[hdhzy]

I don't know your experiences but the "performance optimizations" that I've seen lacked obvious technical support around it. Usually people thought "it will be faster" without using profiler (sin no 1) or did not properly isolate and control the performance critical part of the code (making performance tests part of the build etc.). But these are other issues separate from optimizing code.

The usual caveat of making code correct, readable and then fast in this order of course also applies :)