Well, it was just a remark. 2016-01-12 0:35 GMT+01:00 Andrew Barnert <abarn...@yahoo.com>: > Are you saying that d[key] = d[key] may or may not increment the version, so > any optimizer can't rely on the fact that it doesn't?
Optimizers don't have to rely on this exactly behaviour. Not incrementing the version on such case avoids dictionary lookups in the guard. My current patch does not increment if the value is the same, and I'm unable to see any performance regression on *micro* benchmarks: https://bugs.python.org/issue26058 So I'm in favor of making guards as efficient as possible and not increment the version in dict ;-) Victor _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
