Andrew Gallagher enhanced AddressSanitizer reliability in the espressif/llvm-project repository by implementing suppression for allocation-deallocation mismatch errors. He introduced a dedicated suppression type and stack-based logic in C++ to identify and suppress these mismatches, reducing false positives and improving memory safety diagnostics. Andrew expanded end-to-end test coverage to verify the new suppression behavior, ensuring that future changes would not introduce regressions. His work focused on compiler development and debugging tools, directly addressing CI stability and developer productivity. By linking changes to specific commits and strengthening sanitizer tests, Andrew delivered a targeted, maintainable solution that improved the debugging experience for developers.