diff squared

Author: dor-forer

src/VecSim/spaces/L2/L2_AVX2_FMA_SQ8.h

@@ -31,10 +31,9 @@ static inline void L2StepSQ8_FMA(const float *&pVect1, const uint8_t *&pVect2, _
 
     // Calculate squared difference - simple and efficient approach
     __m256 diff = _mm256_sub_ps(v1, v2_dequant);
-    __m256 diff_squared = _mm256_mul_ps(diff, diff);
-
-    // Add to running sum
-    sum256 = _mm256_add_ps(sum256, diff_squared);
+    
+    // Use FMA for diff² + sum in one instruction
+    sum256 = _mm256_fmadd_ps(diff, diff, sum256);
 }
 
 template <unsigned char residual> // 0..15