diff --git a/ext/json/ext/generator/generator.c b/ext/json/ext/generator/generator.c
index 04cc6e7b..882d47a6 100644
--- a/ext/json/ext/generator/generator.c
+++ b/ext/json/ext/generator/generator.c
@@ -842,12 +842,8 @@ static inline bool valid_json_string_p(VALUE str)
     return false;
 }
 
-static inline VALUE ensure_valid_encoding(struct generate_json_data *data, VALUE str, bool as_json_called, bool is_key)
+NOINLINE(static) VALUE convert_invalid_encoding(struct generate_json_data *data, VALUE str, bool as_json_called, bool is_key)
 {
-    if (RB_LIKELY(valid_json_string_p(str))) {
-        return str;
-    }
-
     if (!as_json_called && data->state->strict && RTEST(data->state->as_json)) {
         VALUE coerced_str = json_call_as_json(data->state, str, Qfalse);
         if (coerced_str != str) {
@@ -883,6 +879,16 @@ static inline VALUE ensure_valid_encoding(struct generate_json_data *data, VALUE
     return rb_rescue(encode_json_string_try, str, encode_json_string_rescue, str);
 }
 
+ALWAYS_INLINE(static) VALUE ensure_valid_encoding(struct generate_json_data *data, VALUE str, bool as_json_called, bool is_key)
+{
+    if (RB_LIKELY(valid_json_string_p(str))) {
+        return str;
+    }
+    else {
+        return convert_invalid_encoding(data, str, as_json_called, is_key);
+    }
+}
+
 static void raw_generate_json_string(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
 {
     fbuffer_append_char(buffer, '"');