Explore the intricacies of Undefined Behavior in programming and its impact on compiler optimizations in this 33-minute Black Hat conference talk. Delve into how compilers, particularly LLVM, handle erroneous actions like signed integer overflow and null pointer access. Understand the unpredictable nature of programs with Undefined Behavior and the freedom compiler writers have in generating code for such cases. Learn from speakers Mingyue Liang, Wei Liu, Kai Song, and Zekai Wu as they dissect Undefined Behavior optimizations in LLVM, revealing potential bugs that compilers may detect but not explicitly report. Gain insights into improving code quality and security by understanding these hidden compiler behaviors.