[muth02446]

RE: unexpected performance degradation

programs can be quite sensitive to how code is laid out because of cache line alignment, cache conflicts etc.

So random changes can have a surprising impact.

There was a paper a couple of years ago explaining this and how to measure compiler optimizations more reliably. Sadly, I do not recall the title/author.

[Arech]

It would be super interesting to read the paper. Please post a link or some more details if you will remember them.