diff --git a/include/wx/msw/genrcdefs.h b/include/wx/msw/genrcdefs.h
index 13a792458d..809419b3f9 100644
--- a/include/wx/msw/genrcdefs.h
+++ b/include/wx/msw/genrcdefs.h
@@ -19,7 +19,7 @@ EMIT(#define wxUSE_RC_MANIFEST 1)
 EMIT(#define wxUSE_RC_MANIFEST 1)
 #endif
 
-#ifdef _M_AMD64 || defined __x86_64__
+#if defined _M_AMD64 || defined __x86_64__
 EMIT(#define WX_CPU_AMD64)
 #endif
 
@@ -27,7 +27,7 @@ EMIT(#define WX_CPU_AMD64)
 EMIT(#define WX_CPU_ARM)
 #endif
 
-#ifdef _M_IA64 || defined __ia64__
+#if defined _M_IA64 || defined __ia64__
 EMIT(#define WX_CPU_IA64)
 #endif