#ifndef AVX512_FUNCS_H

#define AVX512_FUNCS_H

#include <immintrin.h>

#include <stdint.h>

/* Written because Visual C++ toolchains before v142 have constant overflow in AVX512 intrinsic macros */

#if defined(_MSC_VER) && !defined(_MM_K0_REG8)

#  undef _mm512_extracti64x4_epi64

#  define _mm512_extracti64x4_epi64(v1, e1) _mm512_maskz_extracti64x4_epi64(UINT8_MAX, v1, e1)

#  undef _mm512_set1_epi16

#  define _mm512_set1_epi16(e1) _mm512_maskz_set1_epi16(UINT32_MAX, e1)

#  undef _mm512_maddubs_epi16

#  define _mm512_maddubs_epi16(v1, v2) _mm512_maskz_maddubs_epi16(UINT32_MAX, v1, v2)

#endif

/* Written because *_add_epi32(a) sets off ubsan */

static inline uint32_t _mm512_reduce_add_epu32(__m512i x) {

    __m256i a = _mm512_extracti64x4_epi64(x, 1);

    __m256i b = _mm512_extracti64x4_epi64(x, 0);

    __m256i a_plus_b = _mm256_add_epi32(a, b);

    __m128i c = _mm256_extracti128_si256(a_plus_b, 1);

    __m128i d = _mm256_extracti128_si256(a_plus_b, 0);

    __m128i c_plus_d = _mm_add_epi32(c, d);

    __m128i sum1 = _mm_unpackhi_epi64(c_plus_d, c_plus_d);

    __m128i sum2 = _mm_add_epi32(sum1, c_plus_d);

    __m128i sum3 = _mm_shuffle_epi32(sum2, 0x01);

    __m128i sum4 = _mm_add_epi32(sum2, sum3);

    return _mm_cvtsi128_si32(sum4);

}

Unexecuted instantiation: adler32_avx512.c:_mm512_reduce_add_epu32

Unexecuted instantiation: adler32_avx512_vnni.c:_mm512_reduce_add_epu32

static inline uint32_t partial_hsum(__m512i x) {

    /* We need a permutation vector to extract every other integer. The

     * rest are going to be zeros. Marking this const so the compiler stands

     * a better chance of keeping this resident in a register through entire

     * loop execution. We certainly have enough zmm registers (32) */

    const __m512i perm_vec = _mm512_setr_epi32(0, 2, 4, 6, 8, 10, 12, 14,

                                               1, 1, 1, 1, 1,  1,  1,  1);

    __m512i non_zero = _mm512_permutexvar_epi32(perm_vec, x);

    /* From here, it's a simple 256 bit wide reduction sum */

    __m256i non_zero_avx = _mm512_castsi512_si256(non_zero);

    /* See Agner Fog's vectorclass for a decent reference. Essentially, phadd is

     * pretty slow, much slower than the longer instruction sequence below */

    __m128i sum1  = _mm_add_epi32(_mm256_extracti128_si256(non_zero_avx, 1),

                                  _mm256_castsi256_si128(non_zero_avx));

    __m128i sum2  = _mm_add_epi32(sum1,_mm_unpackhi_epi64(sum1, sum1));

    __m128i sum3  = _mm_add_epi32(sum2,_mm_shuffle_epi32(sum2, 1));

    return (uint32_t)_mm_cvtsi128_si32(sum3);

}

Unexecuted instantiation: adler32_avx512.c:partial_hsum

Unexecuted instantiation: adler32_avx512_vnni.c:partial_hsum

#endif