I have a 14 Amp Ryobi miter saw. In the manual it has a table for required AWG by Cord Length and Amps. For 100' and 12.1-16.0 Amps it just has a dash indicating there is no suitable AWG extension cable for this length and amp combination.
How much cutting are you actually going to be doing? This is going to be key. The resistance on a smaller wire (larger gage number) and longer length is going to turn the cord hot. But if you're making 3 cuts, I wouldn't worry about it. If you are going to run it 24/7, then I'd worry.
Run it for a few days at the expected use amount and keep an eye on the heat of the cord but also the outlet and plug. I do have to say that 100' is a lot. No outlets closer than that to you?