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gh-148083: Constant-fold _CONTAINS_OP_SET for frozenset#148084

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Merged
corona10 merged 2 commits into from
Apr 4, 2026
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gh-148083: Constant-fold _CONTAINS_OP_SET for frozenset #148084

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gh-148083: Constant-fold _CONTAINS_OP_SET for frozenset
corona10 Apr 4, 2026
98b11c4
nit
corona10 Apr 4, 2026
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20 changes: 19 additions & 1 deletion Lib/test/test_capi/test_opt.py
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Original file line numberDiff line numberDiff line change
Expand Up@@ -23,6 +23,9 @@
# For frozendict JIT tests
FROZEN_DICT_CONST = frozendict(x=1, y=2)

# For frozenset JIT tests
FROZEN_SET_CONST = frozenset({1, 2, 3})

class _GenericKey:
pass

Expand DownExpand Up@@ -2169,7 +2172,8 @@ def f(n):
self.assertIsNotNone(ex)
uops = get_opnames(ex)
self.assertNotIn("_GUARD_TOS_ANY_SET", uops)
self.assertIn("_CONTAINS_OP_SET", uops)
# _CONTAINS_OP_SET is constant-folded away for frozenset literals
self.assertIn("_INSERT_2_LOAD_CONST_INLINE_BORROW", uops)

def test_remove_guard_for_known_type_tuple(self):
def f(n):
Expand DownExpand Up@@ -4399,6 +4403,20 @@ def testfunc(n):
# lookup result is folded to constant 1, so comparison is optimized away
self.assertNotIn("_COMPARE_OP_INT", uops)

def test_contains_op_frozenset_const_fold(self):
def testfunc(n):
x = 0
for _ in range(n):
if 1 in FROZEN_SET_CONST:
x += 1
return x

res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
self.assertEqual(res, TIER2_THRESHOLD)
self.assertIsNotNone(ex)
uops = get_opnames(ex)
self.assertNotIn("_CONTAINS_OP_SET", uops)

def test_binary_subscr_list_slice(self):
def testfunc(n):
x = 0
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2026-04-04-20-59-12.gh-issue-148083.9ZHNBN.rst
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@@ -0,0 +1 @@
Constant-fold ``_CONTAINS_OP_SET`` for :class:`frozenset`. Patch by Donghee Na.
1 change: 1 addition & 0 deletions Python/optimizer_analysis.c
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Expand Up@@ -30,6 +30,7 @@
#include "pycore_unicodeobject.h"
#include "pycore_ceval.h"
#include "pycore_floatobject.h"
#include "pycore_setobject.h"

#include <stdarg.h>
#include <stdbool.h>
Expand Down
3 changes: 3 additions & 0 deletions Python/optimizer_bytecodes.c
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Expand Up@@ -706,6 +706,9 @@ dummy_func(void) {
b = sym_new_type(ctx, &PyBool_Type);
l = left;
r = right;
if (sym_matches_type(right, &PyFrozenSet_Type)) {
REPLACE_OPCODE_IF_EVALUATES_PURE(left, right, b);
}
}

op(_CONTAINS_OP_DICT, (left, right -- b, l, r)) {
Expand Down
44 changes: 44 additions & 0 deletions Python/optimizer_cases.c.h
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3 changes: 2 additions & 1 deletion Python/optimizer_symbols.c
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Expand Up@@ -283,7 +283,8 @@ _Py_uop_sym_is_safe_const(JitOptContext *ctx, JitOptRef sym)
(typ == &PyFloat_Type) ||
(typ == &_PyNone_Type) ||
(typ == &PyBool_Type) ||
(typ == &PyFrozenDict_Type);
(typ == &PyFrozenDict_Type) ||
(typ == &PyFrozenSet_Type);

@Fidget-SpinnerFidget-SpinnerApr 4, 2026

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Ah wait this isnt really safe for the case of frozenset IN frozenset

Basically it's only safe if the LHS is a non-container safe type with pure hash function, and the RHS is frozenset

@Fidget-SpinnerFidget-SpinnerApr 4, 2026

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So you need to add a check that says LHS != Frozenset/FrozenDict type.

@Fidget-SpinnerFidget-SpinnerApr 4, 2026

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Same for frozendict btw.

@corona10corona10Apr 4, 2026

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I will send a new PR for this :)

}

void
Expand Down
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