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gh-126835: make CFG optimizer skip over NOP's when looking for const sequence construction#129703

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Merged
Eclips4 merged 12 commits into from
Feb 9, 2025
Merged

gh-126835: make CFG optimizer skip over NOP's when looking for const sequence construction #129703

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20e61ee
Make `is_constant_sequence` NOP aware
WolframAlph Feb 5, 2025
8b6d294
implement `get_constant_sequence`
WolframAlph Feb 6, 2025
0845cd7
disable debugging code
WolframAlph Feb 6, 2025
d3768ac
address review
WolframAlph Feb 6, 2025
96ff172
address review
WolframAlph Feb 8, 2025
ed7431d
add tests
WolframAlph Feb 8, 2025
f539224
disable debug code
WolframAlph Feb 8, 2025
5866faa
update tests
WolframAlph Feb 8, 2025
578d66b
update tests
WolframAlph Feb 8, 2025
cd92614
update tests
WolframAlph Feb 9, 2025
1574122
Update Lib/test/test_peepholer.py
iritkatriel Feb 9, 2025
16c66f9
Update Lib/test/test_peepholer.py
WolframAlph Feb 9, 2025
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204 changes: 202 additions & 2 deletions Lib/test/test_peepholer.py
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Original file line numberDiff line numberDiff line change
Expand Up@@ -36,6 +36,13 @@ def count_instr_recursively(f, opname):
return count


def get_binop_argval(arg):
for i, nb_op in enumerate(opcode._nb_ops):
if arg == nb_op[0]:
return i
assert False, f"{arg} is not a valid BINARY_OP argument."


class TestTranforms(BytecodeTestCase):

def check_jump_targets(self, code):
Expand DownExpand Up@@ -518,8 +525,7 @@ def test_folding_subscript(self):
('("a" * 10)[10]', True),
('(1, (1, 2))[2:6][0][2-1]', True),
]
subscr_argval = 26
assert opcode._nb_ops[subscr_argval][0] == 'NB_SUBSCR'
subscr_argval = get_binop_argval('NB_SUBSCR')
for expr, has_error in tests:
with self.subTest(expr=expr, has_error=has_error):
code = compile(expr, '', 'single')
Expand DownExpand Up@@ -1062,6 +1068,200 @@ def test_conditional_jump_forward_non_const_condition(self):
consts=[0, 1, 2, 3, 4],
expected_consts=[0, 2, 3])

def test_list_exceeding_stack_use_guideline(self):
def f():
return [
0, 1, 2, 3, 4,
5, 6, 7, 8, 9,
10, 11, 12, 13, 14,
15, 16, 17, 18, 19,
20, 21, 22, 23, 24,
25, 26, 27, 28, 29,
30, 31, 32, 33, 34,
35, 36, 37, 38, 39
]
self.assertEqual(f(), list(range(40)))

def test_set_exceeding_stack_use_guideline(self):
def f():
return {
0, 1, 2, 3, 4,
5, 6, 7, 8, 9,
10, 11, 12, 13, 14,
15, 16, 17, 18, 19,
20, 21, 22, 23, 24,
25, 26, 27, 28, 29,
30, 31, 32, 33, 34,
35, 36, 37, 38, 39
}
self.assertEqual(f(), frozenset(range(40)))

def test_multiple_foldings(self):
before = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_SMALL_INT', 2, 0),
('BUILD_TUPLE', 1, 0),
('LOAD_SMALL_INT', 0, 0),
('BINARY_OP', get_binop_argval('NB_SUBSCR'), 0),
('BUILD_TUPLE', 2, 0),
('RETURN_VALUE', None, 0)
]
after = [
('LOAD_CONST', 1, 0),
('RETURN_VALUE', None, 0)
]
self.cfg_optimization_test(before, after, consts=[], expected_consts=[(2,), (1, 2)])

