diff --git a/src/libslic3r/Utils.hpp b/src/libslic3r/Utils.hpp
index 98c15db3c..8feb17747 100644
--- a/src/libslic3r/Utils.hpp
+++ b/src/libslic3r/Utils.hpp
@@ -116,10 +116,12 @@ inline uint64_t next_highest_power_of_2(uint64_t v)
 // gives a duplicate symbol error.
 inline size_t next_highest_power_of_2(size_t v)
 { 
-#if sizeof(size_t) == sizeof(uint32_t)
-    return next_highest_power_of_2(uint32_t(v));
-#else
+#if SSIZE_MAX == 9223372036854775807
+    static_assert(sizeof(size_t) == sizeof(uint64_t));
     return next_highest_power_of_2(uint64_t(v));
+#else
+    static_assert(sizeof(size_t) == sizeof(uint32_t));
+    return next_highest_power_of_2(uint32_t(v));
 #endif
 }
 #endif