffer[offset];
+
+      if (bitpos < HOST_BITS_PER_WIDE_INT)
+	result.low |= value << bitpos;
+      else
+	result.high |= value << (bitpos - HOST_BITS_PER_WIDE_INT);
+    }
+
+  return result;
+}
+
+
 /* Returns mask for PREC bits.  */
 
 double_int
-double_int_mask (unsigned prec)
+double_int::mask (unsigned prec)
 {
   unsigned HOST_WIDE_INT m;
   double_int mask;
@@ -616,12 +678,32 @@
   else
     {
       mask.high = 0;
-      mask.low = ((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1;
+      mask.low = prec ? ((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1 : 0;
     }
 
   return mask;
 }
 
+/* Returns a maximum value for signed or unsigned integer
+   of precision PREC.  */
+
+double_int
+double_int::max_value (unsigned int prec, bool uns)
+{
+  return double_int::mask (prec - (uns ? 0 : 1));
+}
+
+/* Returns a minimum value for signed or unsigned integer
+   of precision PREC.  */
+
+double_int
+double_int::min_value (unsigned int prec, bool uns)
+{
+  if (uns)
+    return double_int_zero;
+  return double_int_one.lshift (prec - 1, prec, false);
+}
+
 /* 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.
@@ -630,20 +712,21 @@
    of CST, with the given signedness.  */
 
 double_int
-double_int_ext (double_int cst, unsigned prec, bool uns)
+double_int::ext (unsigned prec, bool uns) const
 {
   if (uns)
-    return double_int_zext (cst, prec);
+    return this->zext (prec);
   else
-    return double_int_sext (cst, prec);
+    return this->sext (prec);
 }
 
-/* The same as double_int_ext with UNS = true.  */
+/* The same as double_int::ext with UNS = true.  */
 
 double_int
-double_int_zext (double_int cst, unsigned prec)
+double_int::zext (unsigned prec) const
 {
-  double_int mask = double_int_mask (prec);
+  const double_int &cst = *this;
+  double_int mask = double_int::mask (prec);
   double_int r;
 
   r.low = cst.low & mask.low;
@@ -652,12 +735,13 @@
   return r;
 }
 
-/* The same as double_int_ext with UNS = false.  */
+/* The same as double_int::ext with UNS = false.  */
 
 double_int
-double_int_sext (double_int cst, unsigned prec)
+double_int::sext (unsigned prec) const
 {
-  double_int mask = double_int_mask (prec);
+  const double_int &cst = *this;
+  double_int mask = double_int::mask (prec);
   double_int r;
   unsigned HOST_WIDE_INT snum;
 
@@ -685,8 +769,9 @@
 /* Returns true if CST fits in signed HOST_WIDE_INT.  */
 
 bool
-double_int_fits_in_shwi_p (double_int cst)
+double_int::fits_shwi () const
 {
+  const double_int &cst = *this;
   if (cst.high == 0)
     return (HOST_WIDE_INT) cst.low >= 0;
   else if (cst.high == -1)
@@ -699,65 +784,147 @@
    unsigned HOST_WIDE_INT if UNS is true.  */
 
 bool
-double_int_fits_in_hwi_p (double_int cst, bool uns)
+double_int::fits_hwi (bool uns) const
 {
   if (uns)
-    return double_int_fits_in_uhwi_p (cst);
+    return this->fits_uhwi ();
   else
-    return double_int_fits_in_shwi_p (cst);
+    return this->fits_shwi ();
 }
 
 /* Returns A * B.  */
 
 double_int
-double_int_mul (double_int a, double_int b)
+double_int::operator * (double_int b) const
 {
+  const double_int &a = *this;
   double_int ret;
   mul_double (a.low, a.high, b.low, b.high, &ret.low, &ret.high);
   return ret;
 }
 
