Comment by Aeyxen

Many variants of this debate play out in real-world systems: data pipelines, game engines, and large-scale web infra. The only universal law is that local code clarity must never be optimized at the expense of global throughput or maintainability. Pushing ifs up absolutely unlocks performance when you're dealing with a hot loop—early bailouts mean less work per iteration, and in my experience, that's often the difference between a scalable system and a bottleneck. But the real win is batch processing (pushing fors down): it's the only way you get cache locality, vectorization, and real-world performance on modern hardware. No amount of OOP purity or DRY dogma can change the physics of memory bandwidth or the nature of branch misprediction.