iq1_m: faster ARM_NEON dot product

11.65 t/s -> 14.9 t/s

Author: Kawrakow

ggml-quants.c

@@ -9763,12 +9763,16 @@ void ggml_vec_dot_iq1_m_q8_K  (int n, float * restrict s, size_t bs, const void
 
 #if defined __ARM_NEON
 
-    const int8x8_t minus1 = vdup_n_s8(-1);
-    const int8x8_t plus1  = vdup_n_s8(+1);
     const int32x4_t mask  = vdupq_n_s32(0x7);
     const int32x4_t mone  = vdupq_n_s32(1);
     const int32x4_t mzero = vdupq_n_s32(0);
 
+    ggml_int8x16x4_t deltas;
+    deltas.val[0] = vcombine_s8(vdup_n_s8(+1), vdup_n_s8(+1));
+    deltas.val[1] = vcombine_s8(vdup_n_s8(-1), vdup_n_s8(+1));
+    deltas.val[2] = vcombine_s8(vdup_n_s8(+1), vdup_n_s8(-1));
+    deltas.val[3] = vcombine_s8(vdup_n_s8(-1), vdup_n_s8(-1));
+
     ggml_int8x16x4_t q1b;
     ggml_int8x16x4_t q8b;
     ggml_int8x16x4_t delta;
@@ -9805,10 +9809,10 @@ void ggml_vec_dot_iq1_m_q8_K  (int n, float * restrict s, size_t bs, const void
             const int32x4_t p2 = vpaddq_s32(ggml_vdotq_s32(mzero, q1b.val[2], q8b.val[2]), ggml_vdotq_s32(mzero, q1b.val[3], q8b.val[3]));
             const int32x4_t p12 = vpaddq_s32(p1, p2);
 
-            delta.val[0] = vcombine_s8(qh[0] & 0x08 ? minus1 : plus1, qh[0] & 0x80 ? minus1 : plus1);
-            delta.val[1] = vcombine_s8(qh[1] & 0x08 ? minus1 : plus1, qh[1] & 0x80 ? minus1 : plus1);
-            delta.val[2] = vcombine_s8(qh[2] & 0x08 ? minus1 : plus1, qh[2] & 0x80 ? minus1 : plus1);
-            delta.val[3] = vcombine_s8(qh[3] & 0x08 ? minus1 : plus1, qh[3] & 0x80 ? minus1 : plus1);
+            delta.val[0] = deltas.val[((qh[0] & 0x08) >> 3) | ((qh[0] & 0x80) >> 6)];
+            delta.val[1] = deltas.val[((qh[1] & 0x08) >> 3) | ((qh[1] & 0x80) >> 6)];
+            delta.val[2] = deltas.val[((qh[2] & 0x08) >> 3) | ((qh[2] & 0x80) >> 6)];
+            delta.val[3] = deltas.val[((qh[3] & 0x08) >> 3) | ((qh[3] & 0x80) >> 6)];
 
             const int32x4_t p3 = vpaddq_s32(ggml_vdotq_s32(mzero, delta.val[0], q8b.val[0]), ggml_vdotq_s32(mzero, delta.val[1], q8b.val[1]));
             const int32x4_t p4 = vpaddq_s32(ggml_vdotq_s32(mzero, delta.val[2], q8b.val[2]), ggml_vdotq_s32(mzero, delta.val[3], q8b.val[3]));