diff --git a/aom_mem/aom_mem.h b/aom_mem/aom_mem.h
index f533ab9..bc5d8bc 100644
--- a/aom_mem/aom_mem.h
+++ b/aom_mem/aom_mem.h
@@ -40,7 +40,7 @@
 
 /*returns an addr aligned to the byte boundary specified by align*/
 #define aom_align_addr(addr, align) \
-  (void *)(((size_t)(addr) + ((align)-1)) & ~(size_t)((align)-1))
+  (void *)(((uintptr_t)(addr) + ((align)-1)) & ~(uintptr_t)((align)-1))
 
 #include <string.h>