diff --git a/gc.c b/gc.c
index 6e32997b8e..2b9d5b1029 100644
--- a/gc.c
+++ b/gc.c
@@ -8110,20 +8110,25 @@ ruby_mimfree(void *ptr)
     free(mem);
 }
 
+rb_imemo_alloc_t *
+rb_imemo_alloc_new(VALUE v1, VALUE v2, VALUE v3, VALUE v0)
+{
+    VALUE s = rb_imemo_new(imemo_alloc, v1, v2, v3, v0);
+    rb_gc_writebarrier_unprotect(s);
+    return (rb_imemo_alloc_t *)s;
+}
+
 void *
 rb_alloc_tmp_buffer_with_count(volatile VALUE *store, size_t size, size_t cnt)
 {
-    VALUE s;
-    rb_imemo_alloc_t *a;
+    rb_imemo_alloc_t *s;
     void *ptr;
 
-    s = rb_imemo_new(imemo_alloc, 0, 0, 0, 0);
-    rb_gc_writebarrier_unprotect(s);
+    s = rb_imemo_alloc_new(0, 0, 0, 0);
     ptr = ruby_xmalloc0(size);
-    a = (rb_imemo_alloc_t*)s;
-    a->ptr = (VALUE*)ptr;
-    a->cnt = cnt;
-    *store = s;
+    s->ptr = (VALUE*)ptr;
+    s->cnt = cnt;
+    *store = (VALUE)s;
     return ptr;
 }
 
diff --git a/internal.h b/internal.h
index 743e83187c..401dfa5c74 100644
--- a/internal.h
+++ b/internal.h
@@ -938,6 +938,8 @@ typedef struct rb_imemo_alloc_struct {
     size_t cnt; /* buffer size in VALUE */
 } rb_imemo_alloc_t;
 
+rb_imemo_alloc_t *rb_imemo_alloc_new(VALUE, VALUE, VALUE, VALUE);
+
 /*! MEMO
  *
  * @see imemo_type
diff --git a/parse.y b/parse.y
index 7a5b680da0..27611d5f46 100644
--- a/parse.y
+++ b/parse.y
@@ -11528,7 +11528,7 @@ rb_parser_set_yydebug(VALUE self, VALUE flag)
 #ifndef RIPPER
 #ifdef YYMALLOC
 #define HEAPCNT(n, size) ((n) * (size) / sizeof(YYSTYPE))
-#define NEWHEAP() (rb_imemo_alloc_t *)rb_imemo_new(imemo_alloc, 0, (VALUE)parser->heap, 0, 0)
+#define NEWHEAP() rb_imemo_alloc_new(0, (VALUE)parser->heap, 0, 0)
 #define ADD2HEAP(n, c, p) ((parser->heap = (n))->ptr = (p), \
 			   (n)->cnt = (c), (p))
 
@@ -11538,7 +11538,6 @@ rb_parser_malloc(struct parser_params *parser, size_t size)
     size_t cnt = HEAPCNT(1, size);
     rb_imemo_alloc_t *n = NEWHEAP();
     void *ptr = xmalloc(size);
-    rb_gc_writebarrier_unprotect((VALUE)n);
 
     return ADD2HEAP(n, cnt, ptr);
 }
@@ -11549,7 +11548,6 @@ rb_parser_calloc(struct parser_params *parser, size_t nelem, size_t size)
     size_t cnt = HEAPCNT(nelem, size);
     rb_imemo_alloc_t *n = NEWHEAP();
     void *ptr = xcalloc(nelem, size);
-    rb_gc_writebarrier_unprotect((VALUE)n);
 
     return ADD2HEAP(n, cnt, ptr);
 }
@@ -11571,7 +11569,6 @@ rb_parser_realloc(struct parser_params *parser, void *ptr, size_t size)
     }
     n = NEWHEAP();
     ptr = xrealloc(ptr, size);
-    rb_gc_writebarrier_unprotect((VALUE)n);
     return ADD2HEAP(n, cnt, ptr);
 }