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gh-93223: More aggressive Jump-To-Jump elimination (GH-93229)

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Dennis Sweeney 2022-05-27 06:17:59 -04:00 • committed by GitHub
parent 5e34b494a0
commit ddc4a782d3
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GPG key ID: 4AEE18F83AFDEB23
4 changed files with 105 additions and 98 deletions
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17
Lib/test/test_peepholer.py
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@ -43,11 +43,11 @@ class TestTranforms(BytecodeTestCase):
continue
tgt = targets[instr.argval]
# jump to unconditional jump
if tgt.opname in ('JUMP_ABSOLUTE', 'JUMP_FORWARD'):
if tgt.opname in ('JUMP_BACKWARD', 'JUMP_FORWARD'):
self.fail(f'{instr.opname} at {instr.offset} '
f'jumps to {tgt.opname} at {tgt.offset}')
# unconditional jump to RETURN_VALUE
if (instr.opname in ('JUMP_ABSOLUTE', 'JUMP_FORWARD') and
if (instr.opname in ('JUMP_BACKWARD', 'JUMP_FORWARD') and
tgt.opname == 'RETURN_VALUE'):
self.fail(f'{instr.opname} at {instr.offset} '
f'jumps to {tgt.opname} at {tgt.offset}')
@ -352,7 +352,7 @@ class TestTranforms(BytecodeTestCase):
else false_value)
self.check_jump_targets(f)
self.assertNotInBytecode(f, 'JUMP_FORWARD')
self.assertNotInBytecode(f, 'JUMP_ABSOLUTE')
self.assertNotInBytecode(f, 'JUMP_BACKWARD')
returns = [instr for instr in dis.get_instructions(f)
if instr.opname == 'RETURN_VALUE']
self.assertEqual(len(returns), 2)
@ -372,7 +372,7 @@ class TestTranforms(BytecodeTestCase):
self.check_lnotab(f)
def test_elim_jump_to_uncond_jump2(self):
# POP_JUMP_IF_FALSE to JUMP_ABSOLUTE --> POP_JUMP_IF_FALSE to non-jump
# POP_JUMP_IF_FALSE to JUMP_BACKWARD --> POP_JUMP_IF_FALSE to non-jump
def f():
while a:
# Intentionally use two-line expression to test issue37213.
@ -417,6 +417,13 @@ class TestTranforms(BytecodeTestCase):
self.assertInBytecode(f, 'JUMP_IF_FALSE_OR_POP')
self.assertInBytecode(f, 'POP_JUMP_FORWARD_IF_TRUE')
def test_elim_jump_to_uncond_jump4(self):
def f():
for i in range(5):
if i > 3:
print(i)
self.check_jump_targets(f)
def test_elim_jump_after_return1(self):
# Eliminate dead code: jumps immediately after returns can't be reached
def f(cond1, cond2):
@ -429,7 +436,7 @@ class TestTranforms(BytecodeTestCase):
return 5
return 6
self.assertNotInBytecode(f, 'JUMP_FORWARD')
self.assertNotInBytecode(f, 'JUMP_ABSOLUTE')
self.assertNotInBytecode(f, 'JUMP_BACKWARD')
returns = [instr for instr in dis.get_instructions(f)
if instr.opname == 'RETURN_VALUE']
self.assertLessEqual(len(returns), 6)