diff --git a/compile.c b/compile.c
index 08895134bd..17f870e3e5 100644
--- a/compile.c
+++ b/compile.c
@@ -10713,7 +10713,7 @@ typedef unsigned int ibf_offset_t;
 #define IBF_OFFSET(ptr) ((ibf_offset_t)(VALUE)(ptr))
 
 #define IBF_MAJOR_VERSION ISEQ_MAJOR_VERSION
-#if RUBY_DEVEL
+#ifdef RUBY_DEVEL
 #define IBF_DEVEL_VERSION 4
 #define IBF_MINOR_VERSION (ISEQ_MINOR_VERSION * 10000 + IBF_DEVEL_VERSION)
 #else
diff --git a/main.c b/main.c
index e76228713f..0d0ec147cd 100644
--- a/main.c
+++ b/main.c
@@ -23,7 +23,7 @@
 #ifdef HAVE_LOCALE_H
 #include <locale.h>
 #endif
-#if RUBY_DEVEL && !defined RUBY_DEBUG_ENV
+#if defined RUBY_DEVEL && !defined RUBY_DEBUG_ENV
 # define RUBY_DEBUG_ENV 1
 #endif
 #if defined RUBY_DEBUG_ENV && !RUBY_DEBUG_ENV