I believe it strips the comments. And I also believe that it depends upon the accelerator. Some may use only one line, others may strip white-space, others may strip everything, others may just obfuscate your code and run that way.
To be truthfully honest, I have yet to see a reason to use an accelerator, unless your application uses 1 file that is 2,000,000,000,000 lines long. It seems a little redundant for those extra 0.02 seconds.