Federer, the 17-time Grand Slam champion who is seeded seventh here this year, dominated the 31st-ranked Dolgopolov, thwarting the Ukrainian's bid to become just the sixth player to beat both Rafael Nadal and Federer in the same tournament.
Federer put 72 percent of his first serves in play and didn't face break point in an efficient display before an adoring crowd at the Indian Wells Tennis Garden's stadium court.
The Swiss great will play the winner of the second semi-final between world number two and second seed Novak Djokovic and 12th-seeded American John Isner.
By reaching the semi-finals, Federer was assured of returning to the top five in the world rankings for the first time since September of 2013.
After a modest 2013 campaign that saw him win just one ATP title, the 32-year-old Swiss has opened 2014 with a title in Brisbane, reached the semi-finals at the Australian Open, and won the title in February in Dubai, where he beat Djokovic in the semi-finals.
If he wins a fifth title on Sunday to go with those he captured in 2004, 2005, 2006 and 2012, Federer will rise to number four in the world next week.
