diff --git a/modules/dnn/src/layers/fast_convolution/fast_convolution.hpp b/modules/dnn/src/layers/fast_convolution/fast_convolution.hpp
index eda5c7ce26..ba85077f70 100644
--- a/modules/dnn/src/layers/fast_convolution/fast_convolution.hpp
+++ b/modules/dnn/src/layers/fast_convolution/fast_convolution.hpp
@@ -21,7 +21,7 @@ enum { FAST_VEC_NLANES=4 };
 #define CONV_MR 4
 #define CONV_NR 24
 
-#ifdef CV_AVX2
+#if CV_AVX2
 enum { FAST_VEC_NLANES=8 }; // AVX2
 #else
 enum { FAST_VEC_NLANES=4 }; // SIMD 128