diff --git a/compile.c b/compile.c
index 0e3abd71f7..2962bc8e34 100644
--- a/compile.c
+++ b/compile.c
@@ -29,9 +29,6 @@
 #undef RUBY_UNTYPED_DATA_WARNING
 #define RUBY_UNTYPED_DATA_WARNING 0
 
-rb_control_frame_t *
-  FUNC_FASTCALL(rb_vm_str_intern)(rb_thread_t *, rb_control_frame_t *);
-
 #define ISEQ_TYPE_ONCE_GUARD ISEQ_TYPE_DEFINED_GUARD
 
 #define FIXNUM_INC(n, i) ((n)+(INT2FIX(i)&~FIXNUM_FLAG))
@@ -6582,7 +6579,7 @@ iseq_compile_each0(rb_iseq_t *iseq, LINK_ANCHOR *const ret, NODE *node, int popp
       case NODE_DSYM:{
 	compile_dstr(iseq, ret, node);
 	if (!popped) {
-	    ADD_INSN1(ret, line, opt_call_c_function, rb_vm_str_intern);
+	    ADD_INSN(ret, line, intern);
 	}
 	else {
 	    ADD_INSN(ret, line, pop);
diff --git a/insns.def b/insns.def
index 1b069ce37d..bd47c2c0b0 100644
--- a/insns.def
+++ b/insns.def
@@ -398,6 +398,20 @@ toregexp
     rb_ary_clear(ary);
 }
 
+/**
+  @c put
+  @e intern str to Symbol and push it.
+  @j 文字列 str をシンボルに変換してスタックにプッシュする。
+ */
+DEFINE_INSN
+intern
+()
+(VALUE str)
+(VALUE sym)
+{
+    sym = rb_str_intern(str);
+}
+
 /**
   @c put
   @e put new array initialized with num values on the stack.
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index d11529ed75..1678100eab 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -2794,13 +2794,6 @@ FUNC_FASTCALL(rb_vm_opt_struct_aset)(rb_thread_t *th, rb_control_frame_t *reg_cf
     return reg_cfp;
 }
 
-rb_control_frame_t *
-FUNC_FASTCALL(rb_vm_str_intern)(rb_thread_t *th, rb_control_frame_t *reg_cfp)
-{
-    TOPN(0) = rb_str_intern(TOPN(0));
-    return reg_cfp;
-}
-
 /* defined insn */
 
 static enum defined_type