Not sure what you mean, SIMD instructions maps perfectly well to C. You just call them like you call any other thing. What C doesn't do well are the exact CPU memory load order, how it caches things in the CPU etc. But no language can do that as you can't even control that in the machine code sent to the CPU. But most things you can do in machine code can also be done in C, and then things you can't can be done in inline assembly.
I suppose what they referred to is Java's (currently incubating) vector computation API. It lets you express vectorized algorithms in high-level way, with the API's methods being translated of the corresponding SIMD instructions of the underlying platform. I.e. you'll get vectorized execution on x86 and AArch-64 in a portable way, including transparent fallback to scalar execution if specific operations aren't supported on a specific target platform.
Right, but that would still mean that C is closer to the hardware than Java. Java has a high level but less powerful solution, since you can only use it on vectors and not arbitrary data anywhere. You can write a similar function in C which compiles differently depending on where you compile and falls back in the same way, just that C gives you the option to use the hardware dependent instructions anywhere if you want.
I’m not sure I understand you: in C there is no standard way for SIMD afaik. There are pragmas on for loops, or other compiler specific tools but the language itself don’t have any notion of lanes or SIMD instructions.
> but the language itself don’t have any notion of lanes or SIMD instructions.
C doesn't need it, you can just call CPU instructions like functions. SIMD is just another kind of CPU instruction, so C supports it. That works in C since you have a direct view of the memory layout. It doesn't work in higher level languages where memory is abstracted away from you, in those you need the higher level concepts you are talking about in order to take advantage of SIMD.
These instructions are ISA specific though; i.e. in C you'd have to implement your solution once using x86 SIMD instructions and once using the AArch64 counterparts. You'd also have to account for different vector lengths. Whereas the Java API does all that for you automatically, e.g. automatically taking advantage of longer vectors when running on AVX512, and shorter ones elsewhere.
I think that's what people consider "better" about the Java approach (at least I do). That's of course not to say that you cannot do all this in C as well, but I think having these capabilities in that portable way available in Java makes SIMD useable for a huge audience for the first time which didn't consider that a realistic option before.
