bpo-32925: Optimized iterating and containing test for literal lists (GH-5842)

consisting of non-constants: `x in [a, b]` and `for x in [a, b]`.
The case of all constant elements already was optimized.
This commit is contained in:
Serhiy Storchaka 2018-03-11 10:54:47 +02:00 committed by GitHub
parent 4e2442505c
commit 3f7e9aa2ef
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3 changed files with 44 additions and 2 deletions

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@ -3,6 +3,19 @@ import unittest
from test.bytecode_helper import BytecodeTestCase
def count_instr_recursively(f, opname):
count = 0
for instr in dis.get_instructions(f):
if instr.opname == opname:
count += 1
if hasattr(f, '__code__'):
f = f.__code__
for c in f.co_consts:
if hasattr(c, 'co_code'):
count += count_instr_recursively(c, opname)
return count
class TestTranforms(BytecodeTestCase):
def test_unot(self):
@ -311,6 +324,17 @@ class TestTranforms(BytecodeTestCase):
self.assertFalse(instr.opname.startswith('BINARY_'))
self.assertFalse(instr.opname.startswith('BUILD_'))
def test_in_literal_list(self):
def containtest():
return x in [a, b]
self.assertEqual(count_instr_recursively(containtest, 'BUILD_LIST'), 0)
def test_iterate_literal_list(self):
def forloop():
for x in [a, b]:
pass
self.assertEqual(count_instr_recursively(forloop, 'BUILD_LIST'), 0)
class TestBuglets(unittest.TestCase):

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@ -0,0 +1,3 @@
Optimized iterating and containing test for literal lists consisting of
non-constants: ``x in [a, b]`` and ``for x in [a, b]``. The case of all
constant elements already was optimized.

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@ -369,7 +369,8 @@ fold_subscr(expr_ty node, PyArena *arena, int optimize)
}
/* Change literal list or set of constants into constant
tuple or frozenset respectively.
tuple or frozenset respectively. Change literal list of
non-constants into tuple.
Used for right operand of "in" and "not in" tests and for iterable
in "for" loop and comprehensions.
*/
@ -378,7 +379,21 @@ fold_iter(expr_ty arg, PyArena *arena, int optimize)
{
PyObject *newval;
if (arg->kind == List_kind) {
newval = make_const_tuple(arg->v.List.elts);
/* First change a list into tuple. */
asdl_seq *elts = arg->v.List.elts;
Py_ssize_t n = asdl_seq_LEN(elts);
for (Py_ssize_t i = 0; i < n; i++) {
expr_ty e = (expr_ty)asdl_seq_GET(elts, i);
if (e->kind == Starred_kind) {
return 1;
}
}
expr_context_ty ctx = arg->v.List.ctx;
arg->kind = Tuple_kind;
arg->v.Tuple.elts = elts;
arg->v.Tuple.ctx = ctx;
/* Try to create a constant tuple. */
newval = make_const_tuple(elts);
}
else if (arg->kind == Set_kind) {
newval = make_const_tuple(arg->v.Set.elts);