[yoklov]

Again, inline ASM is pretty rare these days (when we do use it, it isn't for SIMD). Intrinsics are much more common.

The big issue (aside from convincing MSVC to implement it ;) with your suggestion is that, unlike TCO, vectorization isn't really a boolean. There's a range of what vectorization might mean (you can vectorize code and do a bad job with it, only marginally beating out the scalar code), so you'd still need to check the generated code for the situations where you care.

And honestly, it's not worth the effort. Vectorization shouldn't be as scary as it is for most programmers. Once you get the hang of how to do it, it's not bad at all. We write a lot of SIMD code at work, and 'difficulty of writing SIMD code' isn't a big issue for us. Honestly, it's kind of fun, a bit like solving a puzzle (an optimization puzzle, something like SpaceChem or Infinifactory).

Now, a situation where it might be a win is if you have a lot of different platforms you need vectorized code for... but in my experience you're probably better off doing it by hand unless this is a huge number.

[blt]

Writing SSE code using compiler intrinsics is indeed a fun puzzle, but it has huge drawbacks: 1) it's Intel-specific, and 2) it's a maintenance risk unless everyone in the shop knows how to write and maintain SSE code. Unfortunately nobody else at my job knows how to do it, so I am not allowed to check any in :(

[yoklov]

> it's Intel-specific

Most platforms offer intrinsics.

> it's a maintenance risk unless everyone in the shop knows how to write and maintain SSE code.

This is understandable, but not the case where I work. If you need to be writing SIMD code and this is the case, then you need to hire programmers who can do it. That or convince them to learn, as (again) it's not that hard.