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Draft: Intersect optimization for large unions#1471

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ondrejmirtes merged 3 commits intophpstan:1.7.xfrom
neclimdul:type-specification-optimization
Jun 24, 2022
Merged

Draft: Intersect optimization for large unions#1471
ondrejmirtes merged 3 commits intophpstan:1.7.xfrom
neclimdul:type-specification-optimization

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@neclimdul
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Hi,

Just out of curiosity, why creating intermediary variables here?

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otherweise these arrays get sliced within the loop over and over again

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Oh you're right, for some reason I haven't seen the foreach loop ! Well done.

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@neclimdul I feel this array_slice change is a no-brainer and should be submitted as a seperate PR.
the other change breaks the tests atm, so needs further inspection

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I agree, please send a microoptimization PR, then we'll discuss the rest.

neclimdul and others added 3 commits June 24, 2022 13:25
Array slice spends a good bit of time allocating memory for new arrays
even for small arrays. For larger computed unions this can be a
non-trivial amount of time. We can minimize the cost by not repeating
the slice for ever iteration of the inner loop since it doesn't depend
on the loop.
Don't know if this will have side effects so testing needed but if it
works... oh lord.

Fixes #7421 Slow processing of Class::* type hints
@ondrejmirtes ondrejmirtes force-pushed the type-specification-optimization branch from eca9bf2 to 9abc52c Compare June 24, 2022 11:25
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Ah whatever, I really like the optimization, the result can be slightly worse in this case :)

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I pushed test adjustments, will merge it if it comes back green.

@ondrejmirtes ondrejmirtes merged commit f26cff0 into phpstan:1.7.x Jun 24, 2022
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Thank you!

new Variable('bar'),
),
['$foo' => 'Bar', '$bar' => 'Bar'],
['$foo' => 'Bar', '$bar' => 'mixed'], // could be '$bar' => 'Bar'
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This is really annoying to not have anymore :/

I might spend some time on this in the future to bring back.

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I'm sorry, it looked pretty esoteric to me as a way to narrow down types :)

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Maybe we can still do it only for objects, or something like that...

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If it annoys me enough I will find a way to bring it back without a huge performance loss :)

@herndlm
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herndlm commented Jun 24, 2022

I'm kind of travelling right now and could not check - do we know if this improves other big union operations too? E.g. some constant array perf problems also lead to many unions. Or is this a too different case?

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@herndlm likely very specific.

@mvorisek
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@neclimdul this PR has introduced phpstan/phpstan#7550 issue, will you fix it?

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7 participants