gh-143732: allow dict subclasses to be specialized by kumaraditya303 · Pull Request #148128 · python/cpython · GitHub

Issue: Broader specialization in the Specializing Adaptive Interpreter for better JIT performance #143732

This is revival of #132383 which allowed specialization for dict subclasses which do not override __getitem__. This PR also allows specialization for dict subclasses which do not override __setitem__.

This is primarily targeted for defaultdict which is the most performance critical subclass of dict.

…t-opt

into jit-dict-opt

@markshannon Can you take a look at this? I'd like get this in time for the beta release.

Looks good overall.
The old uops need to be removed and some assertions may no longer be valid.

Also, take care with recorded types. Only strengthen type information on proven or guards, not recorded information.

GitHub doen't put comments in order, it seems. The "above" in the comments refers to earlier lines, not earlier comments.

…t-opt

I still think the assert(PyDict_Check(dict)); asserts should be removed.

I removed the assertions now and added watchers for all cases.

I have made the requested changes; please review again

Thanks for making the requested changes!

@markshannon: please review the changes made to this pull request.

Documentation build overview

📚 cpython-previews | 🛠️ Build #32488413 | 📁 Comparing b40e922 against main (b413bc7)

🔍 Preview build

12 files changed · ± 12 modified

± Modified

I still think we need more watchers. Sorry, I should have spotted that in the last review.

When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.

And if you don't make the requested changes, you will be poked with soft cushions!

…t-opt

Looks like the CI is affected by the Ubuntu outage today.

…t-opt

into jit-dict-opt

I have made the requested changes; please review again

Thanks for making the requested changes!

@markshannon: please review the changes made to this pull request.

This looks good now. Thanks.

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Debian root 3.x (tier-1) has failed when building commit 5847931.

What do you need to do:

Don't panic.
Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/345/builds/14120) and take a look at the build logs.
Check if the failure is related to this commit (5847931) or if it is a false positive.
If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/345/builds/14120

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/support/__init__.py", line 948, in gc_collect
    gc.collect()
    ~~~~~~~~~~^^
ResourceWarning: unclosed file <_io.FileIO name=11 mode='wb' closefd=True>

kumaraditya303 added 2 commits April 5, 2026 21:28

wip

78be7d2

Merge branch 'main' of https://github.com/python/cpython into jit-dic…

86aac31

…t-opt

bedevere-app Bot mentioned this pull request Apr 5, 2026

Broader specialization in the Specializing Adaptive Interpreter for better JIT performance #143732

Open

fix tests

2fdf76f

kumaraditya303 added the skip news label Apr 5, 2026

kumaraditya303 added 2 commits April 5, 2026 21:47

improve tests

0dad4a0

fix test

c953a69

kumaraditya303 marked this pull request as ready for review April 5, 2026 18:39

kumaraditya303 requested review from Fidget-Spinner, markshannon, methane, savannahostrowski and tomasr8 as code owners April 5, 2026 18:39

bedevere-app Bot added the awaiting core review label Apr 5, 2026

kumaraditya303 added the performance Performance or resource usage label Apr 5, 2026

kumaraditya303 added 5 commits April 7, 2026 18:39

Merge branch 'main' into jit-dict-opt

959bdfa

fix _BINARY_OP_SUBSCR_DICT_KNOWN_HASH

38cd1d3

add more tests

e38a5d3

Merge branch 'jit-dict-opt' of https://github.com/kumaraditya303/cpython

1c6b354

into jit-dict-opt

add type assertions

6feb117

markshannon reviewed Apr 30, 2026

View reviewed changes

kumaraditya303 added 6 commits April 30, 2026 17:58

address review

3e88c41

Merge branch 'main' of https://github.com/python/cpython into jit-dic…

af3dbab

…t-opt

fix conflict

61bb5ba

reduce diff

f7e97bd

fix test

f2dc858

fix formatting

17fb6b8

kumaraditya303 requested a review from markshannon April 30, 2026 13:13

bedevere-app Bot added awaiting change review and removed awaiting changes labels Apr 30, 2026

bedevere-app Bot requested a review from markshannon April 30, 2026 17:44

remove more leftover assertions

b40e922

markshannon requested changes May 1, 2026

View reviewed changes

Comment thread Python/optimizer_bytecodes.c

bedevere-app Bot added awaiting changes and removed awaiting change review labels May 1, 2026

kumaraditya303 added 2 commits May 1, 2026 17:10

add watchers in all cases

3387bff

Merge branch 'main' of https://github.com/python/cpython into jit-dic…

94a7cbb

…t-opt

kumaraditya303 requested a review from markshannon May 1, 2026 11:42

kumaraditya303 added 3 commits May 1, 2026 21:22

Merge branch 'main' into jit-dict-opt

f116f96

Merge branch 'main' of https://github.com/python/cpython into jit-dic…

d6b9e26

…t-opt

Merge branch 'jit-dict-opt' of https://github.com/kumaraditya303/cpython

686d630

into jit-dict-opt

bedevere-app Bot added awaiting change review and removed awaiting changes labels May 3, 2026

markshannon approved these changes May 4, 2026

View reviewed changes

bedevere-app Bot added awaiting merge and removed awaiting change review labels May 4, 2026

markshannon merged commit 5847931 into python:main May 4, 2026
79 of 82 checks passed

bedevere-app Bot removed the awaiting merge label May 4, 2026

kumaraditya303 deleted the jit-dict-opt branch May 4, 2026 09:08

kumaraditya303 mentioned this pull request May 29, 2026

gh-100239: specialize dict subclasses with no getitem override #132383

Closed

gh-143732: allow dict subclasses to be specialized by kumaraditya303 · Pull Request #148128 · python/cpython · GitHub

Uh oh!

Uh oh!

gh-143732: allow dict subclasses to be specialized - #148128

gh-143732: allow dict subclasses to be specialized #148128markshannon merged 23 commits intopython:mainpython/cpython:mainfrom kumaraditya303:jit-dict-optkumaraditya303/cpython:jit-dict-optCopy head branch name to clipboard

Conversation

kumaraditya303 commented Apr 5, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

kumaraditya303 commented Apr 29, 2026

Uh oh!

markshannon left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

markshannon commented Apr 30, 2026

Uh oh!

kumaraditya303 commented Apr 30, 2026

Uh oh!

bedevere-app Bot commented Apr 30, 2026

Uh oh!

read-the-docs-community Bot commented Apr 30, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Documentation build overview

Uh oh!

markshannon left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

bedevere-app Bot commented May 1, 2026

Uh oh!

kumaraditya303 commented May 1, 2026

Uh oh!

kumaraditya303 commented May 3, 2026

Uh oh!

bedevere-app Bot commented May 3, 2026

Uh oh!

markshannon left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

bedevere-bot commented May 4, 2026

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

gh-143732: allow dict subclasses to be specialized #148128
markshannon merged 23 commits into
python:mainfrom
kumaraditya303:jit-dict-opt

kumaraditya303 commented Apr 5, 2026 •
edited
Loading

read-the-docs-community Bot commented Apr 30, 2026 •
edited
Loading