I can see how arithmetic and bitshifting is the same among all architectures. But I would think that even loads and stores have differences, at least if you want to use the processor efficiently. But he says everything kinda looks the same.
The basics are the same (and indeed that is why many RISCs resemble MIPS), but you're correct that more advanced (or perhaps I could say, Intel-ligent ;-) architectures have many more interesting instructions that are beyond the subset, and can definitely save on code speed, size, or both when used effectively but are not easy to match nor describe the semantics of. It's easy to match X+Y to an ADD, or even X = 4 * Y + C to an LEA, but at the other extreme, how would you match a whole AES encryption round and replace it with a single AESENC instruction? Currently, no compiler I know of can do that, so you must use intrinsics or pure Asm.
Yeah that's what I would have thought, but I would like to see it quantified. Does all the target-specific info give you 10% or 100% improvement? Maybe they're onto something? The simplification does sound drastic.
He does actually mention the AES instruction in the talk. I think they just have some one-offs to deal with those specific cases. I guess Go is different than C because it comes with a big standard library. They can just make sure that their standard library crypto uses the AESNES instruction, whereas C compilers have no idea what crypto library you're using.
The basics are the same (and indeed that is why many RISCs resemble MIPS), but you're correct that more advanced (or perhaps I could say, Intel-ligent ;-) architectures have many more interesting instructions that are beyond the subset, and can definitely save on code speed, size, or both when used effectively but are not easy to match nor describe the semantics of. It's easy to match X+Y to an ADD, or even X = 4 * Y + C to an LEA, but at the other extreme, how would you match a whole AES encryption round and replace it with a single AESENC instruction? Currently, no compiler I know of can do that, so you must use intrinsics or pure Asm.