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bpo-41323: Perform 'peephole' optimizations directly on the CFG. #21517

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Merged
markshannon merged 8 commits into from
Jul 30, 2020
Merged

bpo-41323: Perform 'peephole' optimizations directly on the CFG. #21517

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d5b4bda
Move 'peephole' optimizations into compile.c and perform them directl…
markshannon Jul 17, 2020
c480401
Regenerate frozen importlib.
markshannon Jul 17, 2020
6b7019a
Remove commented out code.
markshannon Jul 17, 2020
a2915d5
Two minor code tidy ups.
markshannon Jul 20, 2020
7bc2522
Remove peephole.c
markshannon Jul 20, 2020
fda0bed
Fix leak in mark_reachable.
markshannon Jul 20, 2020
17541b6
Treat jumps to empty blocks as jumps to the following block.
markshannon Jul 21, 2020
1b57a42
Regenerate importlib
markshannon Jul 21, 2020
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4 changes: 0 additions & 4 deletions Lib/test/test_dis.py
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Original file line number Diff line number Diff line change
Expand Up @@ -360,8 +360,6 @@ def _tryfinallyconst(b):
16 CALL_FUNCTION 0
18 POP_TOP
20 RERAISE
22 LOAD_CONST 0 (None)
24 RETURN_VALUE
""" % (_tryfinally.__code__.co_firstlineno + 1,
_tryfinally.__code__.co_firstlineno + 2,
_tryfinally.__code__.co_firstlineno + 4,
Expand All @@ -385,8 +383,6 @@ def _tryfinallyconst(b):
16 CALL_FUNCTION 0
18 POP_TOP
20 RERAISE
22 LOAD_CONST 0 (None)
24 RETURN_VALUE
""" % (_tryfinallyconst.__code__.co_firstlineno + 1,
_tryfinallyconst.__code__.co_firstlineno + 2,
_tryfinallyconst.__code__.co_firstlineno + 4,
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6 changes: 3 additions & 3 deletions Lib/test/test_peepholer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -416,9 +416,9 @@ def f(cond1, cond2):
if cond1: return 4
self.assertNotInBytecode(f, 'JUMP_FORWARD')
# There should be one jump for the while loop.
returns = [instr for instr in dis.get_instructions(f)
if instr.opname == 'JUMP_ABSOLUTE']
self.assertEqual(len(returns), 1)
jumps = [instr for instr in dis.get_instructions(f)
if 'JUMP' in instr.opname]
self.assertEqual(len(jumps), 1)
returns = [instr for instr in dis.get_instructions(f)
if instr.opname == 'RETURN_VALUE']
self.assertLessEqual(len(returns), 2)
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4 changes: 2 additions & 2 deletions Lib/test/test_sys_settrace.py
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Original file line number Diff line number Diff line change
Expand Up @@ -948,7 +948,7 @@ def test_jump_in_nested_finally_3(output):
output.append(11)
output.append(12)

@jump_test(5, 11, [2, 4], (ValueError, 'unreachable'))
@jump_test(5, 11, [2, 4], (ValueError, 'after'))
def test_no_jump_over_return_try_finally_in_finally_block(output):
try:
output.append(2)
Expand Down Expand Up @@ -1457,7 +1457,7 @@ async def test_jump_between_async_with_blocks(output):
async with asynctracecontext(output, 4):
output.append(5)

@jump_test(5, 7, [2, 4], (ValueError, "unreachable"))
@jump_test(5, 7, [2, 4], (ValueError, "after"))
def test_no_jump_over_return_out_of_finally_block(output):
try:
output.append(2)
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2020-07-17-11-31-54.bpo-41323.ChbZHh.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Bytecode optimizations are performed directly on the control flow graph.
This will result in slightly more compact code objects in some
circumstances.
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