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.

structtable_entry {PyTypeObject*left;PyTypeObject*left;binaryfunc*func;};TARGET(BINARY_OP_TABLE) {PyObject*lhs=SECOND();PyObject*rhs=TOP();Cache*cache=GET_CACHE();structtable_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) {        gotoerror;    }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 operationsint + int,float + float, etc. inline.

We can replaceBINARY_SUBSCR withBINARY_OP ([]) to allow effective specialization ofBINARY_SUBSCR
E.g. subscriptingarray.array[int] can be handled with the registration mechanism described below.

Registering binary functions at runtime

faster-cpython/ideas#162

Linked PRs

• gh-100239: specialize long tail of binary operations #128722
• gh-100239: specialize bitwise logical binary ops on ints #128927
• gh-100239: Specialize concatenation of lists and tuples #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