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convert ARM NEON to WASM SIMD prompt

Raw

FAQ.md

Why did you do this?

Relax, I only have one Sunday to work on idea, literally my weekend project. So I tried Deepseek to see if it can help. Surprisingly, it works and it saves me another weekend...

What is your setup?

Just chat.deepseek.com (cost = free) with prompts adapted from this gist.

Does it work in one-shot or I have to prompt it multiple times?

For the qX_0 variants, they are actually quite straight-forward so deepseek can come up with a correct result in 1 shot.
For the qX_K it's more complicated, I would say most of the time I need to re-prompt it 4 to 8 more times.
The most difficult was q6_K, the code never works until I ask it to only optimize one specific part, while leaving the rest intact (so it does not mess up everything)

It only does conversion ARM NEON --> WASM SIMD, or it can invent new WASM SIMD code from scratch?

It can do both. For qX_0 I asked it to convert, and for qX_K I asked it to invent new code.

How much time does it spent to think?

Around 3-5 minutes per response.

Prompt is very long, what to do?

You can condense the prompt to this format, then create a new conversation (see example at the bottom):

Problem description
"Here is your last failed attempt, improve from this: [paste the last generated code here]"

Raw

prompt.md

Your task is to convert a given C++ ARM NEON SIMD to WASM SIMD. Here is an example of another function:

void ggml_vec_dot_q5_0_q8_0(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
    const int qk = QK8_0;
    const int nb = n / qk;

    int ib = 0;
    float sumf = 0;

    assert(n % qk == 0);
    assert(qk == QK5_0);
    assert(nrc == 1);
    UNUSED(nrc);
    UNUSED(bx);
    UNUSED(by);
    UNUSED(bs);

    const block_q5_0 * restrict x = vx;
    const block_q8_0 * restrict y = vy;

#if defined(__ARM_NEON)
    float32x4_t sumv0 = vdupq_n_f32(0.0f);
    float32x4_t sumv1 = vdupq_n_f32(0.0f);

    uint32_t qh0;
    uint32_t qh1;

    uint64_t tmp0[4];
    uint64_t tmp1[4];

    for (; ib + 1 < nb; ib += 2) {
        const block_q5_0 * restrict x0 = &x[ib];
        const block_q5_0 * restrict x1 = &x[ib + 1];
        const block_q8_0 * restrict y0 = &y[ib];
        const block_q8_0 * restrict y1 = &y[ib + 1];

        const uint8x16_t m4b = vdupq_n_u8(0x0F);

        // extract the 5th bit via lookup table ((!b) << 4)
        memcpy(&qh0, x0->qh, sizeof(qh0));
        memcpy(&qh1, x1->qh, sizeof(qh1));

        tmp0[0] = table_b2b_1[(qh0 >>  0) & 0xFF];
        tmp0[1] = table_b2b_1[(qh0 >>  8) & 0xFF];
        tmp0[2] = table_b2b_1[(qh0 >> 16) & 0xFF];
        tmp0[3] = table_b2b_1[(qh0 >> 24)       ];

        tmp1[0] = table_b2b_1[(qh1 >>  0) & 0xFF];
        tmp1[1] = table_b2b_1[(qh1 >>  8) & 0xFF];
        tmp1[2] = table_b2b_1[(qh1 >> 16) & 0xFF];
        tmp1[3] = table_b2b_1[(qh1 >> 24)       ];

        const int8x16_t qhl0 = vld1q_s8((const int8_t *)(tmp0 + 0));
        const int8x16_t qhh0 = vld1q_s8((const int8_t *)(tmp0 + 2));
        const int8x16_t qhl1 = vld1q_s8((const int8_t *)(tmp1 + 0));
        const int8x16_t qhh1 = vld1q_s8((const int8_t *)(tmp1 + 2));

        const uint8x16_t v0_0 = vld1q_u8(x0->qs);
        const uint8x16_t v0_1 = vld1q_u8(x1->qs);

        // 4-bit -> 8-bit
        int8x16_t v0_0l = vreinterpretq_s8_u8(vandq_u8  (v0_0, m4b));
        int8x16_t v0_0h = vreinterpretq_s8_u8(vshrq_n_u8(v0_0, 4));
        int8x16_t v0_1l = vreinterpretq_s8_u8(vandq_u8  (v0_1, m4b));
        int8x16_t v0_1h = vreinterpretq_s8_u8(vshrq_n_u8(v0_1, 4));

        // add high bit and sub 16 (equivalent to sub 0x10 when bit is zero)
        const int8x16_t v0_0lf = vsubq_s8(v0_0l, qhl0);
        const int8x16_t v0_0hf = vsubq_s8(v0_0h, qhh0);
        const int8x16_t v0_1lf = vsubq_s8(v0_1l, qhl1);
        const int8x16_t v0_1hf = vsubq_s8(v0_1h, qhh1);

        // load y
        const int8x16_t v1_0l = vld1q_s8(y0->qs);
        const int8x16_t v1_0h = vld1q_s8(y0->qs + 16);
        const int8x16_t v1_1l = vld1q_s8(y1->qs);
        const int8x16_t v1_1h = vld1q_s8(y1->qs + 16);

        sumv0 = vmlaq_n_f32(sumv0, vcvtq_f32_s32(vaddq_s32(
                        ggml_vdotq_s32(vdupq_n_s32(0), v0_0lf, v1_0l),
                        ggml_vdotq_s32(vdupq_n_s32(0), v0_0hf, v1_0h))), GGML_FP16_TO_FP32(x0->d)*GGML_FP16_TO_FP32(y0->d));
        sumv1 = vmlaq_n_f32(sumv1, vcvtq_f32_s32(vaddq_s32(
                        ggml_vdotq_s32(vdupq_n_s32(0), v0_1lf, v1_1l),
                        ggml_vdotq_s32(vdupq_n_s32(0), v0_1hf, v1_1h))), GGML_FP16_TO_FP32(x1->d)*GGML_FP16_TO_FP32(y1->d));
    }

    sumf = vaddvq_f32(sumv0) + vaddvq_f32(sumv1);
#elif defined(__wasm_simd128__)
    v128_t sumv = wasm_f32x4_splat(0.0f);

    uint32_t qh;
    uint64_t tmp[4];

    // TODO: check if unrolling this is better
    for (; ib < nb; ++ib) {
        const block_q5_0 * restrict x0 = &x[ib];
        const block_q8_0 * restrict y0 = &y[ib];

        const v128_t m4b  = wasm_i8x16_splat(0x0F);

        // extract the 5th bit
        memcpy(&qh, x0->qh, sizeof(qh));

        tmp[0] = table_b2b_1[(qh >>  0) & 0xFF];
        tmp[1] = table_b2b_1[(qh >>  8) & 0xFF];
        tmp[2] = table_b2b_1[(qh >> 16) & 0xFF];
        tmp[3] = table_b2b_1[(qh >> 24)       ];

        const v128_t qhl = wasm_v128_load(tmp + 0);
        const v128_t qhh = wasm_v128_load(tmp + 2);

        const v128_t v0 = wasm_v128_load(x0->qs);

        // 4-bit -> 8-bit
        const v128_t v0l = wasm_v128_and (v0, m4b);
        const v128_t v0h = wasm_u8x16_shr(v0, 4);

        // add high bit and sub 16 (equivalent to sub 0x10 when bit is zero)
        const v128_t v0lf = wasm_i8x16_sub(v0l, qhl);
        const v128_t v0hf = wasm_i8x16_sub(v0h, qhh);

        // load y
        const v128_t v1l = wasm_v128_load(y0->qs);
        const v128_t v1h = wasm_v128_load(y0->qs + 16);

        // int8x16 -> int16x8
        const v128_t v0lfl = wasm_i16x8_extend_low_i8x16 (v0lf);
        const v128_t v0lfh = wasm_i16x8_extend_high_i8x16(v0lf);
        const v128_t v0hfl = wasm_i16x8_extend_low_i8x16 (v0hf);
        const v128_t v0hfh = wasm_i16x8_extend_high_i8x16(v0hf);

        const v128_t v1ll = wasm_i16x8_extend_low_i8x16 (v1l);
        const v128_t v1lh = wasm_i16x8_extend_high_i8x16(v1l);
        const v128_t v1hl = wasm_i16x8_extend_low_i8x16 (v1h);
        const v128_t v1hh = wasm_i16x8_extend_high_i8x16(v1h);

        // dot product
        sumv = wasm_f32x4_add(sumv, wasm_f32x4_mul(wasm_f32x4_convert_i32x4(
                        wasm_i32x4_add(
                            wasm_i32x4_add(wasm_i32x4_dot_i16x8(v0lfl, v1ll),
                                           wasm_i32x4_dot_i16x8(v0lfh, v1lh)),
                            wasm_i32x4_add(wasm_i32x4_dot_i16x8(v0hfl, v1hl),
                                           wasm_i32x4_dot_i16x8(v0hfh, v1hh)))),
                    wasm_f32x4_splat(GGML_FP16_TO_FP32(x0->d) * GGML_FP16_TO_FP32(y0->d))));
    }

    sumf = wasm_f32x4_extract_lane(sumv, 0) + wasm_f32x4_extract_lane(sumv, 1) +
           wasm_f32x4_extract_lane(sumv, 2) + wasm_f32x4_extract_lane(sumv, 3);
#endif

    for (; ib < nb; ++ib) {
        uint32_t qh;
        memcpy(&qh, x[ib].qh, sizeof(qh));

        int sumi0 = 0;
        int sumi1 = 0;

        for (int j = 0; j < qk/2; ++j) {
            const uint8_t xh_0 = ((qh & (1u << (j + 0 ))) >> (j + 0 )) << 4;
            const uint8_t xh_1 = ((qh & (1u << (j + 16))) >> (j + 12));

            const int32_t x0 = (int8_t)(((x[ib].qs[j] & 0x0F) | xh_0) - 16);
            const int32_t x1 = (int8_t)(((x[ib].qs[j] >>   4) | xh_1) - 16);

            sumi0 += (x0 * y[ib].qs[j]);
            sumi1 += (x1 * y[ib].qs[j + qk/2]);
        }

        int sumi = sumi0 + sumi1;
        sumf += (GGML_FP16_TO_FP32(x[ib].d)*GGML_FP16_TO_FP32(y[ib].d)) * sumi;
    }

    *s = sumf;
}

Here is the function that you need to convert:

void ggml_vec_dot_q8_0_q8_0(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
    const int qk = QK8_0;
    const int nb = n / qk;

    assert(n % qk == 0);
    assert(nrc == 1);
    UNUSED(nrc);
    UNUSED(bx);
    UNUSED(by);
    UNUSED(bs);

    const block_q8_0 * restrict x = vx;
    const block_q8_0 * restrict y = vy;

    int ib = 0;
    float sumf = 0;

#if defined(__ARM_NEON)
    float32x4_t sumv0 = vdupq_n_f32(0.0f);
    float32x4_t sumv1 = vdupq_n_f32(0.0f);

    for (; ib + 1 < nb; ib += 2) {
        const block_q8_0 * restrict x0 = &x[ib + 0];
        const block_q8_0 * restrict x1 = &x[ib + 1];
        const block_q8_0 * restrict y0 = &y[ib + 0];
        const block_q8_0 * restrict y1 = &y[ib + 1];

        const int8x16_t x0_0 = vld1q_s8(x0->qs);
        const int8x16_t x0_1 = vld1q_s8(x0->qs + 16);
        const int8x16_t x1_0 = vld1q_s8(x1->qs);
        const int8x16_t x1_1 = vld1q_s8(x1->qs + 16);

        // load y
        const int8x16_t y0_0 = vld1q_s8(y0->qs);
        const int8x16_t y0_1 = vld1q_s8(y0->qs + 16);
        const int8x16_t y1_0 = vld1q_s8(y1->qs);
        const int8x16_t y1_1 = vld1q_s8(y1->qs + 16);

        sumv0 = vmlaq_n_f32(sumv0, vcvtq_f32_s32(vaddq_s32(
                        ggml_vdotq_s32(vdupq_n_s32(0), x0_0, y0_0),
                        ggml_vdotq_s32(vdupq_n_s32(0), x0_1, y0_1))), GGML_FP16_TO_FP32(x0->d)*GGML_FP16_TO_FP32(y0->d));

        sumv1 = vmlaq_n_f32(sumv1, vcvtq_f32_s32(vaddq_s32(
                        ggml_vdotq_s32(vdupq_n_s32(0), x1_0, y1_0),
                        ggml_vdotq_s32(vdupq_n_s32(0), x1_1, y1_1))), GGML_FP16_TO_FP32(x1->d)*GGML_FP16_TO_FP32(y1->d));
    }

    sumf = vaddvq_f32(sumv0) + vaddvq_f32(sumv1);
#endif
    for (; ib < nb; ++ib) {
        int sumi = 0;

        for (int j = 0; j < qk; j++) {
            sumi += x[ib].qs[j]*y[ib].qs[j];
        }

        sumf += sumi*(GGML_FP16_TO_FP32(x[ib].d)*GGML_FP16_TO_FP32(y[ib].d));
    }

    *s = sumf;
}

You must start your code with #elif defined(__wasm_simd128__)

Raw

prompt2.md

Your task is to convert a given C code SIMD to WASM SIMD. Here is an example of another function:

void ggml_vec_dot_q4_K_q8_K(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
    assert(n % QK_K == 0);
    assert(nrc == 1);
    UNUSED(nrc);
    UNUSED(bx);
    UNUSED(by);
    UNUSED(bs);

    const block_q4_K * restrict x = vx;
    const block_q8_K * restrict y = vy;

    const int nb = n / QK_K;

    static const uint32_t kmask1 = 0x3f3f3f3f;
    static const uint32_t kmask2 = 0x0f0f0f0f;
    static const uint32_t kmask3 = 0x03030303;

    uint32_t utmp[4];

#ifdef __ARM_NEON
    const uint8x16_t m4b = vdupq_n_u8(0xf);
    const int32x4_t mzero = vdupq_n_s32(0);

    ggml_int8x16x2_t q4bytes;
    ggml_int8x16x2_t q8bytes;

    float sumf = 0;

    for (int i = 0; i < nb; ++i) {

        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);
        const float dmin = y[i].d * GGML_FP16_TO_FP32(x[i].dmin);

        const int16x8_t q8sums = vpaddq_s16(vld1q_s16(y[i].bsums), vld1q_s16(y[i].bsums + 8));

        memcpy(utmp, x[i].scales, 12);

        uint32x2_t mins8 = { 0 };
        mins8 = vset_lane_u32(utmp[1] & kmask1, mins8, 0);
        mins8 = vset_lane_u32(((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4), mins8, 1);

        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[0] &= kmask1;

        const int16x8_t mins = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(mins8)));
        const int32x4_t prod = vaddq_s32(vmull_s16(vget_low_s16 (q8sums), vget_low_s16 (mins)),
                                         vmull_s16(vget_high_s16(q8sums), vget_high_s16(mins)));
        sumf -= dmin * vaddvq_s32(prod);

        const uint8_t * scales = (const uint8_t *)utmp;

        const uint8_t * restrict q4 = x[i].qs;
        const int8_t  * restrict q8 = y[i].qs;

        int32_t sumi1 = 0;
        int32_t sumi2 = 0;

        for (int j = 0; j < QK_K/64; ++j) {
            const ggml_uint8x16x2_t q4bits = ggml_vld1q_u8_x2(q4); q4 += 32;

            q8bytes = ggml_vld1q_s8_x2(q8); q8 += 32;
            q4bytes.val[0] = vreinterpretq_s8_u8(vandq_u8  (q4bits.val[0], m4b));
            q4bytes.val[1] = vreinterpretq_s8_u8(vandq_u8  (q4bits.val[1], m4b));

            const int32x4_t p1 = ggml_vdotq_s32(ggml_vdotq_s32(mzero, q4bytes.val[0], q8bytes.val[0]), q4bytes.val[1], q8bytes.val[1]);
            sumi1 += vaddvq_s32(p1) * scales[2*j+0];

            q8bytes = ggml_vld1q_s8_x2(q8); q8 += 32;
            q4bytes.val[0] = vreinterpretq_s8_u8(vshrq_n_u8(q4bits.val[0], 4));
            q4bytes.val[1] = vreinterpretq_s8_u8(vshrq_n_u8(q4bits.val[1], 4));

            const int32x4_t p2 = ggml_vdotq_s32(ggml_vdotq_s32(mzero, q4bytes.val[0], q8bytes.val[0]), q4bytes.val[1], q8bytes.val[1]);

            sumi2 += vaddvq_s32(p2) * scales[2*j+1];
        }

        sumf += d * (sumi1 + sumi2);

    }

    *s = sumf;

#elif defined(__wasm_simd128__)
    // WASM SIMD128 implementation
    const uint8_t * scales = (const uint8_t*)&utmp[0];
    float sumf = 0;

    for (int i = 0; i < nb; ++i) {
        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);
        const float dmin = y[i].d * GGML_FP16_TO_FP32(x[i].dmin); // Corrected sign

        const uint8_t * restrict q4 = x[i].qs;
        const int8_t  * restrict q8 = y[i].qs;

        // Process scales and mins
        memcpy(utmp, x[i].scales, 12);
        utmp[3] = ((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4);
        const uint32_t uaux = utmp[1] & kmask1;
        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[2] = uaux;
        utmp[0] &= kmask1;

        // Sum mins * q8sums
        int32_t sumi = 0;
        const int16_t * restrict q8sums = y[i].bsums;
        const uint8_t * m = (const uint8_t *)&utmp[2];
        for (int j = 0; j < 16; j += 2) {
            sumi += (q8sums[j] + q8sums[j+1]) * m[j/2];
        }
        sumf -= dmin * sumi;

        int32_t sumi1 = 0;
        int32_t sumi2 = 0;

        for (int j = 0; j < QK_K/64; ++j) {
            // Load 64 4-bit weights (32 bytes)
            const v128_t q4x0 = wasm_v128_load(q4);
            const v128_t q4x1 = wasm_v128_load(q4 + 16);
            q4 += 32;

            // Split into low/high nibbles
            const v128_t q4l0 = wasm_v128_and(q4x0, wasm_i8x16_splat(0x0F));
            const v128_t q4h0 = wasm_u8x16_shr(q4x0, 4);
            const v128_t q4l1 = wasm_v128_and(q4x1, wasm_i8x16_splat(0x0F));
            const v128_t q4h1 = wasm_u8x16_shr(q4x1, 4);

            // Load 64 8-bit values (64 bytes)
            const v128_t q8x0 = wasm_v128_load(q8);
            const v128_t q8x1 = wasm_v128_load(q8 + 16);
            const v128_t q8x2 = wasm_v128_load(q8 + 32);
            const v128_t q8x3 = wasm_v128_load(q8 + 48);
            q8 += 64;

            // Low nibble products
            v128_t vacc1 = wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4l0),
                wasm_i16x8_extend_low_i8x16(q8x0)
            );
            vacc1 = wasm_i32x4_add(vacc1, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4l0),
                wasm_i16x8_extend_high_i8x16(q8x0)
            ));
            vacc1 = wasm_i32x4_add(vacc1, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4l1),
                wasm_i16x8_extend_low_i8x16(q8x1)
            ));
            vacc1 = wasm_i32x4_add(vacc1, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4l1),
                wasm_i16x8_extend_high_i8x16(q8x1)
            ));

            // High nibble products
            v128_t vacc2 = wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4h0),
                wasm_i16x8_extend_low_i8x16(q8x2)
            );
            vacc2 = wasm_i32x4_add(vacc2, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4h0),
                wasm_i16x8_extend_high_i8x16(q8x2)
            ));
            vacc2 = wasm_i32x4_add(vacc2, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4h1),
                wasm_i16x8_extend_low_i8x16(q8x3)
            ));
            vacc2 = wasm_i32x4_add(vacc2, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4h1),
                wasm_i16x8_extend_high_i8x16(q8x3)
            ));

            // Accumulate scaled results
            int32_t vacc1_sum = wasm_i32x4_extract_lane(vacc1, 0) + wasm_i32x4_extract_lane(vacc1, 1) +
                                wasm_i32x4_extract_lane(vacc1, 2) + wasm_i32x4_extract_lane(vacc1, 3);
            sumi1 += vacc1_sum * scales[2*j];

            int32_t vacc2_sum = wasm_i32x4_extract_lane(vacc2, 0) + wasm_i32x4_extract_lane(vacc2, 1) +
                                wasm_i32x4_extract_lane(vacc2, 2) + wasm_i32x4_extract_lane(vacc2, 3);
            sumi2 += vacc2_sum * scales[2*j+1];
        }

        sumf += d * (sumi1 + sumi2);
    }

    *s = sumf;

#elif defined __AVX__

    const __m128i m4 = _mm_set1_epi8(0xF);
    const __m128i m2 = _mm_set1_epi8(0x2);

    __m256 acc = _mm256_setzero_ps();
    __m128 acc_m = _mm_setzero_ps();

   for (int i = 0; i < nb; ++i) {

        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);
        const float dmin = -y[i].d * GGML_FP16_TO_FP32(x[i].dmin);

        const uint8_t * restrict q4 = x[i].qs;
        const int8_t  * restrict q8 = y[i].qs;

        memcpy(utmp, x[i].scales, 12);
        utmp[3] = ((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4);
        const uint32_t uaux = utmp[1] & kmask1;
        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[2] = uaux;
        utmp[0] &= kmask1;

        const __m128i utmps = _mm_set_epi32(utmp[3], utmp[2], utmp[1], utmp[0]);
        const __m128i scales = _mm_cvtepu8_epi16(utmps);
        const __m128i mins = _mm_cvtepu8_epi16(_mm_unpackhi_epi64(utmps, utmps));

        const __m128i q8sums_0 = _mm_loadu_si128((const __m128i*)&y[i].bsums[0]);
        const __m128i q8sums_1 = _mm_loadu_si128((const __m128i*)&y[i].bsums[8]);
        const __m128i q8s = _mm_hadd_epi16(q8sums_0, q8sums_1);
        const __m128i prod = _mm_madd_epi16(mins, q8s);
        acc_m = _mm_add_ps(_mm_mul_ps(_mm_set1_ps(dmin), _mm_cvtepi32_ps(prod)), acc_m);

        __m128i sumi_0 = _mm_setzero_si128();
        __m128i sumi_1 = _mm_setzero_si128();

        __m128i shuffle = _mm_set1_epi16(0x0100);
        for (int j = 0; j < QK_K/64; ++j) {

            const __m128i scale_l = _mm_shuffle_epi8(scales, shuffle);
            shuffle = _mm_add_epi16(shuffle, m2);
            const __m128i scale_h = _mm_shuffle_epi8(scales, shuffle);
            shuffle = _mm_add_epi16(shuffle, m2);

            __m128i q4bits = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4l_0 = _mm_and_si128(q4bits, m4);
            const __m128i q4h_0 = _mm_and_si128(_mm_srli_epi16(q4bits, 4), m4);
            q4bits = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4l_1 = _mm_and_si128(q4bits, m4);
            const __m128i q4h_1 = _mm_and_si128(_mm_srli_epi16(q4bits, 4), m4);

            const __m128i q8l_0 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            __m128i p16l = _mm_maddubs_epi16(q4l_0, q8l_0);
            p16l = _mm_madd_epi16(scale_l, p16l);
            sumi_0 = _mm_add_epi32(sumi_0, p16l);
            const __m128i q8l_1 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            p16l = _mm_maddubs_epi16(q4l_1, q8l_1);
            p16l = _mm_madd_epi16(scale_l, p16l);
            sumi_1 = _mm_add_epi32(sumi_1, p16l);

            const __m128i q8h_0 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            __m128i p16h = _mm_maddubs_epi16(q4h_0, q8h_0);
            p16h = _mm_madd_epi16(scale_h, p16h);
            sumi_0 = _mm_add_epi32(sumi_0, p16h);
            const __m128i q8h_1 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            p16h = _mm_maddubs_epi16(q4h_1, q8h_1);
            p16h = _mm_madd_epi16(scale_h, p16h);
            sumi_1 = _mm_add_epi32(sumi_1, p16h);

        }

        __m256 vd = _mm256_set1_ps(d);
        __m256i sumi = MM256_SET_M128I(sumi_1, sumi_0);
        acc = _mm256_add_ps(_mm256_mul_ps(vd, _mm256_cvtepi32_ps(sumi)), acc);

    }

    acc_m = _mm_add_ps(acc_m, _mm_movehl_ps(acc_m, acc_m));
    acc_m = _mm_add_ss(acc_m, _mm_movehdup_ps(acc_m));

    *s = hsum_float_8(acc) + _mm_cvtss_f32(acc_m);

#else

    const uint8_t * scales = (const uint8_t*)&utmp[0];
    const uint8_t * mins   = (const uint8_t*)&utmp[2];

    int8_t  aux8[QK_K];
    int16_t aux16[8];
    float   sums [8];
    int32_t aux32[8];
    memset(sums, 0, 8*sizeof(float));

    float sumf = 0;
    for (int i = 0; i < nb; ++i) {
        const uint8_t * restrict q4 = x[i].qs;
        const  int8_t * restrict q8 = y[i].qs;
        memset(aux32, 0, 8*sizeof(int32_t));
        int8_t * restrict a = aux8;
        for (int j = 0; j < QK_K/64; ++j) {
            for (int l = 0; l < 32; ++l) a[l] = (int8_t)(q4[l] & 0xF);
            a += 32;
            for (int l = 0; l < 32; ++l) a[l] = (int8_t)(q4[l]  >> 4);
            a += 32; q4 += 32;
        }
        memcpy(utmp, x[i].scales, 12);
        utmp[3] = ((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4);
        const uint32_t uaux = utmp[1] & kmask1;
        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[2] = uaux;
        utmp[0] &= kmask1;

        int sumi = 0;
        for (int j = 0; j < QK_K/16; ++j) sumi += y[i].bsums[j] * mins[j/2];
        a = aux8;
        int is = 0;
        for (int j = 0; j < QK_K/32; ++j) {
            int32_t scale = scales[is++];
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
        }
        const float d = GGML_FP16_TO_FP32(x[i].d) * y[i].d;
        for (int l = 0; l < 8; ++l) sums[l] += d * aux32[l];
        const float dmin = GGML_FP16_TO_FP32(x[i].dmin) * y[i].d;
        sumf -= dmin * sumi;
    }
    for (int l = 0; l < 8; ++l) sumf += sums[l];
    *s = sumf;
#endif
}

Here is a function. You need to convert it to WASM SIMD.

void ggml_vec_dot_q6_K_q8_K(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
    assert(n % QK_K == 0);
    assert(nrc == 1);
    UNUSED(nrc);
    UNUSED(bx);
    UNUSED(by);
    UNUSED(bs);

    const block_q6_K * restrict x = vx;
    const block_q8_K * restrict y = vy;

    const int nb = n / QK_K;

#ifdef __ARM_NEON
    float sum = 0;

    const uint8x16_t m4b = vdupq_n_u8(0xF);
    const int32x4_t  vzero = vdupq_n_s32(0);
    //const int8x16_t  m32s = vdupq_n_s8(32);

    const uint8x16_t mone = vdupq_n_u8(3);

    ggml_int8x16x4_t q6bytes;
    ggml_uint8x16x4_t q6h;

    for (int i = 0; i < nb; ++i) {

        const float d_all = GGML_FP16_TO_FP32(x[i].d);

        const uint8_t * restrict q6 = x[i].ql;
        const uint8_t * restrict qh = x[i].qh;
        const int8_t  * restrict q8 = y[i].qs;

        const int8_t * restrict scale = x[i].scales;

        const ggml_int16x8x2_t q8sums = ggml_vld1q_s16_x2(y[i].bsums);
        const int8x16_t scales = vld1q_s8(scale);
        const ggml_int16x8x2_t q6scales = {{vmovl_s8(vget_low_s8(scales)), vmovl_s8(vget_high_s8(scales))}};

        const int32x4_t prod = vaddq_s32(vaddq_s32(vmull_s16(vget_low_s16 (q8sums.val[0]), vget_low_s16 (q6scales.val[0])),
                                                   vmull_s16(vget_high_s16(q8sums.val[0]), vget_high_s16(q6scales.val[0]))),
                                         vaddq_s32(vmull_s16(vget_low_s16 (q8sums.val[1]), vget_low_s16 (q6scales.val[1])),
                                                   vmull_s16(vget_high_s16(q8sums.val[1]), vget_high_s16(q6scales.val[1]))));
        int32_t isum_mins = vaddvq_s32(prod);

        int32_t isum = 0;

        for (int j = 0; j < QK_K/128; ++j) {

            ggml_uint8x16x2_t qhbits = ggml_vld1q_u8_x2(qh); qh += 32;
            ggml_uint8x16x4_t q6bits = ggml_vld1q_u8_x4(q6); q6 += 64;
            ggml_int8x16x4_t q8bytes = ggml_vld1q_s8_x4(q8); q8 += 64;

            q6h.val[0] = vshlq_n_u8(vandq_u8(mone, qhbits.val[0]), 4);
            q6h.val[1] = vshlq_n_u8(vandq_u8(mone, qhbits.val[1]), 4);
            uint8x16_t shifted = vshrq_n_u8(qhbits.val[0], 2);
            q6h.val[2] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[1], 2);
            q6h.val[3] = vshlq_n_u8(vandq_u8(mone, shifted), 4);

            q6bytes.val[0] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[0], m4b), q6h.val[0]));
            q6bytes.val[1] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[1], m4b), q6h.val[1]));
            q6bytes.val[2] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[2], m4b), q6h.val[2]));
            q6bytes.val[3] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[3], m4b), q6h.val[3]));

            isum += vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[0], q8bytes.val[0])) * scale[0] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[1], q8bytes.val[1])) * scale[1] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[2], q8bytes.val[2])) * scale[2] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[3], q8bytes.val[3])) * scale[3];

            scale += 4;

            q8bytes = ggml_vld1q_s8_x4(q8); q8 += 64;

            shifted = vshrq_n_u8(qhbits.val[0], 4);
            q6h.val[0] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[1], 4);
            q6h.val[1] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[0], 6);
            q6h.val[2] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[1], 6);
            q6h.val[3] = vshlq_n_u8(vandq_u8(mone, shifted), 4);

            q6bytes.val[0] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[0], 4), q6h.val[0]));
            q6bytes.val[1] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[1], 4), q6h.val[1]));
            q6bytes.val[2] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[2], 4), q6h.val[2]));
            q6bytes.val[3] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[3], 4), q6h.val[3]));

            isum += vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[0], q8bytes.val[0])) * scale[0] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[1], q8bytes.val[1])) * scale[1] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[2], q8bytes.val[2])) * scale[2] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[3], q8bytes.val[3])) * scale[3];
            scale += 4;
        }
        //sum += isum * d_all * y[i].d;
        sum += d_all * y[i].d * (isum - 32 * isum_mins);

    }
    *s = sum;

#elif defined __AVX__

    const __m128i m3 = _mm_set1_epi8(3);
    const __m128i m15 = _mm_set1_epi8(15);

    __m256 acc = _mm256_setzero_ps();

    for (int i = 0; i < nb; ++i) {

        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);

        const uint8_t * restrict q4 = x[i].ql;
        const uint8_t * restrict qh = x[i].qh;
        const int8_t  * restrict q8 = y[i].qs;

        // handle the q6_k -32 offset separately using bsums
        const __m128i q8sums_0 = _mm_loadu_si128((const __m128i*)y[i].bsums);
        const __m128i q8sums_1 = _mm_loadu_si128((const __m128i*)y[i].bsums + 1);
        const __m128i scales = _mm_loadu_si128((const __m128i*)x[i].scales);
        const __m128i scales_16_0 = _mm_cvtepi8_epi16(scales);
        const __m128i scales_16_1 = _mm_cvtepi8_epi16(_mm_bsrli_si128(scales, 8));
        const __m128i q8sclsub_0 = _mm_slli_epi32(_mm_madd_epi16(q8sums_0, scales_16_0), 5);
        const __m128i q8sclsub_1 = _mm_slli_epi32(_mm_madd_epi16(q8sums_1, scales_16_1), 5);

        __m128i sumi_0 = _mm_setzero_si128();
        __m128i sumi_1 = _mm_setzero_si128();

        int is = 0;

        for (int j = 0; j < QK_K/128; ++j) {

            const __m128i q4bitsH_0 = _mm_loadu_si128((const __m128i*)qh); qh += 16;
            const __m128i q4bitsH_1 = _mm_loadu_si128((const __m128i*)qh); qh += 16;

            const __m128i q4h_0 = _mm_slli_epi16(_mm_and_si128(q4bitsH_0, m3), 4);
            const __m128i q4h_1 = _mm_slli_epi16(_mm_and_si128(q4bitsH_1, m3), 4);
            const __m128i q4h_2 = _mm_slli_epi16(_mm_and_si128(q4bitsH_0, _mm_set1_epi8(12)), 2);
            const __m128i q4h_3 = _mm_slli_epi16(_mm_and_si128(q4bitsH_1, _mm_set1_epi8(12)), 2);
            const __m128i q4h_4 = _mm_and_si128(q4bitsH_0, _mm_set1_epi8(48));
            const __m128i q4h_5 = _mm_and_si128(q4bitsH_1, _mm_set1_epi8(48));
            const __m128i q4h_6 = _mm_srli_epi16(_mm_and_si128(q4bitsH_0, _mm_set1_epi8(-64)), 2);
            const __m128i q4h_7 = _mm_srli_epi16(_mm_and_si128(q4bitsH_1, _mm_set1_epi8(-64)), 2);

            const __m128i q4bits1_0 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4bits1_1 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4bits2_0 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4bits2_1 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;

            const __m128i q4_0 = _mm_or_si128(_mm_and_si128(q4bits1_0, m15), q4h_0);
            const __m128i q4_1 = _mm_or_si128(_mm_and_si128(q4bits1_1, m15), q4h_1);
            const __m128i q4_2 = _mm_or_si128(_mm_and_si128(q4bits2_0, m15), q4h_2);
            const __m128i q4_3 = _mm_or_si128(_mm_and_si128(q4bits2_1, m15), q4h_3);
            const __m128i q4_4 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits1_0, 4), m15), q4h_4);
            const __m128i q4_5 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits1_1, 4), m15), q4h_5);
            const __m128i q4_6 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits2_0, 4), m15), q4h_6);
            const __m128i q4_7 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits2_1, 4), m15), q4h_7);

            const __m128i q8_0 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_1 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_2 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_3 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_4 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_5 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_6 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_7 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;

            __m128i p16_0 = _mm_maddubs_epi16(q4_0, q8_0);
            __m128i p16_1 = _mm_maddubs_epi16(q4_1, q8_1);
            __m128i p16_2 = _mm_maddubs_epi16(q4_2, q8_2);
            __m128i p16_3 = _mm_maddubs_epi16(q4_3, q8_3);
            __m128i p16_4 = _mm_maddubs_epi16(q4_4, q8_4);
            __m128i p16_5 = _mm_maddubs_epi16(q4_5, q8_5);
            __m128i p16_6 = _mm_maddubs_epi16(q4_6, q8_6);
            __m128i p16_7 = _mm_maddubs_epi16(q4_7, q8_7);

            const __m128i scale_0 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 0));
            const __m128i scale_1 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 1));
            const __m128i scale_2 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 2));
            const __m128i scale_3 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 3));
            is += 4;

            p16_0 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_0), p16_0);
            p16_1 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_0, 8)), p16_1);
            p16_2 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_1), p16_2);
            p16_3 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_1, 8)), p16_3);
            p16_4 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_2), p16_4);
            p16_5 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_2, 8)), p16_5);
            p16_6 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_3), p16_6);
            p16_7 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_3, 8)), p16_7);

            sumi_0 = _mm_add_epi32(sumi_0, _mm_add_epi32(p16_0, p16_2));
            sumi_1 = _mm_add_epi32(sumi_1, _mm_add_epi32(p16_1, p16_3));
            sumi_0 = _mm_add_epi32(sumi_0, _mm_add_epi32(p16_4, p16_6));
            sumi_1 = _mm_add_epi32(sumi_1, _mm_add_epi32(p16_5, p16_7));

        }

        sumi_0 = _mm_sub_epi32(sumi_0, q8sclsub_0);
        sumi_1 = _mm_sub_epi32(sumi_1, q8sclsub_1);
        const __m256i sumi = MM256_SET_M128I(sumi_1, sumi_0);
        acc = _mm256_add_ps(_mm256_mul_ps(_mm256_set1_ps(d), _mm256_cvtepi32_ps(sumi)), acc);
    }

    *s = hsum_float_8(acc);

#else

    int8_t  aux8[QK_K];
    int16_t aux16[8];
    float   sums [8];
    int32_t aux32[8];
    memset(sums, 0, 8*sizeof(float));

    float sumf = 0;
    for (int i = 0; i < nb; ++i) {
        const uint8_t * restrict q4 = x[i].ql;
        const uint8_t * restrict qh = x[i].qh;
        const  int8_t * restrict q8 = y[i].qs;
        memset(aux32, 0, 8*sizeof(int32_t));
        int8_t * restrict a = aux8;
        for (int j = 0; j < QK_K; j += 128) {
            for (int l = 0; l < 32; ++l) {
                a[l +  0] = (int8_t)((q4[l +  0] & 0xF) | (((qh[l] >> 0) & 3) << 4)) - 32;
                a[l + 32] = (int8_t)((q4[l + 32] & 0xF) | (((qh[l] >> 2) & 3) << 4)) - 32;
                a[l + 64] = (int8_t)((q4[l +  0] >>  4) | (((qh[l] >> 4) & 3) << 4)) - 32;
                a[l + 96] = (int8_t)((q4[l + 32] >>  4) | (((qh[l] >> 6) & 3) << 4)) - 32;
            }
            a  += 128;
            q4 += 64;
            qh += 32;
        }
        a = aux8;
        int is = 0;
        for (int j = 0; j < QK_K/16; ++j) {
            int scale = x[i].scales[is++];
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
        }
        const float d = GGML_FP16_TO_FP32(x[i].d) * y[i].d;
        for (int l = 0; l < 8; ++l) sums[l] += d * aux32[l];
    }
    for (int l = 0; l < 8; ++l) sumf += sums[l];
    *s = sumf;
#endif
}

You must start your code with #elif defined(__wasm_simd128__)

To think about it, you need to take into account both the refenrence code from ARM NEON and AVX implementation.

Raw

prompt3.md

Here is a function in C, you have to convert it to WASM SIMD 128:

You must start your code with #elif defined(__wasm_simd128__)

To think about it, you need to take into account both the refenrence code from ARM NEON and AVX implementation.

Please note that this is YOUR last attempt. It compiles, but give inaccurate result. Improve from that.

You must start your code with #elif defined(__wasm_simd128__)

To think about it, you need to take into account both the refenrence code from ARM NEON, riscv_v_intrinsic and other implementation that you can see on the code. Make sure the output value is as accurate as possible.

Raw

prompt_from_scratch.md

Here is a function in C, you have to convert it to WASM SIMD 128.

This function is prone to produce inaccuracy result, it is very sensitive. Only optimize part that you are absolutely sure.

Think carefully about it. Hint, focus more on the loop with aux16, aux32

void ggml_vec_dot_q6_K_q8_K(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
    assert(n % QK_K == 0);
    assert(nrc == 1);
    UNUSED(nrc);
    UNUSED(bx);
    UNUSED(by);
    UNUSED(bs);

    const block_q6_K * restrict x = vx;
    const block_q8_K * restrict y = vy;

    const int nb = n / QK_K;

    int8_t  aux8[QK_K];
    int16_t aux16[8];
    float   sums [8];
    int32_t aux32[8];
    memset(sums, 0, 8*sizeof(float));

    float sumf = 0;
    for (int i = 0; i < nb; ++i) {
        const uint8_t * restrict q4 = x[i].ql;
        const uint8_t * restrict qh = x[i].qh;
        const  int8_t * restrict q8 = y[i].qs;
        memset(aux32, 0, 8*sizeof(int32_t));
        int8_t * restrict a = aux8;
        for (int j = 0; j < QK_K; j += 128) {
            for (int l = 0; l < 32; ++l) {
                a[l +  0] = (int8_t)((q4[l +  0] & 0xF) | (((qh[l] >> 0) & 3) << 4)) - 32;
                a[l + 32] = (int8_t)((q4[l + 32] & 0xF) | (((qh[l] >> 2) & 3) << 4)) - 32;
                a[l + 64] = (int8_t)((q4[l +  0] >>  4) | (((qh[l] >> 4) & 3) << 4)) - 32;
                a[l + 96] = (int8_t)((q4[l + 32] >>  4) | (((qh[l] >> 6) & 3) << 4)) - 32;
            }
            a  += 128;
            q4 += 64;
            qh += 32;
        }
        a = aux8;
        int is = 0;
        for (int j = 0; j < QK_K/16; ++j) {
            int scale = x[i].scales[is++];
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
        }
        const float d = GGML_FP16_TO_FP32(x[i].d) * y[i].d;
        for (int l = 0; l < 8; ++l) sums[l] += d * aux32[l];
    }
    for (int l = 0; l < 8; ++l) sumf += sums[l];
    *s = sumf;
}

Raw

prompt_hard.md

NOTE: This task (q6_K_q8_K) is HARD. The prompt below always produces failed result

Your task is to convert a given C code SIMD to WASM SIMD. Here is an example of another function:

void ggml_vec_dot_q4_K_q8_K(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
    assert(n % QK_K == 0);
    assert(nrc == 1);
    UNUSED(nrc);
    UNUSED(bx);
    UNUSED(by);
    UNUSED(bs);

    const block_q4_K * restrict x = vx;
    const block_q8_K * restrict y = vy;

    const int nb = n / QK_K;

    static const uint32_t kmask1 = 0x3f3f3f3f;
    static const uint32_t kmask2 = 0x0f0f0f0f;
    static const uint32_t kmask3 = 0x03030303;

    uint32_t utmp[4];

#ifdef __ARM_NEON
    const uint8x16_t m4b = vdupq_n_u8(0xf);
    const int32x4_t mzero = vdupq_n_s32(0);

    ggml_int8x16x2_t q4bytes;
    ggml_int8x16x2_t q8bytes;

    float sumf = 0;

    for (int i = 0; i < nb; ++i) {

        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);
        const float dmin = y[i].d * GGML_FP16_TO_FP32(x[i].dmin);

        const int16x8_t q8sums = vpaddq_s16(vld1q_s16(y[i].bsums), vld1q_s16(y[i].bsums + 8));

        memcpy(utmp, x[i].scales, 12);

        uint32x2_t mins8 = { 0 };
        mins8 = vset_lane_u32(utmp[1] & kmask1, mins8, 0);
        mins8 = vset_lane_u32(((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4), mins8, 1);

        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[0] &= kmask1;

        const int16x8_t mins = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(mins8)));
        const int32x4_t prod = vaddq_s32(vmull_s16(vget_low_s16 (q8sums), vget_low_s16 (mins)),
                                         vmull_s16(vget_high_s16(q8sums), vget_high_s16(mins)));
        sumf -= dmin * vaddvq_s32(prod);

        const uint8_t * scales = (const uint8_t *)utmp;

        const uint8_t * restrict q4 = x[i].qs;
        const int8_t  * restrict q8 = y[i].qs;

        int32_t sumi1 = 0;
        int32_t sumi2 = 0;

        for (int j = 0; j < QK_K/64; ++j) {
            const ggml_uint8x16x2_t q4bits = ggml_vld1q_u8_x2(q4); q4 += 32;

            q8bytes = ggml_vld1q_s8_x2(q8); q8 += 32;
            q4bytes.val[0] = vreinterpretq_s8_u8(vandq_u8  (q4bits.val[0], m4b));
            q4bytes.val[1] = vreinterpretq_s8_u8(vandq_u8  (q4bits.val[1], m4b));

            const int32x4_t p1 = ggml_vdotq_s32(ggml_vdotq_s32(mzero, q4bytes.val[0], q8bytes.val[0]), q4bytes.val[1], q8bytes.val[1]);
            sumi1 += vaddvq_s32(p1) * scales[2*j+0];

            q8bytes = ggml_vld1q_s8_x2(q8); q8 += 32;
            q4bytes.val[0] = vreinterpretq_s8_u8(vshrq_n_u8(q4bits.val[0], 4));
            q4bytes.val[1] = vreinterpretq_s8_u8(vshrq_n_u8(q4bits.val[1], 4));

            const int32x4_t p2 = ggml_vdotq_s32(ggml_vdotq_s32(mzero, q4bytes.val[0], q8bytes.val[0]), q4bytes.val[1], q8bytes.val[1]);

            sumi2 += vaddvq_s32(p2) * scales[2*j+1];
        }

        sumf += d * (sumi1 + sumi2);

    }

    *s = sumf;

#elif defined(__wasm_simd128__)
    // WASM SIMD128 implementation
    const uint8_t * scales = (const uint8_t*)&utmp[0];
    float sumf = 0;

    for (int i = 0; i < nb; ++i) {
        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);
        const float dmin = y[i].d * GGML_FP16_TO_FP32(x[i].dmin); // Corrected sign

        const uint8_t * restrict q4 = x[i].qs;
        const int8_t  * restrict q8 = y[i].qs;

        // Process scales and mins
        memcpy(utmp, x[i].scales, 12);
        utmp[3] = ((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4);
        const uint32_t uaux = utmp[1] & kmask1;
        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[2] = uaux;
        utmp[0] &= kmask1;

        // Sum mins * q8sums
        int32_t sumi = 0;
        const int16_t * restrict q8sums = y[i].bsums;
        const uint8_t * m = (const uint8_t *)&utmp[2];
        for (int j = 0; j < 16; j += 2) {
            sumi += (q8sums[j] + q8sums[j+1]) * m[j/2];
        }
        sumf -= dmin * sumi;

        int32_t sumi1 = 0;
        int32_t sumi2 = 0;

        for (int j = 0; j < QK_K/64; ++j) {
            // Load 64 4-bit weights (32 bytes)
            const v128_t q4x0 = wasm_v128_load(q4);
            const v128_t q4x1 = wasm_v128_load(q4 + 16);
            q4 += 32;

            // Split into low/high nibbles
            const v128_t q4l0 = wasm_v128_and(q4x0, wasm_i8x16_splat(0x0F));
            const v128_t q4h0 = wasm_u8x16_shr(q4x0, 4);
            const v128_t q4l1 = wasm_v128_and(q4x1, wasm_i8x16_splat(0x0F));
            const v128_t q4h1 = wasm_u8x16_shr(q4x1, 4);

            // Load 64 8-bit values (64 bytes)
            const v128_t q8x0 = wasm_v128_load(q8);
            const v128_t q8x1 = wasm_v128_load(q8 + 16);
            const v128_t q8x2 = wasm_v128_load(q8 + 32);
            const v128_t q8x3 = wasm_v128_load(q8 + 48);
            q8 += 64;

            // Low nibble products
            v128_t vacc1 = wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4l0),
                wasm_i16x8_extend_low_i8x16(q8x0)
            );
            vacc1 = wasm_i32x4_add(vacc1, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4l0),
                wasm_i16x8_extend_high_i8x16(q8x0)
            ));
            vacc1 = wasm_i32x4_add(vacc1, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4l1),
                wasm_i16x8_extend_low_i8x16(q8x1)
            ));
            vacc1 = wasm_i32x4_add(vacc1, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4l1),
                wasm_i16x8_extend_high_i8x16(q8x1)
            ));

            // High nibble products
            v128_t vacc2 = wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4h0),
                wasm_i16x8_extend_low_i8x16(q8x2)
            );
            vacc2 = wasm_i32x4_add(vacc2, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4h0),
                wasm_i16x8_extend_high_i8x16(q8x2)
            ));
            vacc2 = wasm_i32x4_add(vacc2, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_low_i8x16(q4h1),
                wasm_i16x8_extend_low_i8x16(q8x3)
            ));
            vacc2 = wasm_i32x4_add(vacc2, wasm_i32x4_dot_i16x8(
                wasm_i16x8_extend_high_i8x16(q4h1),
                wasm_i16x8_extend_high_i8x16(q8x3)
            ));

            // Accumulate scaled results
            int32_t vacc1_sum = wasm_i32x4_extract_lane(vacc1, 0) + wasm_i32x4_extract_lane(vacc1, 1) +
                                wasm_i32x4_extract_lane(vacc1, 2) + wasm_i32x4_extract_lane(vacc1, 3);
            sumi1 += vacc1_sum * scales[2*j];

            int32_t vacc2_sum = wasm_i32x4_extract_lane(vacc2, 0) + wasm_i32x4_extract_lane(vacc2, 1) +
                                wasm_i32x4_extract_lane(vacc2, 2) + wasm_i32x4_extract_lane(vacc2, 3);
            sumi2 += vacc2_sum * scales[2*j+1];
        }

        sumf += d * (sumi1 + sumi2);
    }

    *s = sumf;

#elif defined __AVX__

    const __m128i m4 = _mm_set1_epi8(0xF);
    const __m128i m2 = _mm_set1_epi8(0x2);

    __m256 acc = _mm256_setzero_ps();
    __m128 acc_m = _mm_setzero_ps();

   for (int i = 0; i < nb; ++i) {

        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);
        const float dmin = -y[i].d * GGML_FP16_TO_FP32(x[i].dmin);

        const uint8_t * restrict q4 = x[i].qs;
        const int8_t  * restrict q8 = y[i].qs;

        memcpy(utmp, x[i].scales, 12);
        utmp[3] = ((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4);
        const uint32_t uaux = utmp[1] & kmask1;
        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[2] = uaux;
        utmp[0] &= kmask1;

        const __m128i utmps = _mm_set_epi32(utmp[3], utmp[2], utmp[1], utmp[0]);
        const __m128i scales = _mm_cvtepu8_epi16(utmps);
        const __m128i mins = _mm_cvtepu8_epi16(_mm_unpackhi_epi64(utmps, utmps));

        const __m128i q8sums_0 = _mm_loadu_si128((const __m128i*)&y[i].bsums[0]);
        const __m128i q8sums_1 = _mm_loadu_si128((const __m128i*)&y[i].bsums[8]);
        const __m128i q8s = _mm_hadd_epi16(q8sums_0, q8sums_1);
        const __m128i prod = _mm_madd_epi16(mins, q8s);
        acc_m = _mm_add_ps(_mm_mul_ps(_mm_set1_ps(dmin), _mm_cvtepi32_ps(prod)), acc_m);

        __m128i sumi_0 = _mm_setzero_si128();
        __m128i sumi_1 = _mm_setzero_si128();

        __m128i shuffle = _mm_set1_epi16(0x0100);
        for (int j = 0; j < QK_K/64; ++j) {

            const __m128i scale_l = _mm_shuffle_epi8(scales, shuffle);
            shuffle = _mm_add_epi16(shuffle, m2);
            const __m128i scale_h = _mm_shuffle_epi8(scales, shuffle);
            shuffle = _mm_add_epi16(shuffle, m2);

            __m128i q4bits = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4l_0 = _mm_and_si128(q4bits, m4);
            const __m128i q4h_0 = _mm_and_si128(_mm_srli_epi16(q4bits, 4), m4);
            q4bits = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4l_1 = _mm_and_si128(q4bits, m4);
            const __m128i q4h_1 = _mm_and_si128(_mm_srli_epi16(q4bits, 4), m4);

            const __m128i q8l_0 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            __m128i p16l = _mm_maddubs_epi16(q4l_0, q8l_0);
            p16l = _mm_madd_epi16(scale_l, p16l);
            sumi_0 = _mm_add_epi32(sumi_0, p16l);
            const __m128i q8l_1 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            p16l = _mm_maddubs_epi16(q4l_1, q8l_1);
            p16l = _mm_madd_epi16(scale_l, p16l);
            sumi_1 = _mm_add_epi32(sumi_1, p16l);

            const __m128i q8h_0 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            __m128i p16h = _mm_maddubs_epi16(q4h_0, q8h_0);
            p16h = _mm_madd_epi16(scale_h, p16h);
            sumi_0 = _mm_add_epi32(sumi_0, p16h);
            const __m128i q8h_1 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            p16h = _mm_maddubs_epi16(q4h_1, q8h_1);
            p16h = _mm_madd_epi16(scale_h, p16h);
            sumi_1 = _mm_add_epi32(sumi_1, p16h);

        }

        __m256 vd = _mm256_set1_ps(d);
        __m256i sumi = MM256_SET_M128I(sumi_1, sumi_0);
        acc = _mm256_add_ps(_mm256_mul_ps(vd, _mm256_cvtepi32_ps(sumi)), acc);

    }

    acc_m = _mm_add_ps(acc_m, _mm_movehl_ps(acc_m, acc_m));
    acc_m = _mm_add_ss(acc_m, _mm_movehdup_ps(acc_m));

    *s = hsum_float_8(acc) + _mm_cvtss_f32(acc_m);

#else

    const uint8_t * scales = (const uint8_t*)&utmp[0];
    const uint8_t * mins   = (const uint8_t*)&utmp[2];

    int8_t  aux8[QK_K];
    int16_t aux16[8];
    float   sums [8];
    int32_t aux32[8];
    memset(sums, 0, 8*sizeof(float));

    float sumf = 0;
    for (int i = 0; i < nb; ++i) {
        const uint8_t * restrict q4 = x[i].qs;
        const  int8_t * restrict q8 = y[i].qs;
        memset(aux32, 0, 8*sizeof(int32_t));
        int8_t * restrict a = aux8;
        for (int j = 0; j < QK_K/64; ++j) {
            for (int l = 0; l < 32; ++l) a[l] = (int8_t)(q4[l] & 0xF);
            a += 32;
            for (int l = 0; l < 32; ++l) a[l] = (int8_t)(q4[l]  >> 4);
            a += 32; q4 += 32;
        }
        memcpy(utmp, x[i].scales, 12);
        utmp[3] = ((utmp[2] >> 4) & kmask2) | (((utmp[1] >> 6) & kmask3) << 4);
        const uint32_t uaux = utmp[1] & kmask1;
        utmp[1] = (utmp[2] & kmask2) | (((utmp[0] >> 6) & kmask3) << 4);
        utmp[2] = uaux;
        utmp[0] &= kmask1;

        int sumi = 0;
        for (int j = 0; j < QK_K/16; ++j) sumi += y[i].bsums[j] * mins[j/2];
        a = aux8;
        int is = 0;
        for (int j = 0; j < QK_K/32; ++j) {
            int32_t scale = scales[is++];
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
        }
        const float d = GGML_FP16_TO_FP32(x[i].d) * y[i].d;
        for (int l = 0; l < 8; ++l) sums[l] += d * aux32[l];
        const float dmin = GGML_FP16_TO_FP32(x[i].dmin) * y[i].d;
        sumf -= dmin * sumi;
    }
    for (int l = 0; l < 8; ++l) sumf += sums[l];
    *s = sumf;
#endif
}

Here is a function. You need to convert it to WASM SIMD.

void ggml_vec_dot_q6_K_q8_K(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
    assert(n % QK_K == 0);
    assert(nrc == 1);
    UNUSED(nrc);
    UNUSED(bx);
    UNUSED(by);
    UNUSED(bs);

    const block_q6_K * restrict x = vx;
    const block_q8_K * restrict y = vy;

    const int nb = n / QK_K;

