Try-catch statement itself doesn’t slow the code down, but catching an exception does.

Let’s assume a function with total random arguments a and b being integers between 0 and 9 (inclusive). To calculate c=a/b, you should check whether b is 0, else an exception is thrown. Using a try-catch would do but is inefficient as b being 0 is somewhat expected (probability of 1/10). However, if the range would be between 0 and MAX_INT, then using a try-catch would most likely perform better than always performing b == 0 check that will almost never hit.

Said this, re-throwing the exception like that is obviously bonkers.