Compiler Can Undo Your Security Checks

Compiler optimizations can remove security protections from C code that appears secure, introducing vulnerabilities such as deleted memory-clearing operations and time-of-check to time-of-use flaws into the final binary. Security researcher Chris Domas explains that factors like register pressure and data size affect whether optimized code is vulnerable, and that developers can mitigate risks by enabling compiler warnings, using sanitizers, and testing the exact binary that will be shipped.