Doing so is not allowed (presumably because compilers are allowed to use a different algorithm for allocating between the two/store extra data such as the length of the array before the pointer).
This bug existed in the original implementation at https://web.archive.org/web/20140708092159/http://www.hydrogenaud.io/forums/index.php?showtopic=52235 and causes Valgrind to emit a warning. Note that this ended up happening even if DSPLLE and the DPL decoder are not enabled in Dolphin.