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Teach the peepholer to fold unary operations on constants.

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Afterwards, -0.5 loads in a single step and no longer requires a runtime
UNARY_NEGATIVE operation.
This commit is contained in:
Raymond Hettinger 2005-02-20 12:46:54 +00:00
parent 80121491e0
commit afd842f5b2
1 changed files with 19 additions and 0 deletions
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19
Lib/test/test_peepholer.py
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@ -133,6 +133,25 @@ class TestTranforms(unittest.TestCase):
asm = dis_single('a="x"*1000')
self.assert_('(1000)' in asm)
def test_folding_of_unaryops_on_constants(self):
for line, elem in (
('`1`', "('1')"), # unary convert
('-0.5', '(-0.5)'), # unary negative
('~-2', '(1)'), # unary invert
):
asm = dis_single(line)
self.assert_(elem in asm, asm)
self.assert_('UNARY_' not in asm)
# Verify that unfoldables are skipped
for line, elem in (
('-"abc"', "('abc')"), # unary negative
('~"abc"', "('abc')"), # unary invert
):
asm = dis_single(line)
self.assert_(elem in asm, asm)
self.assert_('UNARY_' in asm)
def test_elim_extra_return(self):
# RETURN LOAD_CONST None RETURN --> RETURN
def f(x):