do not use fake intrinsics

1 files changed, 3 insertions, 1 deletions

diff --git a/multiply.h b/multiply.h
index ee2196e..50f548b 100644
--- a/multiply.h
+++ b/multiply.h
@@ -81,7 +81,9 @@ static inline INTGEMM_AVX512F float MaxFloat32(__m512 a) {
 }
 
 static inline INTGEMM_AVX512F float horizontalSum(__m512 a) {
-  return _mm512_reduce_add_ps(a);
+  __m256 low  = _mm512_castps512_ps256(a);
+  __m256 high = _mm256_castpd_ps(_mm512_extractf64x4_pd(_mm512_castps_pd(a),1));
+  return horizontalSum(low) + horizontalSum(high);
 }
 
 #endif