Toolchain support, at the minimum, often consists of having a compiler flag to allow the use of intrinsics for the new architecture - pretty much the opposite o

Toolchain support, at the minimum, often consists of having a compiler flag to allow the use of intrinsics for the new architecture - pretty much the opposite of what you're hoping (automagical support). There's a fair bit of work where people try to autovectorize code. I'm happy that folks are pushing this work, but, well, I drive a manual (in this regard). It does happen that code does auto-detection and skips to a particularly compelling platform-specific optimization path, but it's a huge pain. It's unlikely that someone will optimize for each and every variant, but they might draw a line here and there through the myriad of architecture choices and offer something. Sorry that the story isn't better. I generally hand-code stuff - not in asm but with intrinsics (which is getting a lot of the benefit of asm, but without doing all your own codegen for the boring bits, scheduling and register allocation).