+/* Multiplies *this with B and returns a reference to *this.  */
+
+double_int &
+double_int::operator *= (double_int b)
+{
+  mul_double (low, high, b.low, b.high, &low, &high);
+  return *this;
+}
+
 /* 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::mul_with_sign (double_int b, bool unsigned_p, bool *overflow) const
 {
-  double_int ret;
-  *overflow = mul_double_with_sign (a.low, a.high, b.low, b.high,
-                                    &ret.low, &ret.high, unsigned_p);
+  const double_int &a = *this;
+  double_int ret, tem;
+  *overflow = mul_double_wide_with_sign (a.low, a.high, b.low, b.high,
+					 &ret.low, &ret.high,
+					 &tem.low, &tem.high, unsigned_p);
   return ret;
 }
 
+double_int
+double_int::wide_mul_with_sign (double_int b, bool unsigned_p,
+				double_int *higher, bool *overflow) const
+
+{
+  double_int lower;
+  *overflow = mul_double_wide_with_sign (low, high, b.low, b.high,
+					 &lower.low, &lower.high,
+					 &higher->low, &higher->high,
+					 unsigned_p);
+  return lower;
+}
+
 /* Returns A + B.  */
 
 double_int
-double_int_add (double_int a, double_int b)
+double_int::operator + (double_int b) const
 {
+  const double_int &a = *this;
   double_int ret;
   add_double (a.low, a.high, b.low, b.high, &ret.low, &ret.high);
   return ret;
 }
 
+/* Adds B to *this and returns a reference to *this.  */
+
+double_int &
+double_int::operator += (double_int b)
+{
+  add_double (low, high, b.low, b.high, &low, &high);
+  return *this;
+}
+
+
+/* Returns A + B. If the operation overflows according to UNSIGNED_P,
+   *OVERFLOW is set to nonzero.  */
+
+double_int
+double_int::add_with_sign (double_int b, bool unsigned_p, bool *overflow) const
+{
+  const double_int &a = *this;
+  double_int ret;
+  *overflow = add_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_sub (double_int a, double_int b)
+double_int::operator - (double_int b) const
 {
+  const double_int &a = *this;
   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;
 }
 
+/* Subtracts B from *this and returns a reference to *this.  */
+
+double_int &
+double_int::operator -= (double_int b)
+{
+  neg_double (b.low, b.high, &b.low, &b.high);
+  add_double (low, high, b.low, b.high, &low, &high);
+  return *this;
+}
+
+
+/* Returns A - B. If the operation overflows via inconsistent sign bits,
+   *OVERFLOW is set to nonzero.  */
+
+double_int
+double_int::sub_with_overflow (double_int b, bool *overflow) const
+{
+  double_int ret;
+  neg_double (b.low, b.high, &ret.low, &ret.high);
+  add_double (low, high, ret.low, ret.high, &ret.low, &ret.high);
+  *overflow = OVERFLOW_SUM_SIGN (ret.high, b.high, high);
+  return ret;
+}
+
 /* Returns -A.  */
 
 double_int
-double_int_neg (double_int a)
+double_int::operator - () const
+{
+  const double_int &a = *this;
+  double_int ret;
+  neg_double (a.low, a.high, &ret.low, &ret.high);
+  return ret;
+}
+
+double_int
+double_int::neg_with_overflow (bool *overflow) const
 {
   double_int ret;
-  neg_double (a.low, a.high, &ret.low, &ret.high);
+  *overflow = neg_double (low, high, &ret.low, &ret.high);
   return ret;
 }
 
@@ -767,9 +934,23 @@
    stored to MOD.  */
 
 double_int
-double_int_divmod (double_int a, double_int b, bool uns, unsigned code,
-		   double_int *mod)
+double_int::divmod_with_overflow (double_int b, bool uns, unsigned code,
+				  double_int *mod, bool *overflow) const
 {
+  const double_int &a = *this;
+  double_int ret;
+
+  *overflow = div_and_round_double (code, uns, a.low, a.high,
+				    b.low, b.high, &ret.low, &ret.high,
+				    &mod->low, &mod->high);
+  return ret;
+}
+
+double_int
+double_int::divmod (double_int b, bool uns, unsigned code,
+		    double_int *mod) const
+{
+  const double_int &a = *this;
   double_int ret;
 
   div_and_round_double (code, uns, a.low, a.high,
@@ -778,20 +959,20 @@
   return ret;
 }
 
