People occasionally ask why LLVM-compiled code sometimes generates SIGTRAP signals when the optimizer is turned on. After digging in, they find that Clang generated a "ud2" instruction (assuming X86 code) - the same as is generated by __builtin_trap().| The LLVM Project Blog
We're bad at marketing| lwn.net
UndefinedBehaviorSanitizer¶| clang.llvm.org