Index: Objects/intobject.c
===================================================================
--- Objects/intobject.c	(revision 56970)
+++ Objects/intobject.c	(working copy)
@@ -449,10 +449,13 @@
 int_hash(PyIntObject *v)
 {
 	/* XXX If this is changed, you also need to change the way
-	   Python's long, float and complex types are hashed. */
+	   Python's long, float, complex and Decimal types are hashed. */
 	long x = v -> ob_ival;
 	if (x == -1)
 		x = -2;
+	/* next line for compatibility with long_hash */
+	if (x == LONG_MIN)
+		x = LONG_MAX;
 	return x;
 }
 
Index: Objects/longobject.c
===================================================================
--- Objects/longobject.c	(revision 56970)
+++ Objects/longobject.c	(working copy)
@@ -1922,13 +1922,16 @@
 static long
 long_hash(PyLongObject *v)
 {
-	long x;
+	unsigned long x;
+	long y;
 	Py_ssize_t i;
 	int sign;
 
 	/* This is designed so that Python ints and longs with the
 	   same value hash to the same value, otherwise comparisons
 	   of mapping keys will turn out weird */
+
+	/* The hash value is also designed to be periodic modulo ULONG_MAX */
 	i = v->ob_size;
 	sign = 1;
 	x = 0;
@@ -1941,12 +1944,22 @@
 		/* Force a native long #-bits (32 or 64) circular shift */
 		x = ((x << SHIFT) & ~MASK) | ((x >> LONG_BIT_SHIFT) & MASK);
 		x += v->ob_digit[i];
+		/* On overflow, compensate for the wraparound (= subtraction
+		   of 2**(bits_in_long)) by incrementing.  This preserves the
+		   value modulo ULONG_MAX = 2**(bits_in_long)-1. */
+		if (x < v->ob_digit[i])
+			x++;
 	}
 #undef LONG_BIT_SHIFT
-	x = x * sign;
-	if (x == -1)
-		x = -2;
-	return x;
+	if (sign == -1)
+		x = ~x;
+	if (x == ULONG_MAX)
+		x = 0;
+	/* x is now the reduction of v modulo ULONG_MAX */
+        y = (long)x;
+	if (y < -2)
+		y += 1;
+	return y;
 }
 
 
Index: Lib/decimal.py
===================================================================
--- Lib/decimal.py	(revision 56970)
+++ Lib/decimal.py	(working copy)
@@ -780,8 +780,13 @@
             if self._isnan():
                 raise TypeError('Cannot hash a NaN value.')
             return hash(str(self))
-        i = int(self)
-        if self == Decimal(i):
+        if self._isinteger():
+            # reduce value modulo 2**64-1
+            op = _WorkRep(self.to_integral())
+            m = (1<<64)-1
+            i = (op.int % m)*pow(10, op.exp, m) % m
+            if op.sign == 1:
+                i = -i
             return hash(i)
         assert self.__nonzero__()   # '-0' handled by integer case
         return hash(str(self.normalize()))
Index: Lib/test/test_hash.py
===================================================================
--- Lib/test/test_hash.py	(revision 56970)
+++ Lib/test/test_hash.py	(working copy)
@@ -18,10 +18,21 @@
 
     def test_numeric_literals(self):
         self.same_hash(1, 1L, 1.0, 1.0+0.0j)
+        self.same_hash(0, 0L, 0.0, 0.0+0.0j)
+        self.same_hash(-1, -1L, -1.0, -1.0+0.0j)
+        self.same_hash(-2, -2L, -2.0, -2.0+0.0j)
 
     def test_coerced_integers(self):
         self.same_hash(int(1), long(1), float(1), complex(1),
                        int('1'), float('1.0'))
+        self.same_hash(int(-2**31), long(-2**31), float(-2**31))
+        self.same_hash(int(1-2**31), long(1-2**31), float(1-2**31))
+        self.same_hash(int(2**31-1), long(2**31-1), float(2**31-1))
+        # for 64-bit platforms
+        self.same_hash(int(2**31), long(2**31), float(2**31))
+        self.same_hash(int(-2**63), long(-2**63), float(-2**63))
+        self.same_hash(int(1-2**63), long(1-2**63))
+        self.same_hash(int(2**63-1), long(2**63-1))
 
     def test_coerced_floats(self):
         self.same_hash(long(1.23e300), float(1.23e300))