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Fold PUSH_NULL; LOAD_CONST None into GET_AWAITABLE and GET_ANEXT #161875
Description
Feature or enhancement
Since gh-145667, SEND takes (receiver, null_or_index, value). As a result, every await and every
async for iteration compiles to:
GET_AWAITABLE / GET_ANEXT
PUSH_NULL
LOAD_COMMON_CONSTANT 7 (None)
SEND
Both opcodes are only ever emitted immediately before this pair. I propose that they push the NULL and
the None themselves:
GET_AWAITABLE:(iterable -- iter, null, none)GET_ANEXT:(aiter -- aiter, awaitable, null, none)
This saves two dispatches per await and per async for step. Opnames and opargs are unchanged and
SEND is untouched, so this is only a stack-effect change, like the one GET_ITER got in gh-132554.
Has this already been discussed elsewhere?
No response given
Links to previous discussion of this feature:
- Use tagged ints for faster iteration #132554, Merge the
GET_ITERandGET_YIELD_FROM_ITERinstructions #145667
Has this already been discussed elsewhere?
No response given
Links to previous discussion of this feature:
No response
Activity
asvetlov commentedon Nov 12, 2026
Both changes are performance neutral. The boost is positive but very small; it probably doesn't affect any real program.
The main reason (along with unification with
GET_ITERetc.) is preparation for https://discuss.python.org/t/speed-up-async-functions-execution-by-40-by-postponing-a-coroutine-object-creation/109808Even if we don't decide to apply the postponed coroutine creation approach, the change still makes sense on its own.