Your Bitmask Is Probably Dead Code. Here’s Why Your JIT Already Knows.
HotSpot’s JIT uses known-bits analysis to statically eliminate redundant bitmask operations, turning carefully written defensive code into no-ops at runtime. Most developers assume their bitwise operations always execute, but this optimization reveals the gap between human coding and machine reasoning. The takeaway: trust your JIT, profile before micro-optimizing, and write for clarity first.