diff --git a/3rdparty/astc-encoder/source/astcenc_vecmathlib_sse_4.h b/3rdparty/astc-encoder/source/astcenc_vecmathlib_sse_4.h
index 76fe577..9025f80 100644
--- a/3rdparty/astc-encoder/source/astcenc_vecmathlib_sse_4.h
+++ b/3rdparty/astc-encoder/source/astcenc_vecmathlib_sse_4.h
@@ -1275,7 +1275,11 @@ ASTCENC_SIMD_INLINE vfloat4 dot3(vfloat4 a, vfloat4 b)
  */
 ASTCENC_SIMD_INLINE int popcount(uint64_t v)
 {
+#if defined(__MINGW32__)
+	return static_cast<int>(__builtin_popcountll(v));
+#else
 	return static_cast<int>(_mm_popcnt_u64(v));
+#endif // defined(__MINGW32__)
 }
 
 #endif // ASTCENC_POPCNT >= 1
diff --git a/src/image.cpp b/src/image.cpp
index 63d4625..4cb3b9a 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -5805,7 +5805,7 @@ namespace bimg
 			return total;
 		}
 
-		for (uint8_t side = 0, numSides = _imageContainer.m_numLayers * (_imageContainer.m_cubeMap ? 6 : 1); side < numSides && _err->isOk(); ++side)
+		for (uint8_t side = 0, numSides = uint8_t(_imageContainer.m_numLayers * (_imageContainer.m_cubeMap ? 6 : 1) ); side < numSides && _err->isOk(); ++side)
 		{
 			for (uint8_t lod = 0, num = _imageContainer.m_numMips; lod < num && _err->isOk(); ++lod)
 			{