diff --git a/include/qphix/dslash_utils.h b/include/qphix/dslash_utils.h
index cd497a10..f0563f51 100644
--- a/include/qphix/dslash_utils.h
+++ b/include/qphix/dslash_utils.h
@@ -66,7 +66,7 @@ struct BlockPhase {
   int cid_yz;
 };
 
-inline void *aligned_malloc(int size, int alignment)
+inline void *aligned_malloc(size_t size, int alignment)
 {
   void *v;
   int ok;