effects: power-up effects analysis for array operations #47154

aviatesk · 2022-10-13T12:31:38Z

Mostly by making use of newly added :inaccessiblememonly effect property.
Now we can fold simple vector operations like:

julia> function simple_vec_ops(T, op!, op, xs...)
           a = T[]
           op!(a, xs...)
           return op(a)
       end;
simple_vec_ops (generic function with 1 method)

julia> for T = Any[Int,Any], op! = Any[push!,pushfirst!], op = Any[length,size],
           xs = Any[(Int,), (Int,Int,)]
           let effects = Base.infer_effects(simple_vec_ops, (Type{T},typeof(op!),typeof(op),xs...))
               @test Core.Compiler.is_foldable(effects)
           end
       end

julia> code_typed() do
           simple_vec_ops(Any, push!, length, Any,nothing,Core.Const(1))
       end
1-element Vector{Any}:
 CodeInfo(
1 ─     return 3
) => Int64

base/array.jl

aviatesk · 2022-10-13T14:09:57Z

@nanosoldier runbenchmarks(!"scalar", vs=":master")

nanosoldier · 2022-10-13T19:59:30Z

Your benchmark job has completed - possible performance regressions were detected. A full report can be found here.

base/array.jl

base/tuple.jl

vtjnash

SGTM overall, with questions/comments

@test

Mostly by making use of newly added `:inaccessiblememonly` effect property. Now we can fold simple vector operations like: ```julia julia> function simple_vec_ops(T, op!, op, xs...) a = T[] op!(a, xs...) return op(a) end; simple_vec_ops (generic function with 1 method) julia> for T = Any[Int,Any], op! = Any[push!,pushfirst!], op = Any[length,size], xs = Any[(Int,), (Int,Int,)] let effects = Base.infer_effects(simple_vec_ops, (Type{T},typeof(op!),typeof(op),xs...)) @test Core.Compiler.is_foldable(effects) end end julia> code_typed() do simple_vec_ops(Any, push!, length, Any,nothing,Core.Const(1)) end 1-element Vector{Any}: CodeInfo( 1 ─ return 3 ) => Int64 ```

N5N3 · 2023-04-08T04:56:31Z

base/array.jl

+# safe version
+function getindex(::Type{T}, vals::T...) where T
+    @inline
+    @_effect_free_terminates_locally_meta
+    a = Vector{T}(undef, length(vals))
+    @_safeindex for i in 1:length(vals)
+        a[i] = vals[i]
+    end
+    return a
+end


@aviatesk
Is there a reason to add this? It seems unneeded and cause some new ambiguity JuliaArrays/StaticArrays.jl#1153 (comment)

I added this definition since otherwise we can't const-fold safe getindex operations due to the :nothrow effect tainted by the foldr branch in the unsafe definition.

But it looks like this definition is no longer needed (the vals isa NTuple branch is const-folded even without constant information propagated)? I will make a PR to delete this.

xref: <#47154 (comment)>

@test

) Mostly by making use of newly added `:inaccessiblememonly` effect property. Now we can fold simple vector operations like: ```julia julia> function simple_vec_ops(T, op!, op, xs...) a = T[] op!(a, xs...) return op(a) end; simple_vec_ops (generic function with 1 method) julia> for T = Any[Int,Any], op! = Any[push!,pushfirst!], op = Any[length,size], xs = Any[(Int,), (Int,Int,)] let effects = Base.infer_effects(simple_vec_ops, (Type{T},typeof(op!),typeof(op),xs...)) @test Core.Compiler.is_foldable(effects) end end julia> code_typed() do simple_vec_ops(Any, push!, length, Any,nothing,Core.Const(1)) end 1-element Vector{Any}: CodeInfo( 1 ─ return 3 ) => Int64 ```

xref: <JuliaLang#47154 (comment)>

#47154 mistakenly added `@_safeindex` macro on the `_append!(a::AbstractVector, ::Union{HasLength,HasShape}, iter)` method, although `@_safeindex` is only valid for builtin vectors i.e. `Vector`. This commit adds `isa` check so that `@_safeindex` is only applied to builtin vectors. The `isa` check should be removed at compile time, so it should not affect the runtime performance. closes #49748

aviatesk added arrays [a, r, r, a, y, s] compiler:effects effect analysis labels Oct 13, 2022

aviatesk commented Oct 13, 2022

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aviatesk force-pushed the avi/array-effects branch 2 times, most recently from 85598c2 to 6be923c Compare October 13, 2022 14:09

aviatesk force-pushed the avi/array-effects branch from 6be923c to 58294d3 Compare October 13, 2022 14:48