Do minifiers typically strip dead code? Beyond removing whitespace and unnecessary semicolons, I know they rewrite some if statements into confusing?alternative

Do minifiers typically strip dead code? Beyond removing whitespace and unnecessary semicolons, I know they rewrite some if statements into confusing?alternative:formats that save bytes but do the same thing, but really cutting parts out? Obviously less non-whitespace data to parse will make the parsing faster, but I would be curious whether it bothers trying to detect dead code. It seems similar to a halting problem, knowing whether something can be reached, but I'm not well-versed enough in that theory to really say much more than this gut feeling.