Branch Prediction Hints in Order Validation - Quant Developer Interview Question

Problem Description

In ultra-low latency trading systems, minimizing CPU cycles is critical, often achieved by optimizing branch prediction to prevent costly pipeline flushes. C++20 attributes like likely allow developers to hint to the compiler which execution paths are most probable, enabling memory layout optimizations that favor the "happy path." This technique is particularly useful in pre-trade risk checks where the vast majority of orders are expected to be valid and should be processed as quickly as possibl