--  #define sizzeofMutableByteArrayzh(r,a) \
--      r = ((StgArrWords *)(a))->bytes
emitPrimOp dflags [res] SizeofMutableByteArrayOp [arg]
   = emitPrimOp dflags [res] SizeofByteArrayOp [arg]
emitPrimOp dflags [res] SizeofMutableByteArrayOp [arg]
   = emitPrimOp dflags [res] SizeofByteArrayOp [arg]
emitPrimOp dflags [res] SizeofMutableByteArrayOp [arg]
   = emitPrimOp dflags [res] SizeofByteArrayOp [arg]