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gh-148083: Prevent constant folding when lhs is container types #148090

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Merged
corona10 merged 2 commits into from
Apr 4, 2026
Merged

gh-148083: Prevent constant folding when lhs is container types #148090

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1d54f5c
gh-148083: Prevent constant folding when lhs is container types
corona10 Apr 4, 2026
561daaf
Address code review
corona10 Apr 4, 2026
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1 change: 1 addition & 0 deletions Include/internal/pycore_optimizer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -394,6 +394,7 @@ extern JitOptRef _Py_uop_sym_new_type(
extern JitOptRef _Py_uop_sym_new_const(JitOptContext *ctx, PyObject *const_val);
extern JitOptRef _Py_uop_sym_new_const_steal(JitOptContext *ctx, PyObject *const_val);
bool _Py_uop_sym_is_safe_const(JitOptContext *ctx, JitOptRef sym);
bool _Py_uop_sym_is_container(JitOptRef sym);
_PyStackRef _Py_uop_sym_get_const_as_stackref(JitOptContext *ctx, JitOptRef sym);
extern JitOptRef _Py_uop_sym_new_null(JitOptContext *ctx);
extern bool _Py_uop_sym_has_type(JitOptRef sym);
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1 change: 1 addition & 0 deletions Python/optimizer_analysis.c
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Expand Up @@ -252,6 +252,7 @@ add_op(JitOptContext *ctx, _PyUOpInstruction *this_instr,
#define sym_is_not_null _Py_uop_sym_is_not_null
#define sym_is_const _Py_uop_sym_is_const
#define sym_is_safe_const _Py_uop_sym_is_safe_const
#define sym_is_container _Py_uop_sym_is_container
#define sym_get_const _Py_uop_sym_get_const
#define sym_new_const_steal _Py_uop_sym_new_const_steal
#define sym_get_const_as_stackref _Py_uop_sym_get_const_as_stackref
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6 changes: 4 additions & 2 deletions Python/optimizer_bytecodes.c
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Expand Up @@ -515,7 +515,8 @@ dummy_func(void) {
res = sym_new_not_null(ctx);
ds = dict_st;
ss = sub_st;
if (sym_matches_type(dict_st, &PyFrozenDict_Type)) {
if (!sym_is_container(sub_st) &&
sym_matches_type(dict_st, &PyFrozenDict_Type)) {
REPLACE_OPCODE_IF_EVALUATES_PURE(dict_st, sub_st, res);
}
}
Expand Down Expand Up @@ -706,7 +707,8 @@ dummy_func(void) {
b = sym_new_type(ctx, &PyBool_Type);
l = left;
r = right;
if (sym_matches_type(right, &PyFrozenSet_Type)) {
if (!sym_is_container(left) &&
sym_matches_type(right, &PyFrozenSet_Type)) {
REPLACE_OPCODE_IF_EVALUATES_PURE(left, right, b);
}
}
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6 changes: 4 additions & 2 deletions Python/optimizer_cases.c.h
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15 changes: 15 additions & 0 deletions Python/optimizer_symbols.c
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Expand Up @@ -287,6 +287,21 @@ _Py_uop_sym_is_safe_const(JitOptContext *ctx, JitOptRef sym)
(typ == &PyFrozenSet_Type);
}

bool
_Py_uop_sym_is_container(JitOptRef sym)
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@Fidget-Spinner Fidget-Spinner Apr 4, 2026

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It's better to make this an allowlist, so we should say sym_is_not_container and check for the usual int float str etc

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@Fidget-Spinner Fidget-Spinner Apr 4, 2026

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Otherwise custom containers might be let through

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@corona10 corona10 Apr 4, 2026

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Done :)

{
PyTypeObject *typ = _Py_uop_sym_get_type(sym);
if (typ == NULL) {
return false;
}
return (typ == &PyFrozenSet_Type) ||
(typ == &PyFrozenDict_Type) ||
(typ == &PySet_Type) ||
(typ == &PyDict_Type) ||
(typ == &PyList_Type) ||
(typ == &PyTuple_Type);
}

void
_Py_uop_sym_set_type(JitOptContext *ctx, JitOptRef ref, PyTypeObject *typ)
{
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