Fix reorder to avoid eval on copied array instead of input array

The reorder funciton was copying the Array object internally and
then the other operations were performed on the copy. This causes
the eval to be performed on the copied array instead of the input
array.

src/api/c/reorder.cpp

@@ -33,12 +33,14 @@ using std::swap;
 
 template<typename T>
 static inline af_array reorder(const af_array in, const af::dim4 &rdims0) {
-    Array<T> In = getArray<T>(in);
+    Array<T> In = detail::createEmptyArray<T>(af::dim4(0));
     dim4 rdims  = rdims0;
 
     if (rdims[0] == 1 && rdims[1] == 0) {
-        In = transpose(In, false);
+        In = transpose(getArray<T>(in), false);
         std::swap(rdims[0], rdims[1]);
+    } else {
+        In = getArray<T>(in);
     }
     const dim4 idims    = In.dims();
     const dim4 istrides = In.strides();
@@ -48,8 +50,7 @@ static inline af_array reorder(const af_array in, const af::dim4 &rdims0) {
 
     af_array out;
     if (rdims[0] == 0 && rdims[1] == 1 && rdims[2] == 2 && rdims[3] == 3) {
-        const Array<T> &Out = In;
-        out                 = getHandle(Out);
+        out = getHandle(In);
     } else if (rdims[0] == 0) {
         dim4 odims    = dim4(1, 1, 1, 1);
         dim4 ostrides = dim4(1, 1, 1, 1);