diff --git a/include/boost/regex/v4/basic_regex_parser.hpp b/include/boost/regex/v4/basic_regex_parser.hpp
index aae66aeb..ff0d4373 100644
--- a/include/boost/regex/v4/basic_regex_parser.hpp
+++ b/include/boost/regex/v4/basic_regex_parser.hpp
@@ -2596,7 +2596,7 @@ option_group_jump:
          re_alt* alt = static_cast<re_alt*>(this->insert_state(expected_alt_point, syntax_element_alt, sizeof(re_alt)));
          alt->alt.i = this->m_pdata->m_data.size() - this->getoffset(alt);
       }
-      else if(((std::ptrdiff_t)this->m_pdata->m_data.size() > static_cast<re_alt*>(b)->alt.i) && (static_cast<re_alt*>(b)->alt.i > 0) && this->getaddress(static_cast<re_alt*>(b)->alt.i, b)->type == syntax_element_alt)
+      else if(((std::ptrdiff_t)this->m_pdata->m_data.size() > (static_cast<re_alt*>(b)->alt.i + this->getoffset(b))) && (static_cast<re_alt*>(b)->alt.i > 0) && this->getaddress(static_cast<re_alt*>(b)->alt.i, b)->type == syntax_element_alt)
       {
          // Can't have seen more than one alternative:
          // Rewind to start of (? sequence: