diff --git a/ChangeLog b/ChangeLog
index 4da62af8f6..4cd01e9d9a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Mar 28 09:52:33 2001  WATANABE Hirofumi  <eban@ruby-lang.org>
+
+	* win32/Makefile.sub: disable global optimization.
+
 Tue Mar 27 15:00:54 2001  K.Kosako  <kosako@sofnec.co.jp>
 
 	* eval.c (rb_mod_define_method): should have clear method cache.
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 227ab68b18..e5ce57f726 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -30,7 +30,7 @@ AUTOCONF = autoconf
 
 
 prefix = /usr
-CFLAGS = -nologo -DNT=1 -Zi -MD -O2b2x -G5
+CFLAGS = -nologo -DNT=1 -Zi -MD -O2b2xg- -G5
 CPPFLAGS = -I$(srcdir) -I$(srcdir)/missing
 LDFLAGS = $(CFLAGS) -Fm
 XLDFLAGS =