-/* The same as double_int_divmod with UNS = false.  */
+/* 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)
+double_int::sdivmod (double_int b, unsigned code, double_int *mod) const
 {
-  return double_int_divmod (a, b, false, code, mod);
+  return this->divmod (b, false, code, mod);
 }
 
-/* The same as double_int_divmod with UNS = true.  */
+/* 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)
+double_int::udivmod (double_int b, unsigned code, double_int *mod) const
 {
-  return double_int_divmod (a, b, true, code, mod);
+  return this->divmod (b, true, code, mod);
 }
 
 /* Returns A / B (computed as unsigned depending on UNS, and rounded as
@@ -799,27 +980,27 @@
    must be included before tree.h.  */
 
 double_int
-double_int_div (double_int a, double_int b, bool uns, unsigned code)
+double_int::div (double_int b, bool uns, unsigned code) const
 {
   double_int mod;
 
-  return double_int_divmod (a, b, uns, code, &mod);
+  return this->divmod (b, uns, code, &mod);
 }
 
-/* The same as double_int_div with UNS = false.  */
+/* The same as double_int::div with UNS = false.  */
 
 double_int
-double_int_sdiv (double_int a, double_int b, unsigned code)
+double_int::sdiv (double_int b, unsigned code) const
 {
-  return double_int_div (a, b, false, code);
+  return this->div (b, false, code);
 }
 
-/* The same as double_int_div with UNS = true.  */
+/* The same as double_int::div with UNS = true.  */
 
 double_int
-double_int_udiv (double_int a, double_int b, unsigned code)
+double_int::udiv (double_int b, unsigned code) const
 {
-  return double_int_div (a, b, true, code);
+  return this->div (b, true, code);
 }
 
 /* Returns A % B (computed as unsigned depending on UNS, and rounded as
@@ -827,46 +1008,68 @@
    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 b, bool uns, unsigned code) const
 {
   double_int mod;
 
-  double_int_divmod (a, b, uns, code, &mod);
+  this->divmod (b, uns, code, &mod);
   return mod;
 }
 
-/* The same as double_int_mod with UNS = false.  */
+/* The same as double_int::mod with UNS = false.  */
+
+double_int
+double_int::smod (double_int b, unsigned code) const
+{
+  return this->mod (b, false, code);
+}
+
+/* The same as double_int::mod with UNS = true.  */
 
 double_int
-double_int_smod (double_int a, double_int b, unsigned code)
+double_int::umod (double_int b, unsigned code) const
 {
-  return double_int_mod (a, b, false, code);
+  return this->mod (b, true, code);
 }
 
-/* The same as double_int_mod with UNS = true.  */
+/* Return TRUE iff PRODUCT is an integral multiple of FACTOR, and return
+   the multiple in *MULTIPLE.  Otherwise return FALSE and leave *MULTIPLE
+   unchanged.  */
 
-double_int
-double_int_umod (double_int a, double_int b, unsigned code)
+bool
+double_int::multiple_of (double_int factor,
+			 bool unsigned_p, double_int *multiple) const
 {
-  return double_int_mod (a, b, true, code);
+  double_int remainder;
+  double_int quotient = this->divmod (factor, unsigned_p,
+					   TRUNC_DIV_EXPR, &remainder);
+  if (remainder.is_zero ())
+    {
+      *multiple = quotient;
+      return true;
+    }
+
+  return false;
 }
 
 /* Set BITPOS bit in A.  */
 double_int
-double_int_setbit (double_int a, unsigned bitpos)
+double_int::set_bit (unsigned bitpos) const
 {
+  double_int a = *this;
   if (bitpos < HOST_BITS_PER_WIDE_INT)
-    a.low |= (unsigned HOST_WIDE_INT) 1 << bitpos;
+    a.low |= HOST_WIDE_INT_1U << bitpos;
   else
-    a.high |= (HOST_WIDE_INT) 1 <<  (bitpos - HOST_BITS_PER_WIDE_INT);
+    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)
+double_int::trailing_zeros () const
 {
+  const double_int &a = *this;
   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)
@@ -875,35 +1078,161 @@
   return bits;
 }
 
