diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 3a0c1cf3dd..38c767d5be 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -1197,8 +1197,8 @@ vm_callee_setup_arg_complex(rb_thread_t *th, rb_call_info_t *ci, const rb_iseq_t
 }
 
 static VALUE vm_call_iseq_setup_2(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
-static VALUE vm_call_iseq_setup_normal(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
-static VALUE vm_call_iseq_setup_tailcall(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
+static inline VALUE vm_call_iseq_setup_normal(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
+static inline VALUE vm_call_iseq_setup_tailcall(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
 
 #define VM_CALLEE_SETUP_ARG(th, ci, iseq, argv, is_lambda) \
     if (LIKELY((iseq)->arg_simple & 0x01)) { \
@@ -1574,7 +1574,7 @@ vm_call_bmethod(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
     return vm_call_bmethod_body(th, ci, argv);
 }
 
-static VALUE vm_call_method(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
+static inline VALUE vm_call_method(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
 
 static VALUE
 vm_call_opt_send(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)