Specialize _memory_offset on number of arguments. (#37444)

Author: chriselrod

base/abstractarray.jl

@@ -1070,8 +1070,8 @@ function pointer(x::AbstractArray{T}, i::Integer) where T
 end
 
 # The distance from pointer(x) to the element at x[I...] in bytes
-_memory_offset(x::DenseArray, I...) = (_to_linear_index(x, I...) - first(LinearIndices(x)))*elsize(x)
-function _memory_offset(x::AbstractArray, I...)
+_memory_offset(x::DenseArray, I::Vararg{Any,N}) where {N} = (_to_linear_index(x, I...) - first(LinearIndices(x)))*elsize(x)
+function _memory_offset(x::AbstractArray, I::Vararg{Any,N}) where {N}
     J = _to_subscript_indices(x, I...)
     return sum(map((i, s, o)->s*(i-o), J, strides(x), Tuple(first(CartesianIndices(x)))))*elsize(x)
 end