No it will not! I thought it would, but I just barely did this about a week ago, and can confirm it does not delete the music on your iPhone.
When you sync songs to your iPhone so they are stored locally, taking up space on your iPhone, then you go and enable iTunes Match, it will not delete anything from your phone. The text says it will "replace" your library with that of iCloud (which is true), but you can be sure it does not screw anything up.
This allows you to not have to stream music, as they are still stored locally, but it does update metadata over iCloud. So when you change a name of a song on your Mac, it is changed on your iPhone near instantly, and it works pretty well! You no longer have to plug your iPhone in and sync.