Explore the impact of compiler optimizations on software security in this 45-minute conference talk from AppSec EU 2017. Delve into how compiler writers leverage undefined behaviors in C and C++ to enhance optimizations, potentially compromising developers' ability to perform cause-effect analysis. Examine common optimizations, their potential to introduce software vulnerabilities, and learn practical mitigation strategies. Cover topics such as constant folding, bounds checking, algebraic simplification, and critical undefined behaviors. Gain insights into GCC details, strict overflow settings, and recommendations for maintaining software causality and reducing the risk of faults, defects, and vulnerabilities in C and C++ programming.