The article is spot on about SIMD. Often, if you can write your code in exactly the specific form that you would if you were using intrinsics, the compiler will

The article is spot on about SIMD. Often, if you can write your code in exactly the specific form that you would if you were using intrinsics, the compiler will go ahead and SIMDify for you. But you have essentially a 0% chance of writing in that form unless you already have experience writing SIMD code! Things like branches, loop termination not being regular, alignment, aliasing, function calls, etc all can and do stop your otherwise totally amenable code from vectorizing. In the terminology of the article, I'm still at Phase 2. By the time I've worked out the dataflow and constraints needed to make a loop parallelize, I've more or less converted it into the form needed for intrinsics already, so why not write them and be sure. More broadly, the biggest impact I've seen using MSVC (which most of my code is written in), is the function inliner makes absolutely terrible decisions, particularly with lambdas, which is really unfortunate because there's no way to force-inline the lambda. Combine that with the above - the presence of the lambda will prevent vectorization, even though if it was inlined it would then be trivially vectorizable. :(