mmcfg has some undocumented features and I wonder if you could abuse those to get some info.
AS3DCE is a flag that can be set to 1 or 0 and I assume it defaults to 1 if not set.
(I haven't tested this btw this is a wild guess)
DCE standing for Dead Code Elimination.
Anyway I wondered if you could compile your app once with the flag set and once without. Then de-compile and diff both outputs to see if it highlights the code that was stripped.
No idea if it would work but could be worth a shot.