diff --git a/mozglue/misc/StackWalk.cpp b/mozglue/misc/StackWalk.cpp
index e064eb4766c..bdca7d3882a 100644
--- a/mozglue/misc/StackWalk.cpp
+++ b/mozglue/misc/StackWalk.cpp
@@ -1073,7 +1073,7 @@ FramePointerStackWalk(MozWalkStackCallback aCallback, uint32_t aSkipFrames,
     // we can assume that bp > sp
     if (next <= bp ||
         next > aStackEnd ||
-        (long(next) & 3)) {
+        (uintptr_t(next) & 3)) {
       break;
     }
 #if (defined(__ppc__) && defined(XP_MACOSX)) || defined(__powerpc64__)