[issue11244] Negative tuple elements produce inefficient code.
Antoine Pitrou
report at bugs.python.org
Sat Feb 19 00:09:25 CET 2011
Antoine Pitrou <pitrou at free.fr> added the comment:
Here is a patch that enables advanced (recursive) constant folding.
Example:
python -c "import dis; f=lambda x: x in {(3*-5)+(-1-6),(1,-2,3)*2,None};dis.dis(f)"
With 3.1:
1 0 LOAD_FAST 0 (x)
3 LOAD_CONST 7 (-15)
6 LOAD_CONST 8 (-7)
9 BINARY_ADD
10 LOAD_CONST 10 ((1, -2, 3, 1, -2, 3))
13 LOAD_CONST 11 (None)
16 BUILD_SET 3
19 COMPARE_OP 6 (in)
22 RETURN_VALUE
With 3.2+patch:
1 0 LOAD_FAST 0 (x)
3 LOAD_CONST 14 (frozenset({None, -22, (1, -2, 3, 1, -2, 3)}))
6 COMPARE_OP 6 (in)
9 RETURN_VALUE
----------
Added file: http://bugs.python.org/file20790/constfold.patch
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