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implement operate_to!!(::BigInt, ::typeof(copy), ::T) for small int T #357

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Merged
blegat merged 2 commits into from
Apr 3, 2026
Merged

implement operate_to!!(::BigInt, ::typeof(copy), ::T) for small int T #357

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b20ebda
implement operate_to!!(::BigInt, ::typeof(copy), ::T) for small int T
nsajko Apr 1, 2026
f8a1ec3
restrict the new mutability to copy
nsajko Apr 3, 2026
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22 changes: 18 additions & 4 deletions src/implementations/BigInt.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
# Base.BigInt.

mutability(::Type{BigInt}) = IsMutable()
mutability(::Type{BigInt}, ::typeof(copy), ::Vararg{Type}) = IsMutable()

# Copied from `deepcopy_internal` implementation in Julia:
# https://github.com/JuliaLang/julia/blob/7d41d1eb610cad490cbaece8887f9bbd2a775021/base/gmp.jl#L772
Expand All @@ -17,8 +18,21 @@ mutable_copy(x::BigInt) = Base.GMP.MPZ.set(x)

promote_operation(::typeof(copy), ::Type{BigInt}) = BigInt

function operate_to!(out::BigInt, ::typeof(copy), in::BigInt)
Base.GMP.MPZ.set!(out, in)
function operate_to!(
out::BigInt,
::typeof(copy),
in::Union{Bool,Int8,Int16,Int32,Clong,UInt8,UInt16,UInt32,Culong,BigInt},
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@blegat blegat Apr 3, 2026

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Not a big fan of calling a variable in, it will make Julia parsers and interpeters trip because it's used in x in set

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@nsajko nsajko Apr 3, 2026

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I agree, however that is what the surrounding code does. So I followed the pattern for consistency.

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@blegat blegat Apr 3, 2026

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Indeed, then that's a separate issue

)
let f!
if in isa BigInt
f! = Base.GMP.MPZ.set!
elseif in isa Union{Bool,Unsigned}
f! = Base.GMP.MPZ.set_ui!
elseif in isa Signed
f! = Base.GMP.MPZ.set_si!
end
f!(out, in)
end
return out
end

Expand All @@ -28,13 +42,13 @@ operate!(::typeof(copy), x::BigInt) = x

promote_operation(::typeof(zero), ::Type{BigInt}) = BigInt

operate!(::typeof(zero), x::BigInt) = Base.GMP.MPZ.set_si!(x, 0)
operate!(::typeof(zero), x::BigInt) = operate_to!(x, copy, false)

# one

promote_operation(::typeof(one), ::Type{BigInt}) = BigInt

operate!(::typeof(one), x::BigInt) = Base.GMP.MPZ.set_si!(x, 1)
operate!(::typeof(one), x::BigInt) = operate_to!(x, copy, true)

# +

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43 changes: 43 additions & 0 deletions test/test_basics.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,49 @@ test_copy_Rational_Int() = _test_copy(Rational{Int})

test_copy_Rational_BigInt() = _test_copy(Rational{BigInt})

function test_copy_BigInt_smallint()
function example_ints(t::Type{<:Integer})
if t <: Signed
[
typemin(t),
typemin(t) + t(1),
t(-2),
t(-1),
t(0),
t(1),
t(2),
typemax(t) - t(1),
typemax(t),
]
elseif t <: Unsigned
[t(0), t(1), t(2), typemax(t) - t(1), typemax(t)]
elseif t == Bool
[false, true]
else
throw(ArgumentError("unknown type"))
end
end
@testset "`copy` small integer to `BigInt`" begin
for f! in (MA.operate_to!, MA.operate_to!!)
for typ in [Bool, Int8, Int16, Int32, UInt8, UInt16, UInt32]
for x in example_ints(typ)
@test let y = BigInt(3)
x == @inferred f!(y, copy, x)
end
@test let y = BigInt(3)
y === @inferred f!(y, copy, x)
end
let y = BigInt(3), x = typ(0), f! = f!
alloc_test(0) do
return f!(y, copy, x)
end
end
end
end
end
end
end

function _test_mutating_step_range(::Type{T}) where {T}
r = MA.MutatingStepRange(T(2), T(3), T(9))
expected = MA.mutability(T) isa MA.IsMutable ? 8 * ones(T, 3) : T[2, 5, 8]
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