[noelwelsh]

My understanding is that automatic vectorization is still quite sensitive to how code is written. The compiler may fail to vectorize one implementation of an algorithm, while vectorize another, due to details in the implementation of both the code and the compiler.

My point is not about vectorization though. Code that uses mostly vectors, math, and function calls has a very direct translation to machine code. I expect all compilers to generate approximately the same machine code for this type of code, assuming vectorization doesn't come into play. So I don't expect to see large differences in performance. Of course there will be some difference, but not the order of magnitude one sees between compiled (statically or JITed) languages and interpreted languages.

[sampo]

> assuming vectorization doesn't come into play.

Now that 256 bit AVX registers that process 4 numbers in one go, even when one uses 64bit floats (and 8 with 32bit floats), vectorization more and more comes into play.

Using 64bit floats with 128bit SSE registers, it was kinda possible to ignore the vectorization, as it was less than 2x speedup. But no more.