Results of optimizations vary widely with different languages, compilers, and environments. Without measuring each specific optimization, you'll have no idea whether it will help or hurt your program.

The first optimization is often not the best. Even after you find a good one, keep looking for one that's better.

Code tuning is a little like nuclear energy. It's a controversial, emotional topic. Some people think it's so detrimental to reliability and maintainability that they won't do it at all. Others think that with proper safeguards, it's beneficial. If you decide to use the techniques in this chapter, apply them with care.