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GeezerVison is showing github.com — gh-143732: Add specialization for TO_BOOL by eendebakpt · Pull Request #148113 · python/cpython

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@eendebakpt

@eendebakpt eendebakpt commented Apr 4, 2026 •
edited by bedevere-app Bot
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We add TO_BOOL_GENERIC as suggested in #143732 (comment). This adds type information for several builtin classes. We also add _TO_BOOL_DICT (tier 2). In the jit conversion of a dict to bool is about 30% faster.

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

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eendebakpt and others added 5 commits March 25, 2026 22:53
@eendebakpt @claude
Add TO_BOOL_GENERIC specialization and _TO_BOOL_DICT JIT optimization
395bdfc 
- Add TO_BOOL_GENERIC: a catch-all specialization for types not covered
  by existing TO_BOOL variants (dict, tuple, float, set, bytes, frozenset,
  etc. and heap types with __bool__/__len__). Records type info for the JIT.

- Add _TO_BOOL_DICT: a tier2-only uop that checks dict.ma_used directly
  instead of calling PyObject_IsTrue(). The JIT optimizer replaces _TO_BOOL
  with _TO_BOOL_DICT when the type is known to be dict or frozendict.

- Fix _GUARD_TYPE_VERSION optimizer handler to resolve types from recorded
  type info even when the type version cache has a collision. This enables
  the optimizer to eliminate redundant type guards (e.g. _GUARD_NOS_LIST)
  in more cases.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
@eendebakpt
Merge branch 'main' into to_bool_generic
8e62e9f
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refactor
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refactor
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refactor
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eendebakpt requested review from Fidget-Spinner, markshannon, savannahostrowski and tomasr8 as code owners April 4, 2026 21:51
@bedevere-app bedevere-app Bot added the awaiting review label Apr 4, 2026
@bedevere-app bedevere-app Bot mentioned this pull request Apr 4, 2026
Broader specialization in the Specializing Adaptive Interpreter for better JIT performance #143732
Open
eendebakpt
eendebakpt commented Apr 5, 2026
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Comment thread Lib/test/test_opcache.py
self.assert_specialized(to_bool_str, "TO_BOOL_STR")
self.assert_no_opcode(to_bool_str, "TO_BOOL")

def to_bool_generic_dict():

@eendebakpt eendebakpt Apr 5, 2026

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There is quite some redundancy in the added tests (and also the existing tests). We could refactor this, but it is a bit tricky as re-using the same method (with different arguments) makes it more difficult to reason about the specialization that takes place.

If we want this, I suggest we open a separate PR.

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eendebakpt
eendebakpt commented Apr 5, 2026
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Comment thread Python/optimizer_bytecodes.c
// already added one earlier.
if (sym_set_type_version(owner, type_version)) {
// sym_set_type_version can resolve the type from recorded type info
// even when the version cache has a collision

@eendebakpt eendebakpt Apr 5, 2026

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This change has as side effect the list.append needs less checks.

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@eendebakpt eendebakpt changed the title Draft: gh-143732: Add specialization for TO_BOOL gh-143732: Add specialization for TO_BOOL Apr 5, 2026
eendebakpt and others added 4 commits April 5, 2026 21:20
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Merge branch 'main' into to_bool_generic
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📜🤖 Added by blurb_it.
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Merge branch 'main' into to_bool_generic
39f9e66
@markshannon

markshannon commented Apr 7, 2026

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I don't think we want TO_BOOL_GENERIC as it is basically duplicating TO_BOOL. The "generic" form is only useful if we also add a _PY form that inlines calls to __bool__() for classes where __bool__() is implemented in Python.
In that case we need the "generic" form to guard against __bool__() being implemented in Python, so we always inline the call.
I'm not sure if this is worth it for __bool__ as much as for other __dunder__ functions.

What you can do is add the _RECORD_TOS_TYPE uop to TO_BOOL and use that to implement the _TO_BOOL_DICT optimization.

You might also want to add _TO_BOOL_SIZED and apply it to any class where __bool__() is equivalent to Py_SIZE(obj) != 0. We could then specialize TO_BOOL for tuples, bytes, bytearrays and others, in the JIT.
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@eendebakpt eendebakpt mentioned this pull request Apr 8, 2026
gh-143732: Add tier2 specialization for TO_BOOL #148271
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@eendebakpt

eendebakpt commented Apr 8, 2026

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@markshannon It seems I misinterpreted the comments at the issue. I though the TO_BOOL_GENERIC/TO_BOOL_PY pair would cover most (all types) and allow tier2 specialization.

I am having some trouble adding the _RECORD_TOS_TYPE to TO_BOOL as that has _SPECIALIZE_TO_BOOL and I cannot combine the two. I created a separate PR with just the tier2 opcodes. (they work in the jit, but could benefit from more type information from either a _RECORD_TOS_TYPE or tier1 opcodes).
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@markshannon

markshannon commented Apr 9, 2026

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#148285
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@markshannon

markshannon commented Apr 30, 2026

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The issue with _SPECIALIZE_TO_BOOL preventing recording has been fixed, if you want to pick this up again
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@eendebakpt

eendebakpt commented Apr 30, 2026

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@markshannon I am closing this in favor of #148271. That PR only currently adds the tier2 opcodes (not yet the recording uop). I will add the recording uop on top of the PR or a followup PR depending how hard it is.
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@eendebakpt eendebakpt closed this Apr 30, 2026
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@markshannon markshannon Awaiting requested review from markshannon markshannon is a code owner
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