diff --git a/src/arch/dotproduct.cpp b/src/arch/dotproduct.cpp
index 9a0e5cb6f9..daba2ff25b 100644
--- a/src/arch/dotproduct.cpp
+++ b/src/arch/dotproduct.cpp
@@ -22,7 +22,7 @@ namespace tesseract {
 template <class TFloat>
 TFloat DotProductNative(const TFloat *u, const TFloat *v, int n) {
   TFloat total = 0;
-#if defined(OPENMP_SIMD)
+#if defined(OPENMP_SIMD) || defined(_OPENMP)
 #pragma omp simd reduction(+:total)
 #endif
   for (int k = 0; k < n; k++) {