add inttype, floattype like uinttype (JuliaLang#36526)

Author: JeffreySarnoff

base/float.jl

@@ -962,6 +962,17 @@ bswap(x::IEEEFloat) = bswap_int(x)
 uinttype(::Type{Float64}) = UInt64
 uinttype(::Type{Float32}) = UInt32
 uinttype(::Type{Float16}) = UInt16
+inttype(::Type{Float64}) = Int64
+inttype(::Type{Float32}) = Int32
+inttype(::Type{Float16}) = Int16
+# float size of integer
+floattype(::Type{UInt64}) = Float64
+floattype(::Type{UInt32}) = Float32
+floattype(::Type{UInt16}) = Float16
+floattype(::Type{Int64}) = Float64
+floattype(::Type{Int32}) = Float32
+floattype(::Type{Int16}) = Float16
+
 
 ## Array operations on floating point numbers ##