diff --git a/ChangeLog b/ChangeLog
index 57feff07e5..3c706b5db8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Feb 10 01:29:05 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/dl/dl.h (DLALIGN): round up at once and get rid of overflow.
+
 Fri Feb 10 00:47:07 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* test/ruby/envutil.rb (assert_no_memory_leak): new assertion to
diff --git a/ext/dl/dl.h b/ext/dl/dl.h
index 90e2131ee2..d0a461f921 100644
--- a/ext/dl/dl.h
+++ b/ext/dl/dl.h
@@ -155,9 +155,8 @@ typedef struct { char c; LONG_LONG x; } s_long_long;
 #define ALIGN_FLOAT  (sizeof(s_float) - sizeof(float))
 #define ALIGN_DOUBLE (sizeof(s_double) - sizeof(double))
 
-#define DLALIGN(ptr,offset,align) {\
-  while( (((unsigned long)((char *)(ptr) + (offset))) % (align)) != 0 ) (offset)++;\
-}
+#define DLALIGN(ptr,offset,align) \
+    ((offset) += ((align) - ((uintptr_t)((char *)(ptr) + (offset))) % (align)) % (align))
 
 
 #define DLTYPE_VOID  0