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Restore dicts' tp_compare slot, and change dict_richcompare to say it 

doesn't know how to do LE, LT, GE, GT.  dict_richcompare can't do the
latter any faster than dict_compare can.  More importantly, for
cmp(dict1, dict2), Python *first* tries rich compares with EQ, LT, and
GT one at a time, even if the tp_compare slot is defined, and
dict_richcompare called dict_compare for the latter two because
it couldn't do them itself.  The result was a lot of wasted calls to
dict_compare.  Now dict_richcompare gives up at once the times Python
calls it with LT and GT from try_rich_to_3way_compare(), and dict_compare
is called only once (when Python gets around to trying the tp_compare
slot).
Continued mystery:  despite that this cut the number of calls to
dict_compare approximately in half in test_mutants.py, the latter still
runs amazingly slowly.  Running under the debugger doesn't show excessive
activity in the dict comparison code anymore, so I'm guessing the culprit
is somewhere else -- but where?  Perhaps in the element (key/value)
comparison code?  We clearly spend a lot of time figuring out how to
compare things.
This commit is contained in:
Tim Peters 2001-05-10 21:45:19 +00:00
parent 4c02fecf9c
commit 4fa58bfac2
1 changed files with 3 additions and 15 deletions
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18
Objects/dictobject.c
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@ -1160,20 +1160,8 @@ dict_richcompare(PyObject *v, PyObject *w, int op)
return NULL;
res = (cmp == (op == Py_EQ)) ? Py_True : Py_False;
}
else {
cmp = dict_compare((dictobject *)v, (dictobject *)w);
if (cmp < 0 && PyErr_Occurred())
return NULL;
switch (op) {
case Py_LT: cmp = cmp < 0; break;
case Py_LE: cmp = cmp <= 0; break;
case Py_GT: cmp = cmp > 0; break;
case Py_GE: cmp = cmp >= 0; break;
default:
assert(!"op unexpected");
}
res = cmp ? Py_True : Py_False;
}
else
res = Py_NotImplemented;
Py_INCREF(res);
return res;
}
@ -1541,7 +1529,7 @@ PyTypeObject PyDict_Type = {
(printfunc)dict_print, /* tp_print */
(getattrfunc)dict_getattr, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
(cmpfunc)dict_compare, /* tp_compare */
(reprfunc)dict_repr, /* tp_repr */
0, /* tp_as_number */
&dict_as_sequence, /* tp_as_sequence */