+/* Shift A left by COUNT places.  */
+
+double_int
+double_int::lshift (HOST_WIDE_INT count) const
+{
+  double_int ret;
+
+  gcc_checking_assert (count >= 0);
+
+  if (count >= HOST_BITS_PER_DOUBLE_INT)
+    {
+      /* Shifting by the host word size is undefined according to the
+	 ANSI standard, so we must handle this as a special case.  */
+      ret.high = 0;
+      ret.low = 0;
+    }
+  else if (count >= HOST_BITS_PER_WIDE_INT)
+    {
+      ret.high = low << (count - HOST_BITS_PER_WIDE_INT);
+      ret.low = 0;
+    }
+  else
+    {
+      ret.high = (((unsigned HOST_WIDE_INT) high << count)
+	     | (low >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
+      ret.low = low << count;
+    }
+
+  return ret;
+}
+
+/* Shift A right by COUNT places.  */
+
+double_int
+double_int::rshift (HOST_WIDE_INT count) const
+{
+  double_int ret;
+
+  gcc_checking_assert (count >= 0);
+
+  if (count >= HOST_BITS_PER_DOUBLE_INT)
+    {
+      /* Shifting by the host word size is undefined according to the
+	 ANSI standard, so we must handle this as a special case.  */
+      ret.high = 0;
+      ret.low = 0;
+    }
+  else if (count >= HOST_BITS_PER_WIDE_INT)
+    {
+      ret.high = 0;
+      ret.low
+	= (unsigned HOST_WIDE_INT) (high >> (count - HOST_BITS_PER_WIDE_INT));
+    }
+  else
+    {
+      ret.high = high >> count;
+      ret.low = ((low >> count)
+		 | ((unsigned HOST_WIDE_INT) high
+		    << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
+    }
+
+  return ret;
+}
+
 /* 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::lshift (HOST_WIDE_INT count, unsigned int prec, bool arith) const
 {
   double_int ret;
-  lshift_double (a.low, a.high, count, prec, &ret.low, &ret.high, arith);
+  if (count > 0)
+    lshift_double (low, high, count, prec, &ret.low, &ret.high);
+  else
+    rshift_double (low, high, absu_hwi (count), prec, &ret.low, &ret.high, arith);
   return ret;
 }
 
-/* Shift A rigth by COUNT places keeping only PREC bits of result.  Shift
+/* Shift A right 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::rshift (HOST_WIDE_INT count, unsigned int prec, bool arith) const
 {
   double_int ret;
-  rshift_double (a.low, a.high, count, prec, &ret.low, &ret.high, arith);
+  if (count > 0)
+    rshift_double (low, high, count, prec, &ret.low, &ret.high, arith);
+  else
+    lshift_double (low, high, absu_hwi (count), prec, &ret.low, &ret.high);
   return ret;
 }
 
+/* Arithmetic shift A left by COUNT places keeping only PREC bits of result.
+   Shift right if COUNT is negative.  */
+
+double_int
+double_int::alshift (HOST_WIDE_INT count, unsigned int prec) const
+{
+  double_int r;
+  if (count > 0)
+    lshift_double (low, high, count, prec, &r.low, &r.high);
+  else
+    rshift_double (low, high, absu_hwi (count), prec, &r.low, &r.high, true);
+  return r;
+}
+
+/* Arithmetic shift A right by COUNT places keeping only PREC bits of result.
+   Shift left if COUNT is negative.  */
+
+double_int
+double_int::arshift (HOST_WIDE_INT count, unsigned int prec) const
+{
+  double_int r;
+  if (count > 0)
+    rshift_double (low, high, count, prec, &r.low, &r.high, true);
+  else
+    lshift_double (low, high, absu_hwi (count), prec, &r.low, &r.high);
+  return r;
+}
+
+/* Logical shift A left by COUNT places keeping only PREC bits of result.
+   Shift right if COUNT is negative.  */
+
+double_int
+double_int::llshift (HOST_WIDE_INT count, unsigned int prec) const
+{
+  double_int r;
+  if (count > 0)
+    lshift_double (low, high, count, prec, &r.low, &r.high);
+  else
+    rshift_double (low, high, absu_hwi (count), prec, &r.low, &r.high, false);
+  return r;
+}
+
+/* Logical shift A right by COUNT places keeping only PREC bits of result.
+   Shift left if COUNT is negative.  */
+
+double_int
+double_int::lrshift (HOST_WIDE_INT count, unsigned int prec) const
+{
+  double_int r;
+  if (count > 0)
+    rshift_double (low, high, count, prec, &r.low, &r.high, false);
+  else
+    lshift_double (low, high, absu_hwi (count), prec, &r.low, &r.high);
+  return r;
+}
+
 /* 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::lrotate (HOST_WIDE_INT count, unsigned int prec) const
 {
   double_int t1, t2;
 
