diff --git a/include/mitsuba/core/rfilter.h b/include/mitsuba/core/rfilter.h
index b4bfa902..6ab209b9 100644
--- a/include/mitsuba/core/rfilter.h
+++ b/include/mitsuba/core/rfilter.h
@@ -124,7 +124,7 @@ template <typename Scalar> struct Resampler {
 			int sourceRes, int targetRes) : m_bc(bc), m_sourceRes(sourceRes), m_targetRes(targetRes),
 			m_start(NULL), m_weights(NULL) {
 		SAssert(sourceRes > 0 && targetRes > 0);
-		Float filterRadius = rfilter->getRadius(), scale = 1.0f, invScale = 1.0f;
+		Float filterRadius = rfilter->getRadius(), scale = (Float)1.0, invScale = (Float)1.0;
 
 		/* Low-pass filter: scale reconstruction filters when downsampling */
 		if (targetRes < sourceRes) {
diff --git a/src/mtsgui/simdtonemap.cpp b/src/mtsgui/simdtonemap.cpp
index 89979682..28d7d9a1 100644
--- a/src/mtsgui/simdtonemap.cpp
+++ b/src/mtsgui/simdtonemap.cpp
@@ -520,13 +520,13 @@ bool luminance(const mitsuba::Bitmap* source, const float multiplier,
 		V4i tailMask = V4i::zero();
 		switch (pixelCount % 4) {
 		case 1:
-			tailMask = V4i::constant<0, 0x00000000, 0x00000000, 0xffffffff>();
+			tailMask = V4i::constant<0, 0, 0, -1>();
 			break;
 		case 2:
-			tailMask = V4i::constant<0, 0x00000000, 0xffffffff, 0xffffffff>();
+			tailMask = V4i::constant<0, 0, -1, -1>();
 			break;
 		case 3:
-			tailMask = V4i::constant<0, 0xffffffff, 0xffffffff, 0xffffffff>();
+			tailMask = V4i::constant<0, -1, -1, -1>();
 			break;
 		}
 		// maxLuminance contains zeros in the invalid positions which is OK