Message 384127 - Python tracker

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In-reply-to
Author	BTaskaya
Recipients	BTaskaya, Mark.Shannon, christian.heimes, josh.r, mark.dickinson, pablogsal, rhettinger, serhiy.storchaka, terry.reedy
Date	2020年12月31日.18:05:13
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1609437913.63.0.250834614327.issue42454@roundup.psfhosted.org>

Content
I've given this another shot, but even though I was able to create a patch that preserved slices as (type(slice), start, stop, step) tuples in the consts_cache, this final optimization prevented me to finalize it; 😃https://github.com/python/cpython/blob/master/Python/compile.c#L5855-L5858 So, unless anyone else came up with a reasonable idea to do this optimization at the compile-time without actually making them hashable, I am re-proposing the idea of making them hashable. Pro: - Up to %30+ speedup on slicing with constants (extremely common) Cons: - Mappings accepts slices, which would rarely lead some esoteric cases (like the examples given) Comments would be appreciated

Content

I've given this another shot, but even though I was able to create a patch that preserved slices as (type(slice), start, stop, step) tuples in the consts_cache, this final optimization prevented me to finalize it; 😃https://github.com/python/cpython/blob/master/Python/compile.c#L5855-L5858
So, unless anyone else came up with a reasonable idea to do this optimization at the compile-time without actually making them hashable, I am re-proposing the idea of making them hashable.
Pro:
 - Up to %30+ speedup on slicing with constants (extremely common)
Cons:
 - Mappings accepts slices, which would rarely lead some esoteric cases (like the examples given)
Comments would be appreciated

History
Date	User	Action	Args
2020年12月31日 18:05:13	BTaskaya	set	recipients: + BTaskaya, rhettinger, terry.reedy, mark.dickinson, christian.heimes, Mark.Shannon, serhiy.storchaka, josh.r, pablogsal
2020年12月31日 18:05:13	BTaskaya	set	messageid: <1609437913.63.0.250834614327.issue42454@roundup.psfhosted.org>
2020年12月31日 18:05:13	BTaskaya	link	issue42454 messages
2020年12月31日 18:05:13	BTaskaya	create

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