@@ -911,17 +1240,17 @@
   if (count < 0)
     count += prec;
 
-  t1 = double_int_lshift (a, count, prec, false);
-  t2 = double_int_rshift (a, prec - count, prec, false);
+  t1 = this->llshift (count, prec);
+  t2 = this->lrshift (prec - count, prec);
 
-  return double_int_ior (t1, t2);
+  return 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::rrotate (HOST_WIDE_INT count, unsigned int prec) const
 {
   double_int t1, t2;
 
@@ -929,30 +1258,31 @@
   if (count < 0)
     count += prec;
 
-  t1 = double_int_rshift (a, count, prec, false);
-  t2 = double_int_lshift (a, prec - count, prec, false);
+  t1 = this->lrshift (count, prec);
+  t2 = this->llshift (prec - count, prec);
 
-  return double_int_ior (t1, t2);
+  return 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)
+double_int::cmp (double_int b, bool uns) const
 {
   if (uns)
-    return double_int_ucmp (a, b);
+    return this->ucmp (b);
   else
-    return double_int_scmp (a, b);
+    return this->scmp (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)
+double_int::ucmp (double_int b) const
 {
+  const double_int &a = *this;
   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)
@@ -969,8 +1299,9 @@
    and 1 if A > B.  */
 
 int
-double_int_scmp (double_int a, double_int b)
+double_int::scmp (double_int b) const
 {
+  const double_int &a = *this;
   if (a.high < b.high)
     return -1;
   if (a.high > b.high)
@@ -983,49 +1314,139 @@
   return 0;
 }
 
+/* Compares two unsigned values A and B for less-than.  */
+
+bool
+double_int::ult (double_int b) const
+{
+  if ((unsigned HOST_WIDE_INT) high < (unsigned HOST_WIDE_INT) b.high)
+    return true;
+  if ((unsigned HOST_WIDE_INT) high > (unsigned HOST_WIDE_INT) b.high)
+    return false;
+  if (low < b.low)
+    return true;
+  return false;
+}
+
+/* Compares two unsigned values A and B for less-than or equal-to.  */
+
+bool
+double_int::ule (double_int b) const
+{
+  if ((unsigned HOST_WIDE_INT) high < (unsigned HOST_WIDE_INT) b.high)
+    return true;
+  if ((unsigned HOST_WIDE_INT) high > (unsigned HOST_WIDE_INT) b.high)
+    return false;
+  if (low <= b.low)
+    return true;
+  return false;
+}
+
+/* Compares two unsigned values A and B for greater-than.  */
+
+bool
+double_int::ugt (double_int b) const
+{
+  if ((unsigned HOST_WIDE_INT) high > (unsigned HOST_WIDE_INT) b.high)
+    return true;
+  if ((unsigned HOST_WIDE_INT) high < (unsigned HOST_WIDE_INT) b.high)
+    return false;
+  if (low > b.low)
+    return true;
+  return false;
+}
+
+/* Compares two signed values A and B for less-than.  */
+
+bool
+double_int::slt (double_int b) const
+{
+  if (high < b.high)
+    return true;
+  if (high > b.high)
+    return false;
+  if (low < b.low)
+    return true;
+  return false;
+}
+
+/* Compares two signed values A and B for less-than or equal-to.  */
+
+bool
+double_int::sle (double_int b) const
+{
+  if (high < b.high)
+    return true;
+  if (high > b.high)
+    return false;
+  if (low <= b.low)
+    return true;
+  return false;
+}
+
+/* Compares two signed values A and B for greater-than.  */
+
+bool
+double_int::sgt (double_int b) const
+{
+  if (high > b.high)
+    return true;
+  if (high < b.high)
+    return false;
+  if (low > b.low)
+    return true;
+  return false;
+}
+
+
 /* 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)
+double_int::max (double_int b, bool uns)
 {
-  return (double_int_cmp (a, b, uns) == 1) ? a : b;
+  return (this->cmp (b, uns) == 1) ? *this : b;
 }
 