def test_build_empty_tuple(self):
before = [
('BUILD_TUPLE', 0, 0),
('RETURN_VALUE', None, 0),
]
after = [
('LOAD_CONST', 0, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(before, after, consts=[], expected_consts=[()])

def test_fold_tuple_of_constants(self):
before = [
('NOP', None, 0),
('LOAD_SMALL_INT', 1, 0),
('NOP', None, 0),
('LOAD_SMALL_INT', 2, 0),
('NOP', None, 0),
('NOP', None, 0),
('LOAD_SMALL_INT', 3, 0),
('NOP', None, 0),
('BUILD_TUPLE', 3, 0),
('RETURN_VALUE', None, 0),
]
after = [
('LOAD_CONST', 0, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(before, after, consts=[], expected_consts=[(1, 2, 3)])

Comment thread
WolframAlph marked this conversation as resolved.
# not enough consts
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_SMALL_INT', 2, 0),
('BUILD_TUPLE', 3, 0),
('RETURN_VALUE', None, 0)
]
self.cfg_optimization_test(same, same, consts=[])

# not all consts
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_NAME', 0, 0),
('LOAD_SMALL_INT', 2, 0),
('BUILD_TUPLE', 3, 0),
('RETURN_VALUE', None, 0)
]
self.cfg_optimization_test(same, same, consts=[])

def test_optimize_if_const_list(self):
before = [
('NOP', None, 0),
('LOAD_SMALL_INT', 1, 0),
('NOP', None, 0),
('LOAD_SMALL_INT', 2, 0),
('NOP', None, 0),
('NOP', None, 0),
('LOAD_SMALL_INT', 3, 0),
('NOP', None, 0),
('BUILD_LIST', 3, 0),
('RETURN_VALUE', None, 0),
]
after = [
('BUILD_LIST', 0, 0),
('LOAD_CONST', 0, 0),
('LIST_EXTEND', 1, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(before, after, consts=[], expected_consts=[(1, 2, 3)])

# need minimum 3 consts to optimize
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_SMALL_INT', 2, 0),
('BUILD_LIST', 2, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(same, same, consts=[])

# not enough consts
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_SMALL_INT', 2, 0),
('LOAD_SMALL_INT', 3, 0),
('BUILD_LIST', 4, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(same, same, consts=[])

# not all consts
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_NAME', 0, 0),
('LOAD_SMALL_INT', 3, 0),
('BUILD_LIST', 3, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(same, same, consts=[])

def test_optimize_if_const_set(self):
before = [
('NOP', None, 0),
('LOAD_SMALL_INT', 1, 0),
('NOP', None, 0),
('LOAD_SMALL_INT', 2, 0),
('NOP', None, 0),
('NOP', None, 0),
('LOAD_SMALL_INT', 3, 0),
('NOP', None, 0),
('BUILD_SET', 3, 0),
('RETURN_VALUE', None, 0),
]
after = [
('BUILD_SET', 0, 0),
('LOAD_CONST', 0, 0),
('SET_UPDATE', 1, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(before, after, consts=[], expected_consts=[frozenset({1, 2, 3})])

# need minimum 3 consts to optimize
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_SMALL_INT', 2, 0),
('BUILD_SET', 2, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(same, same, consts=[])

# not enough consts
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_SMALL_INT', 2, 0),
('LOAD_SMALL_INT', 3, 0),
('BUILD_SET', 4, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(same, same, consts=[])

# not all consts
same = [
('LOAD_SMALL_INT', 1, 0),
('LOAD_NAME', 0, 0),
('LOAD_SMALL_INT', 3, 0),
('BUILD_SET', 3, 0),
('RETURN_VALUE', None, 0),
]
self.cfg_optimization_test(same, same, consts=[])


def test_conditional_jump_forward_const_condition(self):
# The unreachable branch of the jump is removed, the jump
# becomes redundant and is replaced by a NOP (for the lineno)
Expand Down
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