No support for AVX2. AVX-512 is the first really nice (from the programmer's perspective) SIMD instruction set on x86-64 CPUs, and it's significantly different

No support for AVX2. AVX-512 is the first really nice (from the programmer's perspective) SIMD instruction set on x86-64 CPUs, and it's significantly different from what came before. AVX-512 is not just a wider version of AVX2 NN-512 explores the way Winograd and Fourier convolutions can be done when you have 32 512-bit vector registers. Four 8x8 Winograd tiles simultaneously, four 8x8 Fourier tiles interleaved to form a 16x16 tile for strided convolutions, and so on. These multi-tile operations don't work for AVX2, too few registers, each register too narrow GCC has only very recently come into a state where it properly supports AVX-512. For example, before GCC 9.1, GCC would split FNMADD into xor-negation followed by FMADD (doing an extra xor, using an extra register for the negation constant, instead of just using the FNMADD instruction). Eventually the hardware will mature, too