Chris Angelico, 12.08.2012 01:22: >> Other idea to improve this optimizer: >> - move invariant out of loops. Example: "x=[]; for i in range(10): >> x.append(i)" => "x=[]; x_append=x.append; for i in range(10): >> x_append(i)". Require to infer the type of variables. > > But this is risky. It's theoretically possible for x.append to replace > itself. Sure it may not be a normal or common thing to do, but it's > possible.
Not only that. It changes semantics. If x.append is not defined, the exception would now be raised outside of the loop, and the loop itself may have side-effects already. In fact, the mere lookup of x.append may have side effects as well ... Stefan _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
