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gh-143414: Implement unique reference tracking for JIT, optimize unpacking of such tuples#144300

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Fidget-Spinner merged 36 commits into
python:mainfrom
reidenong:branch-unique-reference-tracking
Mar 22, 2026
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gh-143414: Implement unique reference tracking for JIT, optimize unpacking of such tuples#144300
Fidget-Spinner merged 36 commits into
python:mainfrom
reidenong:branch-unique-reference-tracking

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@reidenong

@reidenong reidenong commented Jan 28, 2026 •
edited by bedevere-app Bot
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  1. Implements unique reference tracking to references in the JIT Optimizer.
  2. Uses the unique reference tracking to eliminate unnecessary reference counting for uniquely referenced tuples. ex:
x, y, z = f()

Some notes:

  • Only implements the unique reference tracking (and relevant optimization) for tuples in _BUILD_TUPLE, to be extended to other objects in the future
  • Objects are deemed as not uniquely referenced when they are made aliases or duplicated, in uops of _LOAD_FAST_* and _COPY.

Would appreciate any feedback.
Thanks

@bedevere-app bedevere-app Bot mentioned this pull request Jan 28, 2026
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@reidenong

reidenong commented Jan 28, 2026 •
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Discussed with @Fidget-Spinner, will reopen the PR after implementing PyStackRef_CLOSE_SPECIALIZED for _UNPACK_SEQUENCE_UNIQUE_TUPLE

@reidenong reidenong marked this pull request as draft January 28, 2026 18:38
@reidenong reidenong marked this pull request as ready for review January 29, 2026 11:04
@Fidget-Spinner

Fidget-Spinner commented Jan 29, 2026

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Windows Ci failure looks possibly related, can you please look into it?

@reidenong reidenong marked this pull request as draft January 31, 2026 06:39
@reidenong reidenong marked this pull request as ready for review January 31, 2026 16:36
Fidget-Spinner
Fidget-Spinner reviewed Jan 31, 2026
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This is excellent. Just 2 comments, then I think it's safe to merge.

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@reidenong

reidenong commented Feb 21, 2026

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I have made the requested changes; please review again. Thanks!

@bedevere-app

bedevere-app Bot commented Feb 21, 2026

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Thanks for making the requested changes!

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

@bedevere-app bedevere-app Bot requested a review from markshannon February 21, 2026 05:18
@reidenong

reidenong commented Mar 9, 2026

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@markshannon Hi mark, please take a look at this PR when you have the time. Thanks!

@markshannon markshannon mentioned this pull request Mar 13, 2026
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@Fidget-Spinner

Fidget-Spinner commented Mar 22, 2026 •
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@reidenong sorry can you please merge in main to this PR? I'll try to get this in this week.

Fidget-Spinner
Fidget-Spinner approved these changes Mar 22, 2026
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Nice!

@Fidget-Spinner Fidget-Spinner dismissed markshannon’s stale review March 22, 2026 16:56

Mark's review has already been addressed and given 2 weeks for a response.

Hide details View details @Fidget-Spinner Fidget-Spinner merged commit e36f8db into python:main Mar 22, 2026
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@eendebakpt eendebakpt mentioned this pull request Mar 22, 2026
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CuriousLearner added a commit to CuriousLearner/cpython that referenced this pull request Mar 23, 2026
@CuriousLearner
Merge branch 'main' of github.com:python/cpython into fix-pythongh-13… …
3e05fa3 
…8577

* 'main' of github.com:python/cpython:
  pythongh-146197: Run -m test.pythoninfo on the Emscripten CI (python#146332)
  pythongh-146325: Use `test.support.requires_fork` in test_fastpath_cache_cleared_in_forked_child (python#146330)
  pythongh-146197: Add Emscripten to CI (python#146198)
  pythongh-143387: Raise an exception instead of returning None when metadata file is missing. (python#146234)
  pythongh-108907: ctypes: Document _type_ codes (pythonGH-145837)
  pythongh-146175: Soft-deprecate outdated macros; convert internal usage (pythonGH-146178)
  pythongh-146056: Rework ref counting in treebuilder_handle_end() (python#146167)
  Add a warning about untrusted input to `configparser` docs (python#146276)
  pythongh-145264: Do not ignore excess Base64 data after the first padded quad (pythonGH-145267)
  pythongh-146308: Fix error handling issues in _remote_debugging module (python#146309)
  pythongh-146192: Add base32 support to binascii (pythonGH-146193)
  pythongh-135953: Properly obtain main thread identifier in Gecko Collector (python#146045)
  pythongh-143414: Implement unique reference tracking for JIT, optimize unpacking of such tuples (pythonGH-144300)
  pythongh-146261: Fix bug in `_Py_uop_sym_set_func_version` (pythonGH-146291)
  pythongh-145144: Add more tests for UserList, UserDict, etc (pythonGH-145145)
  pythongh-143959: Fix test_datetime if _datetime is unavailable (pythonGH-145248)
  pythongh-146245: Fix reference and buffer leaks via audit hook in socket module (pythonGH-146248)
  pythongh-140049: Colorize exception notes in `traceback.py` (python#140051)
  Update docs for pythongh-146056 (pythonGH-146213)
@eendebakpt

eendebakpt commented Apr 4, 2026

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FYI: Adding unique reference tracking for lists is possible in a similar way as done for tuples in this PR. A prototype is main...eendebakpt:cpython:unique_list. Performance improves, but I am not sure unique list unpacking is as relevant as tuple unpackage @Fidget-Spinner

@pablogsal pablogsal mentioned this pull request Apr 4, 2026
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ljfp pushed a commit to ljfp/cpython that referenced this pull request Apr 25, 2026
@reidenong @Fidget-Spinner @ljfp
pythongh-143414: Implement unique reference tracking for JIT, optimiz… …
8d05049 
…e unpacking of such tuples (pythonGH-144300)

Co-authored-by: Ken Jin <kenjin4096@gmail.com>
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@Fidget-Spinner Fidget-Spinner Fidget-Spinner approved these changes

@tomasr8 tomasr8 Awaiting requested review from tomasr8 tomasr8 is a code owner

@savannahostrowski savannahostrowski savannahostrowski is a code owner

@markshannon markshannon Awaiting requested review from markshannon markshannon is a code owner

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