The union work turns out to be a lot because compiler extensions and simd<> barely support anything beyond operators. Examples of what's missing: interleaved l

The union work turns out to be a lot because compiler extensions and simd<> barely support anything beyond operators. Examples of what's missing: interleaved load/store, compress/expand, software AES/CLMUL, popcount, lzcnt, saturated add/sub, 128-bit compare/minmax, fixed-point mul, mask find/set, masked load/store, scatter/gather, reductions. Highway supports those (and >200 operations in total) on all platforms.