diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-regexp-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-regexp-prototype.c
index 7946f5471..da9d7e625 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-regexp-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-regexp-prototype.c
@@ -159,28 +159,7 @@ ecma_builtin_regexp_prototype_compile (ecma_value_t this_arg, /**< this argument
       ecma_string_t *pattern_string_p = NULL;
 
       /* Get source string. */
-      if (!ecma_is_value_undefined (pattern_arg))
-      {
-        ECMA_TRY_CATCH (regexp_str_value,
-                        ecma_op_to_string (pattern_arg),
-                        ret_value);
-
-        if (ecma_string_is_empty (ecma_get_string_from_value (regexp_str_value)))
-        {
-          pattern_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_EMPTY_NON_CAPTURE_GROUP);
-        }
-        else
-        {
-          pattern_string_p = ecma_get_string_from_value (regexp_str_value);
-          ecma_ref_ecma_string (pattern_string_p);
-        }
-
-        ECMA_FINALIZE (regexp_str_value);
-      }
-      else
-      {
-        pattern_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_EMPTY_NON_CAPTURE_GROUP);
-      }
+      ret_value = ecma_regexp_read_pattern_str_helper (pattern_arg, &pattern_string_p);
 
       /* Parse flags. */
       if (ecma_is_value_empty (ret_value) && !ecma_is_value_undefined (flags_arg))
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-regexp.c b/jerry-core/ecma/builtin-objects/ecma-builtin-regexp.c
index 469833299..b897a0b66 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-regexp.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-regexp.c
@@ -96,28 +96,7 @@ ecma_builtin_regexp_dispatch_construct (const ecma_value_t *arguments_list_p, /*
     ecma_string_t *pattern_string_p = NULL;
     ecma_string_t *flags_string_p = NULL;
 
-    if (!ecma_is_value_undefined (pattern_value))
-    {
-      ECMA_TRY_CATCH (regexp_str_value,
-                      ecma_op_to_string (pattern_value),
-                      ret_value);
-
-      if (ecma_string_is_empty (ecma_get_string_from_value (regexp_str_value)))
-      {
-        pattern_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_EMPTY_NON_CAPTURE_GROUP);
-      }
-      else
-      {
-        pattern_string_p = ecma_get_string_from_value (regexp_str_value);
-        ecma_ref_ecma_string (pattern_string_p);
-      }
-
-      ECMA_FINALIZE (regexp_str_value);
-    }
-    else
-    {
-      pattern_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_EMPTY_NON_CAPTURE_GROUP);
-    }
+    ret_value = ecma_regexp_read_pattern_str_helper (pattern_value, &pattern_string_p);
 
     if (ecma_is_value_empty (ret_value) && !ecma_is_value_undefined (flags_value))
     {
diff --git a/jerry-core/ecma/operations/ecma-regexp-object.c b/jerry-core/ecma/operations/ecma-regexp-object.c
index 6ab090927..bb3ca9883 100644
--- a/jerry-core/ecma/operations/ecma-regexp-object.c
+++ b/jerry-core/ecma/operations/ecma-regexp-object.c
@@ -1427,6 +1427,44 @@ ecma_regexp_exec_helper (ecma_value_t regexp_value, /**< RegExp object */
   return ret_value;
 } /* ecma_regexp_exec_helper */
 
+/**
+ * Helper function for converting a RegExp pattern parameter to string.
+ *
+ * See also:
+ *         RegExp.compile
+ *         RegExp dispatch call
+ *
+ * @return empty value if success, error value otherwise
+ *         Returned value must be freed with ecma_free_value.
+ */
+ecma_value_t
+ecma_regexp_read_pattern_str_helper (ecma_value_t pattern_arg, /**< the RegExp pattern */
+                                     ecma_string_t **pattern_string_p) /**< [out] ptr to the pattern string ptr */
+{
+  if (!ecma_is_value_undefined (pattern_arg))
+  {
+    ecma_value_t regexp_str_value = ecma_op_to_string (pattern_arg);
+    if (ECMA_IS_VALUE_ERROR (regexp_str_value))
+    {
+      return regexp_str_value;
+    }
+
+    *pattern_string_p = ecma_get_string_from_value (regexp_str_value);
+    if (!ecma_string_is_empty (*pattern_string_p))
+    {
+      ecma_ref_ecma_string (*pattern_string_p);
+    }
+
+    ecma_free_value (regexp_str_value); // must be freed *after* ecma_ref_ecma_string
+  }
+
+  if (!*pattern_string_p || ecma_string_is_empty (*pattern_string_p))
+  {
+    *pattern_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_EMPTY_NON_CAPTURE_GROUP);
+  }
+  return ECMA_VALUE_EMPTY;
+} /* ecma_regexp_read_pattern_str_helper */
+
 /**
  * @}
  * @}
diff --git a/jerry-core/ecma/operations/ecma-regexp-object.h b/jerry-core/ecma/operations/ecma-regexp-object.h
index ccefe993b..97e94cb7e 100644
--- a/jerry-core/ecma/operations/ecma-regexp-object.h
+++ b/jerry-core/ecma/operations/ecma-regexp-object.h
@@ -55,6 +55,7 @@ typedef struct
 ecma_value_t ecma_op_create_regexp_object_from_bytecode (re_compiled_code_t *bytecode_p);
 ecma_value_t ecma_op_create_regexp_object (ecma_string_t *pattern_p, ecma_string_t *flags_str_p);
 ecma_value_t ecma_regexp_exec_helper (ecma_value_t regexp_value, ecma_value_t input_string, bool ignore_global);
+ecma_value_t ecma_regexp_read_pattern_str_helper (ecma_value_t pattern_arg, ecma_string_t **pattern_string_p);
 ecma_char_t re_canonicalize (ecma_char_t ch, bool is_ignorecase);
 void re_set_result_array_properties (ecma_object_t *array_obj_p, ecma_string_t *input_str_p, uint32_t num_of_elements,
                                      int32_t index);