What Every C Programmer Should Know About Undefined Behavior #1/3What Every C Programmer Should Know About Undefined Behavior #1/3 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(). There are several issues at work here, all centering around undefined behavior in
