Index: gmpy_mpz.c
===================================================================
--- gmpy_mpz.c	(revision 311)
+++ gmpy_mpz.c	(working copy)
@@ -400,72 +400,99 @@
     return result;
 }

+static int gmpy_mpz_bit_set_iterable(PyObject *self, PyObject *other) {
+  long bit_index;
+  PyObject *iterator, *item;
+
+  iterator = PyObject_GetIter(other);
+  if (!iterator) {
+    TYPE_ERROR("bit_set() failed with iterator");
+    return -1;
+  }
+
+  while ((item = PyIter_Next(iterator))) {
+
+    bit_index = clong_From_Integer(item);
+    if(bit_index == -1 && PyErr_Occurred()) {
+      TYPE_ERROR("bit_set() requires 'mpz','int' arguments");
+      goto err;
+    }
+
+    if(bit_index < 0) {
+      VALUE_ERROR("bit_index must be >= 0");
+      goto err;
+    }
+
+    mpz_setbit(Pympz_AS_MPZ(self), bit_index);
+    Py_DECREF(item);
+  }
+  Py_DECREF(iterator);
+  return 0;
+ err:
+  Py_DECREF(item);
+  Py_DECREF(iterator);
+  return -1;
+}
+
+static int gmpy_mpz_bit_setall(PyObject *self, PyObject *other) {
+    Py_ssize_t i, cur, length, start, stop, step, slicelength;
+
+    if (!PySlice_Check(other))
+      return gmpy_mpz_bit_set_iterable(self, other);
+
+    /* slice */
+    length = mpz_sizeinbase(Pympz_AS_MPZ(self), 2);
+    if (PySlice_GetIndicesEx((PySliceObject*)other, length,
+                             &start, &stop, &step, &slicelength) < 0) {
+      TYPE_ERROR("bit_set() failed with slice");
+      return -1;
+    }
+
+    for (cur = start, i = 0; i < slicelength;
+         cur += step, i++) {
+      mpz_setbit(Pympz_AS_MPZ(self), cur);
+    }
+    return 0;
+}
+
 static PyObject *
 Pympz_bit_set(PyObject *self, PyObject *other)
 {
     long bit_index;
-    PyObject *result, *iterator, *item;
-    int temp;
-    Py_ssize_t i, length, start, stop, step, slicelength;
+    PyObject *result = NULL;
+    int is_mpz = 0;

-    if((Pyxmpz_Check(self) && (PyIter_Check(other)))) {
-        iterator = PyObject_GetIter(other);
-        if(!iterator) {
-            TYPE_ERROR("bit_set() failed with iterator");
-            return NULL;
-        }
-        while((item = PyIter_Next(iterator))) {
-            bit_index = clong_From_Integer(item);
-            if(bit_index == -1 && PyErr_Occurred()) {
-                TYPE_ERROR("bit_set() requires 'mpz','int' arguments");
-                Py_DECREF(item);
-                Py_DECREF(iterator);
-                return NULL;
-            }
-            if(bit_index < 0) {
-                VALUE_ERROR("bit_index must be >= 0");
-                Py_DECREF(item);
-                Py_DECREF(iterator);
-                return NULL;
-            }
-            mpz_setbit(Pympz_AS_MPZ(self), bit_index);
-            Py_DECREF(item);
-        }
-        Py_DECREF(iterator);
-        Py_RETURN_NONE;
-    } else if((Pyxmpz_Check(self) && (PySlice_Check(other)))) {
-        length = mpz_sizeinbase(Pympz_AS_MPZ(self), 2);
-        temp = PySlice_GetIndicesEx((PySliceObject*)other, length, &start, &stop, &step, &slicelength);
-        if(temp == -1) {
-            TYPE_ERROR("bit_set() failed with slice");
-            return NULL;
-        }
-        for(i=start;i<stop;i+=step) {
-            mpz_setbit(Pympz_AS_MPZ(self), i);
-        }
-        Py_RETURN_NONE;
-    } else {
-        bit_index = clong_From_Integer(other);
-        if(bit_index == -1 && PyErr_Occurred()) {
-            TYPE_ERROR("bit_set() requires 'mpz','int' arguments");
-            return NULL;
-        }
+    if (!Pyxmpz_Check(self)) {
+      is_mpz = 1;
+      CREATE0_ONE_MPZANY(result);
+      mpz_set(Pympz_AS_MPZ(result), Pympz_AS_MPZ(self));
+      self = result;
+    }

-        if(bit_index < 0) {
-            VALUE_ERROR("bit_index must be >= 0");
-            return NULL;
-        }
+    bit_index = clong_From_Integer(other);
+    if (bit_index < 0) {
+      if (bit_index == -1 && PyErr_Occurred()) {
+        /* integer index failed */
+        PyErr_Clear();
+        if (gmpy_mpz_bit_setall(self, other) == -1)
+          goto err;
+        goto ret;
+      }
+      VALUE_ERROR("bit_index must be >= 0");
+      goto err;
+    }

-        if(Pyxmpz_Check(self)) {
-            mpz_setbit(Pympz_AS_MPZ(self), bit_index);
-            Py_RETURN_NONE;
-        } else {
-            CREATE0_ONE_MPZANY(result);
-            mpz_set(Pympz_AS_MPZ(result), Pympz_AS_MPZ(self));
-            mpz_setbit(Pympz_AS_MPZ(result), bit_index);
-            return result;
-        }
-    }
+    mpz_setbit(Pympz_AS_MPZ(self), bit_index);
+    goto ret;
+
+ err:
+    if (is_mpz)
+      Py_DECREF(result);
+    return NULL;
+ ret:
+    if (is_mpz)
+      return result; /* return new reference */
+    Py_RETURN_NONE;
 }

 static char doc_bit_flipm[]="\