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Fix type instability in convs using CompoundPeriod#54995

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aviatesk merged 2 commits intoJuliaLang:masterfrom
ronisbr:compound_period_type_stability
Jul 14, 2024
Merged

Fix type instability in convs using CompoundPeriod#54995
aviatesk merged 2 commits intoJuliaLang:masterfrom
ronisbr:compound_period_type_stability

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@ronisbr
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@ronisbr ronisbr commented Jul 1, 2024

The functions toms, tons, and days uses sum over a vector of Periods to obtain the conversion of a CompoundPeriod. However, the compiler cannot infer the return type because those functions can return either Int or Float depending on the type of the Period. This PR forces the result of those functions to be Float64, fixing the type stability.

Before this PR we had:

julia> using Dates

julia> p = Dates.Second(1) + Dates.Minute(1) + Dates.Year(1)
1 year, 1 minute, 1 second

julia> @code_warntype Dates.tons(p)
MethodInstance for Dates.tons(::Dates.CompoundPeriod)
  from tons(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:458
Arguments
  #self#::Core.Const(Dates.tons)
  c::Dates.CompoundPeriod
Body::Any
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.tons::Core.Const(Dates.tons)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
└──       return %11


julia> @code_warntype Dates.toms(p)
MethodInstance for Dates.toms(::Dates.CompoundPeriod)
  from toms(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:454
Arguments
  #self#::Core.Const(Dates.toms)
  c::Dates.CompoundPeriod
Body::Any
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.toms::Core.Const(Dates.toms)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
└──       return %11


julia> @code_warntype Dates.days(p)
MethodInstance for Dates.days(::Dates.CompoundPeriod)
  from days(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:468
Arguments
  #self#::Core.Const(Dates.days)
  c::Dates.CompoundPeriod
Body::Any
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.days::Core.Const(Dates.days)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
└──       return %11

After this PR we have:

julia> using Dates

julia> p = Dates.Second(1) + Dates.Minute(1) + Dates.Year(1)
1 year, 1 minute, 1 second

julia> @code_warntype Dates.tons(p)
MethodInstance for Dates.tons(::Dates.CompoundPeriod)
  from tons(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:458
Arguments
  #self#::Core.Const(Dates.tons)
  c::Dates.CompoundPeriod
Body::Float64
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.tons::Core.Const(Dates.tons)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
│   %12 = Dates.Float64::Core.Const(Float64)
│   %13 = Core.typeassert(%11, %12)::Float64
└──       return %13


julia> @code_warntype Dates.toms(p)
MethodInstance for Dates.toms(::Dates.CompoundPeriod)
  from toms(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:454
Arguments
  #self#::Core.Const(Dates.toms)
  c::Dates.CompoundPeriod
Body::Float64
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.toms::Core.Const(Dates.toms)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
│   %12 = Dates.Float64::Core.Const(Float64)
│   %13 = Core.typeassert(%11, %12)::Float64
└──       return %13


julia> @code_warntype Dates.days(p)
MethodInstance for Dates.days(::Dates.CompoundPeriod)
  from days(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:468
Arguments
  #self#::Core.Const(Dates.days)
  c::Dates.CompoundPeriod
Body::Float64
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.days::Core.Const(Dates.days)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
│   %12 = Dates.Float64::Core.Const(Float64)
│   %13 = Core.typeassert(%11, %12)::Float64
└──       return %13

@ronisbr
Fix type instability in convs using CompoundPeriod
a75884f 
The functions `toms`, `tons`, and `days` uses `sum` over a vector of
`Period`s to obtain the conversion of a `CompoundPeriod`. However, the
compiler cannot infer the return type because those functions can return
either `Int` or `Float` depending on the type of the `Period`. This PR
forces the result of those functions to be `Float64`, fixing the type
stability.
aviatesk
aviatesk reviewed Jul 2, 2024
View reviewed changes
@dkarrasch dkarrasch added dates Dates, times, and the Dates stdlib module compiler:inference Type inference labels Jul 2, 2024
@ronisbr
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ronisbr commented Jul 6, 2024

Bump!

@ronisbr
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ronisbr commented Jul 13, 2024

Bump 2!

@oscardssmith
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oscardssmith commented Jul 14, 2024

looks reasonable to me. (this likely didn't receive attention because everyone was busy with JuliaCon last week)

@aviatesk aviatesk merged commit e496b2e into JuliaLang:master Jul 14, 2024
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aviatesk commented Jul 14, 2024

Thanks for your contribution, @ronisbr !

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@ronisbr @oscardssmith @aviatesk @dkarrasch