re-add unsafe_convert for Reinterpret and Reshaped array (#55226)

Fxes #54725

Author: oscardssmith

base/reinterpretarray.jl

@@ -373,6 +373,7 @@ has_offset_axes(a::ReinterpretArray) = has_offset_axes(a.parent)
 
 elsize(::Type{<:ReinterpretArray{T}}) where {T} = sizeof(T)
 cconvert(::Type{Ptr{T}}, a::ReinterpretArray{T,N,S} where N) where {T,S} = cconvert(Ptr{S}, a.parent)
+unsafe_convert(::Type{Ptr{T}}, a::ReinterpretArray{T,N,S} where N) where {T,S} = Ptr{T}(unsafe_convert(Ptr{S},a.parent))
 
 @propagate_inbounds function getindex(a::NonReshapedReinterpretArray{T,0,S}) where {T,S}
     if isprimitivetype(T) && isprimitivetype(S)

base/reshapedarray.jl

@@ -324,6 +324,7 @@ setindex!(A::ReshapedRange, val, index::ReshapedIndex) = _rs_setindex!_err()
 @noinline _rs_setindex!_err() = error("indexed assignment fails for a reshaped range; consider calling collect")
 
 cconvert(::Type{Ptr{T}}, a::ReshapedArray{T}) where {T} = cconvert(Ptr{T}, parent(a))
+unsafe_convert(::Type{Ptr{T}}, a::ReshapedArray{T}) where {T} = unsafe_convert(Ptr{T}, a.parent)
 
 # Add a few handy specializations to further speed up views of reshaped ranges
 const ReshapedUnitRange{T,N,A<:AbstractUnitRange} = ReshapedArray{T,N,A,Tuple{}}

test/ccall.jl

@@ -1937,7 +1937,10 @@ end
 
 # issue #52025
 @test Base.unsafe_convert(Ptr{Ptr{Cchar}}, Base.cconvert(Ptr{Ptr{Cchar}}, map(pointer, ["ab"]))) isa Ptr{Ptr{Cchar}}
-
+#issue #54725
+for A in (reinterpret(UInt, [0]), reshape([0, 0], 1, 2))
+    @test pointer(A) == Base.unsafe_convert(Ptr{Cvoid}, A) == Base.unsafe_convert(Ptr{Int}, A)
+end
 # Cglobal with non-static symbols doesn't error
 function cglobal_non_static1()
     sym = (:global_var, libccalltest)