diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index 09769d5e80a4427b364410426add28a3d820c3b7..a32abf3ab9479a9421c4493871a3701821bf1515 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -1646,7 +1646,7 @@ LLVector3 LLVOVolume::getApproximateFaceNormal(U8 face_id)
 	if (volume && face_id < volume->getNumVolumeFaces())
 	{
 		const LLVolumeFace& face = volume->getVolumeFace(face_id);
-		for (S32 i = 0; i < face.mVertices.size(); ++i)
+		for (S32 i = 0; i < (S32)face.mVertices.size(); ++i)
 		{
 			result += face.mVertices[i].mNormal;
 		}