It is not OK to just randomly avoid doing optimizations allowed by the C standard because they might trigger bugs. C depends on undefined behavior for performan

It is not OK to just randomly avoid doing optimizations allowed by the C standard because they might trigger bugs. C depends on undefined behavior for performance. You depend on these compiler optimizations to get good performance out of the programs you run every day. Geoff offers a simple succinct example of optimizing based on undefined behavior in another comment in this thread: https://news.ycombinator.com/item?id=11147068 https://news.ycombinator.com/item?id=11147068 I tested with GCC, Clang, MSVC, and ICC, and found that only GCC removed the checks and optimized the function down to a constant. Clang, MSVC, and ICC instead generated code that matched the programmer's clear intent. Are you sure they would be better compilers if they matched GCC's behavior here? I agree the GCC authors are far from stupid, but I think there might be a difference in philosophy here rather than just a missed opportunity for optimization.