 /* Compares two signed values A and B.  Returns max value.  */
 
-double_int double_int_smax (double_int a, double_int b)
+double_int
+double_int::smax (double_int b)
 {
-  return (double_int_scmp (a, b) == 1) ? a : b;
+  return (this->scmp (b) == 1) ? *this : b;
 }
 
 /* Compares two unsigned values A and B.  Returns max value.  */
 
-double_int double_int_umax (double_int a, double_int b)
+double_int
+double_int::umax (double_int b)
 {
-  return (double_int_ucmp (a, b) == 1) ? a : b;
+  return (this->ucmp (b) == 1) ? *this : 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)
+double_int
+double_int::min (double_int b, bool uns)
 {
-  return (double_int_cmp (a, b, uns) == -1) ? a : b;
+  return (this->cmp (b, uns) == -1) ? *this : b;
 }
 
 /* Compares two signed values A and B.  Returns min value.  */
 
-double_int double_int_smin (double_int a, double_int b)
+double_int
+double_int::smin (double_int b)
 {
-  return (double_int_scmp (a, b) == -1) ? a : b;
+  return (this->scmp (b) == -1) ? *this : b;
 }
 
 /* Compares two unsigned values A and B.  Returns min value.  */
 
-double_int double_int_umin (double_int a, double_int b)
+double_int
+double_int::umin (double_int b)
 {
-  return (double_int_ucmp (a, b) == -1) ? a : b;
+  return (this->ucmp (b) == -1) ? *this : b;
 }
 
 /* Splits last digit of *CST (taken as unsigned) in BASE and returns it.  */
@@ -1053,19 +1474,19 @@
   unsigned digits[100], n;
   int i;
 
-  if (double_int_zero_p (cst))
+  if (cst.is_zero ())
     {
       fprintf (file, "0");
       return;
     }
 
-  if (!uns && double_int_negative_p (cst))
+  if (!uns && cst.is_negative ())
     {
       fprintf (file, "-");
-      cst = double_int_neg (cst);
+      cst = -cst;
     }
 
-  for (n = 0; !double_int_zero_p (cst); n++)
+  for (n = 0; !cst.is_zero (); n++)
     digits[n] = double_int_split_digit (&cst, 10);
   for (i = n - 1; i >= 0; i--)
     fprintf (file, "%u", digits[i]);
@@ -1081,10 +1502,10 @@
   bool negate = false;
   unsigned HOST_WIDE_INT vp[2];
 
-  if (!uns && double_int_negative_p (val))
+  if (!uns && val.is_negative ())
     {
       negate = true;
-      val = double_int_neg (val);
+      val = -val;
     }
 
   vp[0] = val.low;
@@ -1127,11 +1548,11 @@
      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);
+  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 = (unsigned HOST_WIDE_INT *) alloca (count * sizeof (HOST_WIDE_INT));
 
   vp[0] = 0;
   vp[1] = 0;
@@ -1142,9 +1563,9 @@
   res.low = vp[0];
   res.high = (HOST_WIDE_INT) vp[1];
 
-  res = double_int_ext (res, TYPE_PRECISION (type), TYPE_UNSIGNED (type));
+  res = res.ext (TYPE_PRECISION (type), TYPE_UNSIGNED (type));
   if (mpz_sgn (val) < 0)
-    res = double_int_neg (res);
+    res = -res;
 
   return res;
 }