#ifdef __ARM_NEON
    float sum = 0;

    const uint8x16_t m4b = vdupq_n_u8(0xF);
    const int32x4_t  vzero = vdupq_n_s32(0);
    //const int8x16_t  m32s = vdupq_n_s8(32);

    const uint8x16_t mone = vdupq_n_u8(3);

    ggml_int8x16x4_t q6bytes;
    ggml_uint8x16x4_t q6h;

    for (int i = 0; i < nb; ++i) {

        const float d_all = GGML_FP16_TO_FP32(x[i].d);

        const uint8_t * restrict q6 = x[i].ql;
        const uint8_t * restrict qh = x[i].qh;
        const int8_t  * restrict q8 = y[i].qs;

        const int8_t * restrict scale = x[i].scales;

        const ggml_int16x8x2_t q8sums = ggml_vld1q_s16_x2(y[i].bsums);
        const int8x16_t scales = vld1q_s8(scale);
        const ggml_int16x8x2_t q6scales = {{vmovl_s8(vget_low_s8(scales)), vmovl_s8(vget_high_s8(scales))}};

        const int32x4_t prod = vaddq_s32(vaddq_s32(vmull_s16(vget_low_s16 (q8sums.val[0]), vget_low_s16 (q6scales.val[0])),
                                                   vmull_s16(vget_high_s16(q8sums.val[0]), vget_high_s16(q6scales.val[0]))),
                                         vaddq_s32(vmull_s16(vget_low_s16 (q8sums.val[1]), vget_low_s16 (q6scales.val[1])),
                                                   vmull_s16(vget_high_s16(q8sums.val[1]), vget_high_s16(q6scales.val[1]))));
        int32_t isum_mins = vaddvq_s32(prod);

        int32_t isum = 0;

        for (int j = 0; j < QK_K/128; ++j) {

            ggml_uint8x16x2_t qhbits = ggml_vld1q_u8_x2(qh); qh += 32;
            ggml_uint8x16x4_t q6bits = ggml_vld1q_u8_x4(q6); q6 += 64;
            ggml_int8x16x4_t q8bytes = ggml_vld1q_s8_x4(q8); q8 += 64;

            q6h.val[0] = vshlq_n_u8(vandq_u8(mone, qhbits.val[0]), 4);
            q6h.val[1] = vshlq_n_u8(vandq_u8(mone, qhbits.val[1]), 4);
            uint8x16_t shifted = vshrq_n_u8(qhbits.val[0], 2);
            q6h.val[2] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[1], 2);
            q6h.val[3] = vshlq_n_u8(vandq_u8(mone, shifted), 4);

            q6bytes.val[0] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[0], m4b), q6h.val[0]));
            q6bytes.val[1] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[1], m4b), q6h.val[1]));
            q6bytes.val[2] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[2], m4b), q6h.val[2]));
            q6bytes.val[3] = vreinterpretq_s8_u8(vorrq_u8(vandq_u8(q6bits.val[3], m4b), q6h.val[3]));

            isum += vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[0], q8bytes.val[0])) * scale[0] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[1], q8bytes.val[1])) * scale[1] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[2], q8bytes.val[2])) * scale[2] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[3], q8bytes.val[3])) * scale[3];

            scale += 4;

            q8bytes = ggml_vld1q_s8_x4(q8); q8 += 64;

            shifted = vshrq_n_u8(qhbits.val[0], 4);
            q6h.val[0] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[1], 4);
            q6h.val[1] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[0], 6);
            q6h.val[2] = vshlq_n_u8(vandq_u8(mone, shifted), 4);
            shifted = vshrq_n_u8(qhbits.val[1], 6);
            q6h.val[3] = vshlq_n_u8(vandq_u8(mone, shifted), 4);

            q6bytes.val[0] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[0], 4), q6h.val[0]));
            q6bytes.val[1] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[1], 4), q6h.val[1]));
            q6bytes.val[2] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[2], 4), q6h.val[2]));
            q6bytes.val[3] = vreinterpretq_s8_u8(vorrq_u8(vshrq_n_u8(q6bits.val[3], 4), q6h.val[3]));

            isum += vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[0], q8bytes.val[0])) * scale[0] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[1], q8bytes.val[1])) * scale[1] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[2], q8bytes.val[2])) * scale[2] +
                    vaddvq_s32(ggml_vdotq_s32(vzero, q6bytes.val[3], q8bytes.val[3])) * scale[3];
            scale += 4;
        }
        //sum += isum * d_all * y[i].d;
        sum += d_all * y[i].d * (isum - 32 * isum_mins);

    }
    *s = sum;

#elif defined __AVX__

    const __m128i m3 = _mm_set1_epi8(3);
    const __m128i m15 = _mm_set1_epi8(15);

    __m256 acc = _mm256_setzero_ps();

    for (int i = 0; i < nb; ++i) {

        const float d = y[i].d * GGML_FP16_TO_FP32(x[i].d);

        const uint8_t * restrict q4 = x[i].ql;
        const uint8_t * restrict qh = x[i].qh;
        const int8_t  * restrict q8 = y[i].qs;

        // handle the q6_k -32 offset separately using bsums
        const __m128i q8sums_0 = _mm_loadu_si128((const __m128i*)y[i].bsums);
        const __m128i q8sums_1 = _mm_loadu_si128((const __m128i*)y[i].bsums + 1);
        const __m128i scales = _mm_loadu_si128((const __m128i*)x[i].scales);
        const __m128i scales_16_0 = _mm_cvtepi8_epi16(scales);
        const __m128i scales_16_1 = _mm_cvtepi8_epi16(_mm_bsrli_si128(scales, 8));
        const __m128i q8sclsub_0 = _mm_slli_epi32(_mm_madd_epi16(q8sums_0, scales_16_0), 5);
        const __m128i q8sclsub_1 = _mm_slli_epi32(_mm_madd_epi16(q8sums_1, scales_16_1), 5);

        __m128i sumi_0 = _mm_setzero_si128();
        __m128i sumi_1 = _mm_setzero_si128();

        int is = 0;

        for (int j = 0; j < QK_K/128; ++j) {

            const __m128i q4bitsH_0 = _mm_loadu_si128((const __m128i*)qh); qh += 16;
            const __m128i q4bitsH_1 = _mm_loadu_si128((const __m128i*)qh); qh += 16;

            const __m128i q4h_0 = _mm_slli_epi16(_mm_and_si128(q4bitsH_0, m3), 4);
            const __m128i q4h_1 = _mm_slli_epi16(_mm_and_si128(q4bitsH_1, m3), 4);
            const __m128i q4h_2 = _mm_slli_epi16(_mm_and_si128(q4bitsH_0, _mm_set1_epi8(12)), 2);
            const __m128i q4h_3 = _mm_slli_epi16(_mm_and_si128(q4bitsH_1, _mm_set1_epi8(12)), 2);
            const __m128i q4h_4 = _mm_and_si128(q4bitsH_0, _mm_set1_epi8(48));
            const __m128i q4h_5 = _mm_and_si128(q4bitsH_1, _mm_set1_epi8(48));
            const __m128i q4h_6 = _mm_srli_epi16(_mm_and_si128(q4bitsH_0, _mm_set1_epi8(-64)), 2);
            const __m128i q4h_7 = _mm_srli_epi16(_mm_and_si128(q4bitsH_1, _mm_set1_epi8(-64)), 2);

            const __m128i q4bits1_0 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4bits1_1 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4bits2_0 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;
            const __m128i q4bits2_1 = _mm_loadu_si128((const __m128i*)q4); q4 += 16;

            const __m128i q4_0 = _mm_or_si128(_mm_and_si128(q4bits1_0, m15), q4h_0);
            const __m128i q4_1 = _mm_or_si128(_mm_and_si128(q4bits1_1, m15), q4h_1);
            const __m128i q4_2 = _mm_or_si128(_mm_and_si128(q4bits2_0, m15), q4h_2);
            const __m128i q4_3 = _mm_or_si128(_mm_and_si128(q4bits2_1, m15), q4h_3);
            const __m128i q4_4 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits1_0, 4), m15), q4h_4);
            const __m128i q4_5 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits1_1, 4), m15), q4h_5);
            const __m128i q4_6 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits2_0, 4), m15), q4h_6);
            const __m128i q4_7 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(q4bits2_1, 4), m15), q4h_7);

            const __m128i q8_0 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_1 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_2 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_3 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_4 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_5 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_6 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;
            const __m128i q8_7 = _mm_loadu_si128((const __m128i*)q8); q8 += 16;

