Apologies, this is the code block that does not compile: inline constexpr uint8_t test(uint64_t value) { return __builtin_clzll(value); } -- View this message in context: http://clang-developers.42468.n3.nabble.com/constexpr-with-builtin-tp4034336p4034337.html Sent from the Clang Developers mailing list archive at Nabble.com.