Bit late to mention it here, but GCC Explorer now supports GCC 5.1, and in fact has done since the day it was released!
GCC 5.1 has a bunch of link-time optimizations that aren’t well-demonstrated by GCC Explorer, so I’m going to have to revamp it a little. Watch this space!
Matt Godbolt is a C++ developer living in Chicago. Follow him on Mastodon or Bluesky.