diff --git a/lib/libstereo/src/filters/salient_gradient.hpp b/lib/libstereo/src/filters/salient_gradient.hpp
index 10ca19b114426a177491ea2100d28a386c09e9f8..43454264f3bf455bee1913718b13343c9c6ffd8e 100644
--- a/lib/libstereo/src/filters/salient_gradient.hpp
+++ b/lib/libstereo/src/filters/salient_gradient.hpp
@@ -70,7 +70,7 @@ struct SalientGradient {
 	}
 
 	__device__ void operator()(ushort2 thread, ushort2 stride, ushort2 size, WarpSharedMemory &wsm) {
-		static const float PI = 3.14f;
+		static constexpr float PI = 3.14f;
 		static constexpr float PI2 = PI/2.0f;
 
 		for (int y=thread.y; y<size.y; y+=stride.y) {
@@ -177,7 +177,7 @@ struct SalientGradientGrouped {
 	}
 
 	__device__ void operator()(ushort2 thread, ushort2 stride, ushort2 size, WarpSharedMemory &wsm) {
-		static const float PI = 3.14f;
+		static constexpr float PI = 3.14f;
 		static constexpr float PI2 = PI/2.0f;
 
 		for (int y=thread.y; y<size.y; y+=stride.y) {