            __m128i p16_0 = _mm_maddubs_epi16(q4_0, q8_0);
            __m128i p16_1 = _mm_maddubs_epi16(q4_1, q8_1);
            __m128i p16_2 = _mm_maddubs_epi16(q4_2, q8_2);
            __m128i p16_3 = _mm_maddubs_epi16(q4_3, q8_3);
            __m128i p16_4 = _mm_maddubs_epi16(q4_4, q8_4);
            __m128i p16_5 = _mm_maddubs_epi16(q4_5, q8_5);
            __m128i p16_6 = _mm_maddubs_epi16(q4_6, q8_6);
            __m128i p16_7 = _mm_maddubs_epi16(q4_7, q8_7);

            const __m128i scale_0 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 0));
            const __m128i scale_1 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 1));
            const __m128i scale_2 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 2));
            const __m128i scale_3 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 3));
            is += 4;

            p16_0 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_0), p16_0);
            p16_1 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_0, 8)), p16_1);
            p16_2 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_1), p16_2);
            p16_3 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_1, 8)), p16_3);
            p16_4 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_2), p16_4);
            p16_5 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_2, 8)), p16_5);
            p16_6 = _mm_madd_epi16(_mm_cvtepi8_epi16(scale_3), p16_6);
            p16_7 = _mm_madd_epi16(_mm_cvtepi8_epi16(_mm_bsrli_si128(scale_3, 8)), p16_7);

            sumi_0 = _mm_add_epi32(sumi_0, _mm_add_epi32(p16_0, p16_2));
            sumi_1 = _mm_add_epi32(sumi_1, _mm_add_epi32(p16_1, p16_3));
            sumi_0 = _mm_add_epi32(sumi_0, _mm_add_epi32(p16_4, p16_6));
            sumi_1 = _mm_add_epi32(sumi_1, _mm_add_epi32(p16_5, p16_7));

        }

        sumi_0 = _mm_sub_epi32(sumi_0, q8sclsub_0);
        sumi_1 = _mm_sub_epi32(sumi_1, q8sclsub_1);
        const __m256i sumi = MM256_SET_M128I(sumi_1, sumi_0);
        acc = _mm256_add_ps(_mm256_mul_ps(_mm256_set1_ps(d), _mm256_cvtepi32_ps(sumi)), acc);
    }

    *s = hsum_float_8(acc);

#else

    int8_t  aux8[QK_K];
    int16_t aux16[8];
    float   sums [8];
    int32_t aux32[8];
    memset(sums, 0, 8*sizeof(float));

    float sumf = 0;
    for (int i = 0; i < nb; ++i) {
        const uint8_t * restrict q4 = x[i].ql;
        const uint8_t * restrict qh = x[i].qh;
        const  int8_t * restrict q8 = y[i].qs;
        memset(aux32, 0, 8*sizeof(int32_t));
        int8_t * restrict a = aux8;
        for (int j = 0; j < QK_K; j += 128) {
            for (int l = 0; l < 32; ++l) {
                a[l +  0] = (int8_t)((q4[l +  0] & 0xF) | (((qh[l] >> 0) & 3) << 4)) - 32;
                a[l + 32] = (int8_t)((q4[l + 32] & 0xF) | (((qh[l] >> 2) & 3) << 4)) - 32;
                a[l + 64] = (int8_t)((q4[l +  0] >>  4) | (((qh[l] >> 4) & 3) << 4)) - 32;
                a[l + 96] = (int8_t)((q4[l + 32] >>  4) | (((qh[l] >> 6) & 3) << 4)) - 32;
            }
            a  += 128;
            q4 += 64;
            qh += 32;
        }
        a = aux8;
        int is = 0;
        for (int j = 0; j < QK_K/16; ++j) {
            int scale = x[i].scales[is++];
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
            for (int l = 0; l < 8; ++l) aux16[l] = q8[l] * a[l];
            for (int l = 0; l < 8; ++l) aux32[l] += scale * aux16[l];
            q8 += 8; a += 8;
        }
        const float d = GGML_FP16_TO_FP32(x[i].d) * y[i].d;
        for (int l = 0; l < 8; ++l) sums[l] += d * aux32[l];
    }
    for (int l = 0; l < 8; ++l) sumf += sums[l];
    *s = sumf;
#endif
}

You must start your code with #elif defined(__wasm_simd128__)

To think about it, you need to take into account both the refenrence code from ARM NEON and AVX implementation.

hjortholm commented Jan 29, 2025

Prompt for measuring performance and further enhancement:

objective: Determine the total performance gains from newly introduced optimizations and explore potential improvements.

Performance Gains:
How much speedup or efficiency is expected compared to the previous implementation?
Which metrics (e.g., execution time, memory usage, throughput) should be measured, and how?
What tools or methods (e.g., profilers, benchmark suites) will validate these performance improvements? 
Optimization Angles:
Are there further optimizations in algorithmic design, concurrency, or hardware-specific tuning?
Could different compiler options, instruction sets, or data layouts enhance results?
What trade-offs (e.g., code complexity vs. performance) might arise?
Expected Outcomes:
Provide guidance on short-term improvements and long-term enhancements to maintain high performance.
Outline any potential bottlenecks or corner cases that may limit gains

Performance Gains Analysis
1. Expected Speedup vs. Previous Implementation
Previous (1 block/iteration): Processed 32 elements (1 block) per iteration, with loop overhead for each block.

Optimized (2 blocks/iteration):

Loop Unrolling: Reduces loop overhead by ~50% (fewer branch checks).

SIMD Utilization: Processes 64 elements (2 blocks) in parallel, leveraging instruction-level parallelism.

Expected Gains:

10–20% speedup over the initial WASM SIMD version (1 block/iteration).

4–6× faster than scalar WebAssembly code (non-SIMD fallback).

2. Key Metrics to Measure
Metric How to Measure Relevance
Execution Time Time per ggml_vec_dot_q8_0_q8_0 call using high-resolution timers (e.g., performance.now()). Direct measure of optimization impact.
Throughput Elements processed per second (e.g., (n / execution_time) * 1e6). Quantifies SIMD efficiency.
SIMD Utilization Assembly inspection (e.g., wasm-dis tool) to confirm SIMD instructions dominate. Ensures vectorization isn’t hindered by data dependencies or misalignment.
Memory Bandwidth Profiler metrics (e.g., cache misses, load/store throughput via perf stat in native runtimes). Identifies bottlenecks in data access.
3. Validation Tools & Methods
WebAssembly Tools:

Chrome DevTools: Profile WebAssembly execution with the Performance panel.

WABT (WebAssembly Binary Toolkit): Inspect generated SIMD instructions.

V8 Flags: Use --experimental-wasm-simd to enforce SIMD optimizations.

Benchmark Suites:

Microbenchmarks with varying n (e.g., 512, 1024, 2048 elements) to test scaling.

Cross-validate with ARM NEON timings to compare against native performance.

Profilers:

Linux Perf: If running in a WASM-to-native environment (e.g., Wasmer/Wasmtime).

Emscripten’s --profiling: Generate function-level timing reports.

Optimization Angles

Algorithmic Improvements
Reduced 8→16-Bit Extension Overhead:

Explore fused 8-bit dot product approximations (if WebAssembly adds i32x4.dot_i8x16 in future).

Block Size Tuning:

Experiment with larger blocks (e.g., QK8_0=64) to amortize loop overhead, but balance with cache locality.

2. Concurrency
Web Workers:

Split n into chunks processed in parallel across threads (limited by WebAssembly’s threading support).

SIMD + Multithreading:

Combine thread-level parallelism (e.g., SharedArrayBuffer) with SIMD for large tensors.

Hardware-Specific Tuning
Memory Alignment:

Ensure block_q8_0 structs are 16-byte aligned for faster v128.load operations.

CPU-Specific Scheduling:

Use compiler hints (e.g., #pragma unroll in Emscripten) to optimize for pipelining.

Compiler & Data Layout
Compiler Flags:

-msimd128 -O3 (Emscripten) to maximize SIMD optimizations.

-flto for link-time optimizations.

Data Layout:

Structure-of-Arrays (SoA) for qs/d fields to improve prefetching.

Trade-Offs
Optimization Benefit Trade-Off
Loop Unrolling Reduces branch overhead. Increases code size; harder to maintain.
SIMD Register Pressure Maximizes parallelism. Risk of spilling to memory on constrained hardware.
Threading Utilizes multiple cores. Adds complexity; WebAssembly threading is still experimental.
Expected Outcomes
Short-Term Improvements
Validate Current Optimizations:

Confirm 10–20% gains over the 1-block/iteration WASM SIMD code with microbenchmarks.

Memory Alignment:

Enforce 16-byte alignment for block_q8_0 to avoid unaligned loads.

Compiler Tuning:

Test -O3 vs. -Os to balance speed and code size.

Long-Term Enhancements
WebAssembly Future Features:

Adopt wider SIMD (e.g., 256-bit) if standardized.

Leverage i8x16.dot instructions if added to the spec.

Algorithmic Hybridization:

Mix SIMD and scalar code for small n (e.g., n < 256).

WebGPU Integration:

Offload large dot products to GPU compute shaders.

Bottlenecks & Corner Cases
Memory Bandwidth:

If tensors exceed L2 cache, SIMD gains may plateau. Use smaller blocks or tiling.

Odd Block Counts:

The fallback loop for residual blocks (ib < nb) adds minor overhead. Ensure it’s minimal.

Half-Precision Scaling:

GGML_FP16_TO_FP32 conversions are scalar; batch-convert d values upfront if possible.

Final Guidance
Immediate Next Steps:

Benchmark with real-world LLM inference workloads (e.g., a transformer layer).

Profile memory alignment impact using wasm-opt --align-features.

Future Roadmap:

Monitor WebAssembly SIMD evolution (e.g., relaxed SIMD proposals).

Explore WebGPU for heterogeneous compute in parallel with SIMD.

By balancing SIMD efficiency, loop unrolling, and memory optimizations, the current implementation achieves near-native performance for WebAssembly while leaving room for future gains as the ecosystem matures.