diff --git a/ChangeLog b/ChangeLog
index d12e536b50..2a14677b7a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Jan 17 12:32:46 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* gc.c (aligned_malloc, aligned_free): covered missing defined
+	  operators and fixes for cygwin.
+
 Tue Jan 17 10:54:46 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* st.c (do_hash): it's the time to remove cast to unsigned int.
diff --git a/gc.c b/gc.c
index 5aac9738e3..4c906e7ab2 100644
--- a/gc.c
+++ b/gc.c
@@ -1088,9 +1088,9 @@ aligned_malloc(size_t alignment, size_t size)
 {
     void *res;
 
-#if __MINGW32__
+#if defined __MINGW32__
     res = __mingw_aligned_malloc(size, alignment);
-#elif _WIN32 || defined __CYGWIN__
+#elif defined _WIN32 && !defined __CYGWIN__
     res = _aligned_malloc(size, alignment);
 #elif defined(HAVE_POSIX_MEMALIGN)
     if (posix_memalign(&res, alignment, size) == 0) {
@@ -1109,9 +1109,9 @@ aligned_malloc(size_t alignment, size_t size)
 static void
 aligned_free(void *ptr)
 {
-#if __MINGW32__
+#if defined __MINGW32__
     __mingw_aligned_free(ptr);
-#elif _WIN32 || defined __CYGWIN__
+#elif defined _WIN32 && !defined __CYGWIN__
     _aligned_free(ptr);
 #else
     free(ptr);