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Teach the peephole optimizer to fold simple constant expressions.

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Raymond Hettinger 2005-01-02 06:17:33 +00:00
parent 64585988af
commit c34f8673a1
3 changed files with 149 additions and 1 deletions
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28
Lib/test/test_peepholer.py
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@ -102,6 +102,34 @@ class TestTranforms(unittest.TestCase):
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
],)
def test_folding_of_binops_on_constants(self):
for line, elem in (
('a = 2+3+4', '(9)'), # chained fold
('"@"*4', "('@@@@')"), # check string ops
('a="abc" + "def"', "('abcdef')"), # check string ops
('a = 3**4', '(81)'), # binary power
('a = 3*4', '(12)'), # binary multiply
('a = 13/4.0', '(3.25)'), # binary divide
('a = 13//4', '(3)'), # binary floor divide
('a = 14%4', '(2)'), # binary modulo
('a = 2+3', '(5)'), # binary add
('a = 13-4', '(9)'), # binary subtract
('a = (12,13)[1]', '(13)'), # binary subscr
('a = 13 << 2', '(52)'), # binary lshift
('a = 13 >> 2', '(3)'), # binary rshift
('a = 13 & 7', '(5)'), # binary and
('a = 13 ^ 7', '(10)'), # binary xor
('a = 13 | 7', '(15)'), # binary or
):
asm = dis_single(line)
self.assert_(elem in asm, asm)
self.assert_('BINARY_' not in asm)
# Verify that unfoldables are skipped
asm = dis_single('a=2+"b"')
self.assert_('(2)' in asm)
self.assert_("('b')" in asm)
def test_elim_extra_return(self):
# RETURN LOAD_CONST None RETURN --> RETURN
def f(x):