Avoid unnecessary keyword arguments check in fallback rrule #308
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oxinabox
reviewed
Mar 8, 2021
oxinabox
reviewed
Mar 8, 2021
oxinabox
reviewed
Mar 8, 2021
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The expansion `rrule(::Any, ::Vararg{Any}; kwargs...)` actually
generates two methods. One along the lines of:
```
(::typeof(Core.kwfunc(rrule))(kwargs, ::typeof(rrule), ::Any, ::Vararg{Any}) = nothing
```
and the other that just calls it:
```
rrule(a::Any, b::Vararg{Any}) = Core.kwfunc(rrule)(NamedTuple{}(), a, b...)
```
The compiler handles this fallback well, since it's used all over the place,
but the cost to infer it is non-zero. Of course, in the AD use case, this
fallback method is visited literally on every call, so saving a tiny amount
of inference/compile time actually leads to noticable improvements over
a whole AD problem.
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Contributor
Author
|
@oxinabox should be good to go |
Member
|
Will review and merge tomorrow |
oxinabox
reviewed
Mar 24, 2021
oxinabox
reviewed
Mar 24, 2021
oxinabox
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Mar 24, 2021
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The expansion
rrule(::Any, ::Vararg{Any}; kwargs...)actuallygenerates two methods. One along the lines of:
and the other that just calls it:
The compiler handles this fallback well, since it's used all over the place,
but the cost to infer it is non-zero. Of course, in the AD use case, this
fallback method is visited literally on every call, so saving a tiny amount
of inference/compile time actually leads to noticable improvements over
a whole AD problem.