I have benchmarked similar code extensively, this is a toy version of a FIX checksum. It's not "counterintuitive", it's just broken, especially for infrequentl

I have benchmarked similar code extensively, this is a toy version of a FIX checksum. It's not "counterintuitive", it's just broken, especially for infrequently executed code where the instruction fetch stalls will kill your latency. You are welcomed to load up the godbolt example and try and create better assembly using O2 or whatever else you can think of. You can build the code on your machine and benchmark it too. But at the end of the day, the compiler output sucks. It's clearly optimized for synthetic benchmarks that chug through large datasets using a tiny amount of code that can fit in L1 cache even after the compiler blows up its footprint. But my point is that these large datasets with tiny processing kernels (like a video codec for example) are much better suited to different kinds of processors.