As of May 2019, Phoronix showed them being roughly equal, with the winner depending on the application. https://www.phoronix.com/scan.php?page=article&item=gcc9

As of May 2019, Phoronix showed them being roughly equal, with the winner depending on the application. https://www.phoronix.com/scan.php?page=article&item=gcc9-clang8-hedt&num=3 https://www.phoronix.com/scan.php?page=article&item=gcc9-cla... We should expect them to both continue to improve. It's not a sure thing that Clang will end up the clear winner.