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Specialize long tail of binary operations using a table. #100239
Description
There is a desire to specialize the remaining binary operations (including binary subscript).
However adding more and more specialized instructions is likely to make performance worse.
This idea is to have a lookup table of types pairs and function pointers. This is less efficient than inlining the code, but more extensible.
A single instruction can then support up to 256 specializations.
This will only work for immutable classes.
struct table_entry {
PyTypeObject *left;
PyTypeObject *left;
binaryfunc *func;
};
TARGET(BINARY_OP_TABLE) {
PyObject *lhs = SECOND();
PyObject *rhs = TOP();
Cache *cache = GET_CACHE();
struct table_entry* entry = &THE_TABLE[cache->table_index];
DEOPT_IF(Py_TYPE(lhs) != entry->left);
DEOPT_IF(Py_TYPE(rhs) != entry->right);
PyObject *res = entry->func(lhs, rhs);
if (res == NULL) {
goto error;
}
STACK_SHRINK(1);
Py_DECREF(lhs);
Py_DECREF(rhs);
SET_TOP(res);
DISPATCH();
}An ancillary mapping of (left, right) -> index will be needed for efficient specialization.
It is probably worth keeping the most common operations int + int, float + float, etc. inline.
We can replace BINARY_SUBSCR with BINARY_OP ([]) to allow effective specialization of BINARY_SUBSCR
E.g. subscripting array.array[int] can be handled with the registration mechanism described below.
Registering binary functions at runtime
Linked PRs
- gh-100239: specialize long tail of binary operations #128722
- gh-100239: specialize bitwise logical binary ops on ints #128927
- gh-100239: Specialize binary operations using BINARY_OP_EXTEND #128956
- gh-100239: Handle NaN and zero division in guards #128963
- gh-100239: replace BINARY_SUBSCR & family by BINARY_OP with oparg NB_SUBSCR #129379
- gh-100239: specialize left and right shift ops on ints #129431
- gh-100239: replace BINARY_SUBSCR & family by BINARY_OP with oparg NB_SUBSCR #129700
- gh-100239: more refined specialisation stats for BINARY_OP/SUBSCR #132068
- gh-100239: fix bug in comparison #132093
- gh-100239: more stats for BINARY_OP/SUBSCR specialization #132230
- gh-100239: specialize dict subclasses with no getitem override #132383
- gh-100239: specialize BINARY_OP/SUBSCR for list-slice #132626
- gh-100239: use PyFloat_AS_DOUBLE and _PyLong_IsZero in the float / compactlong specializations #144826
- gh-100239: Propagate type info through _BINARY_OP_EXTEND in tier 2 #148146
- gh-100239: expose sq_repeat helpers for BINARY_OP_EXTEND #148791
- gh-100239: specialize mixed int/float inplace binary ops #149413
- gh-100239: specialize bytes binary operations #149458
- gh-100239: Specialize exact float division with BINARY_OP_EXTEND #156324
- gh-100239: specialize small integer powers (x**2, x**3) of compact ints #156918
Activity
pythongh-100239: specialize long tail of binary operations
pythongh-100239: specialize long tail of binary operations
Merge remote-tracking branch 'upstream/main' into pythongh-100239
Merge remote-tracking branch 'upstream/main' into pythongh-100239
Merge remote-tracking branch 'upstream/main' into pythongh-100239
Merge branch 'main' into pythongh-100239
gh-100239: specialize long tail of binary operations (#128722)
pythongh-100239: specialize bitwose logical binary ops
pythongh-100239: specialize bitwise logical binary ops on non-negativ…
encukou commented on Jan 17, 2025
#128722 broke repeated runs of test.test_ctypes.test_random_things.CallbackTracbackTestCase.test_FloatDivisionError, on several refleak buildbots e.g. https://buildbot.python.org/#/builders/920/builds/1287
Is it possible to fix this today?
Eclips4 commented on Jan 17, 2025
I'll take care of it!
gh-100239: Handle NaN and zero division in guards for `BINARY_OP_EXTE…
17 remaining items
gh-100239: specialize BINARY_OP/SUBSCR for list-slice (#132626)
gh-100239: Use ``PyFloat_AS_DOUBLE`` and `_PyLong_IsZero`` in the flo…
pythongh-100239: Use ``PyFloat_AS_DOUBLE`` and `_PyLong_IsZero`` in t…
pythongh-100239: Propagate type info through _BINARY_OP_EXTEND in tier 2
pythongh-100239: Propagate type info through _BINARY_OP_EXTEND in tier 2
gh-100239: Propagate type info through _BINARY_OP_EXTEND in tier 2 (G…
eendebakpt commented on Apr 15, 2026
Some additional ideas for further improvements #128956 (comment)
gh-100239: Specialize more binary operations using BINARY_OP_EXTEND (G…
pythongh-100239: expose `sq_repeat` helpers for `BINARY_OP_EXTEND`
pythongh-100239: Use ``PyFloat_AS_DOUBLE`` and `_PyLong_IsZero`` in t…
pythongh-100239: Propagate type info through _BINARY_OP_EXTEND in tie…
pythongh-100239: Specialize more binary operations using BINARY_OP_EX…
gh-100239: specialize mixed int/float inplace binary ops (GH-149413)
Merge branch 'main' into pythongh-100239/expose-sq-repeat-helpers
gh-100239: expose `sq_repeat` helpers for `BINARY_OP_EXTEND` (#148791)