[New-bugs-announce] [issue6690] BUILD_SET followed by COMPARE_OP (in) can be optimized if all items are consts

[Alex]

New submission from Alex <alex.gaynor at gmail.com>:

Just like we turn BUILD_LIST; COMPARE_OP (in) into a LOAD_CONST if all
the members are consts, we can do the same for BUILD_SET, instead
turning it into a LOAD_CONST of a frozenset.  The following is the
bytecode that is current produced for each datastructure.

>>> dis.dis(lambda o: o in (1,2,3))
  1           0 LOAD_FAST                0 (o) 
              3 LOAD_CONST               3 ((1, 2, 3)) 
              6 COMPARE_OP               6 (in) 
              9 RETURN_VALUE         
>>> dis.dis(lambda o: o in [1,2,3])
  1           0 LOAD_FAST                0 (o) 
              3 LOAD_CONST               3 ((1, 2, 3)) 
              6 COMPARE_OP               6 (in) 
              9 RETURN_VALUE         
>>> dis.dis(lambda o: o in {1,2,3})
  1           0 LOAD_FAST                0 (o) 
              3 LOAD_CONST               0 (1) 
              6 LOAD_CONST               1 (2) 
              9 LOAD_CONST               2 (3) 
             12 BUILD_SET                3 
             15 COMPARE_OP               6 (in) 
             18 RETURN_VALUE

----------
components: Interpreter Core
messages: 91506
nosy: alex
severity: normal
status: open
title: BUILD_SET followed by COMPARE_OP (in) can be optimized if all items are consts
versions: Python 3.2

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue6690>
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