There’s no easy and obvious way that I could find to download all the songs in iTunes Match (previously purchased, matched, and uploaded) onto an iPhone with iOS 6. (The iTunes app can download only previously purchased songs. This may also apply to iPads.) The way to do it is to create a playlist of all your music, then scroll to the bottom and tap the download button. Simple, but not discoverable. It’s shameful that the solution is so indirect.