As it so happens, the exporter does implement a "constant folding" optimisation. If you type the expression 100 + 100, at export time C2 can calculate this and determine it's 200, and not export an addition calculation.
However it's almost completely irrelevant to performance. Don't waste your time worrying about this.
Anything not in the performance tips manual entry probably has negligable effect. Only things likely to have any effect are mentioned in that article, so if it's not mentioned there, you most likely do not need to worry about it at all. You could optimise all the math across an entire large project, and get maybe a 0.01% performance improvement, if you could even measure that accurately. Compare that to reducing the rate of a particles object which could get you a 1% performance improvement (100x better) at almost no effort at all.